Solid waste management in Freetown has been further complicated in the wake of rapid population growth and urbanization, resulting in considerable pressure to implement effective and sustainable solutions. This study ...Solid waste management in Freetown has been further complicated in the wake of rapid population growth and urbanization, resulting in considerable pressure to implement effective and sustainable solutions. This study fills the knowledge gap on the recycling infrastructure, solid waste collection processing, sorting and material recovery facilities specific to the Freetown waste management system. The aim of this study is to examine these components in terms of identifying inefficiencies and suggest sustainable practices to eliminate them. The study was guided by a mixed-method approach, which consisted of both quantitative and qualitative methods, and data collection was done through systematic random sampling. The sample of 384 respondents was collected, which includes stakeholders from a range of sectors. The outcome exhibited inefficient waste collection, a lack of formal recycling infrastructure, and suboptimal waste separation at house level, with 65.2% of respondents evidencing not separating their waste and 33% being without access to waste collection services that result in illegal dumping and environmental pollution. The analysis of the solid waste composition shows that a larger share of the waste generated in Freetown is composed of organic material (53% is being organic), which allows for composting programs to be initiated. This research establishes the inevitable requirement for infrastructure upgrading, mounting public awareness, and policy development. By taking into account these sectors, Freetown can become a more environment-friendly waste management system, which would mean a reduction in landfills and much-emphasized resource recovery.展开更多
Objective:Studies on the occupational health risks and experiences of healthcare waste handlers since the decline in coronavirus disease 2019(COVID-19)incidence are scarce in Nigeria.The current study aimed to examine...Objective:Studies on the occupational health risks and experiences of healthcare waste handlers since the decline in coronavirus disease 2019(COVID-19)incidence are scarce in Nigeria.The current study aimed to examine what seemed as the"hidden"and rarely researched area of practice from the standpoint of different stakeholders in a Nigerian Lassa fever treatment hospital.The primary objective was to understand the nature of waste handlers'practices and experiences and identify areas for improvement centred on supporting the development of best practices,in accordance with the World Health Organisation(WHO)guidelines.Methods:This study employed a qualitative case study design,gathering data from healthcare waste handlers(n=34)through four focus groups.Additionally,four in-depth interviews were conducted with ward managers and the infection control team to gain insight into the organisational framing of waste handling practice,the perceived challenges faced by waste handlers from their perspectives,and the provision of training and support.The qualitative data were audio-recorded and transcribed verbatim through manual processes and subjected to a reflexive thematic analysis conducted manually.Results:The findings revealed that waste handlers were subjected to various occupational health risks,including back pain,needlestick injuries,psychological distress,fatigue,anxiety,and prolonged exposure to sunlight.Concerns were raised regarding the inadequate supply of personal protective equipment and other essential tools,which suggests a need for organisational commitment to ensure the continual availability of these resources to protect the health and safety of these employees.A critical issue identified was the lack of comprehensive training for waste handlers,highlighting a form of organisational negligence.The consensual views expressed by the waste handlers indicated a sense of dissatisfaction with their working environment,largely attributable to organisational and societal stigmatisation.Furthermore,the study underscored that the hospital management faced significant financial constraints and advocated for increased funding to effectively implement best practice standards.Conclusion:To effectively manage healthcare waste and reduce hazards to waste handlers,the organisational leadership should prioritise training and support.This initiative will not only benefit the waste handlers but also the patients,other healthcare workers,and the general public.Although the findings focus on the case context of a Nigerian Lassa fever treatment hospital,the wider implications of this study are linked to the role of institutional support for waste handling practice.Moreover,it extends to the potential positions of institutions as displaying a form of"benign anomie"in not ensuring the wellbeing of waste handlers through sufficient regulation and governance focused on prioritisation,processes,and procedures.The study highlights the relevance of embedding WHO guidelines in other similar contexts as part of implementation across institutions involved with waste handling.展开更多
The dramatic rise in the number of people living in cities has made many environmental and social problems worse.The search for a productive method for disposing of solid waste is the most notable of these problems.Ma...The dramatic rise in the number of people living in cities has made many environmental and social problems worse.The search for a productive method for disposing of solid waste is the most notable of these problems.Many scholars have referred to it as a fuzzy multi-attribute or multi-criteria decision-making problem using various fuzzy set-like approaches because of the inclusion of criteria and anticipated ambiguity.The goal of the current study is to use an innovative methodology to address the expected uncertainties in the problem of solid waste site selection.The characteristics(or sub-attributes)that decision-makers select and the degree of approximation they accept for various options can both be indicators of these uncertainties.To tackle these problems,a novel mathematical structure known as the fuzzy parameterized possibility single valued neutrosophic hypersoft expert set(ρˆ-set),which is initially described,is integrated with a modified version of Sanchez’s method.Following this,an intelligent algorithm is suggested.The steps of the suggested algorithm are explained with an example that explains itself.The compatibility of solid waste management sites and systems is discussed,and rankings are established along with detailed justifications for their viability.This study’s strengths lie in its application of fuzzy parameterization and possibility grading to effectively handle the uncertainties embodied in the parameters’nature and alternative approximations,respectively.It uses specific mathematical formulations to compute the fuzzy parameterized degrees and possibility grades that are missing from the prior literature.It is simpler for the decisionmakers to look at each option separately because the decision is uncertain.Comparing the computed results,it is discovered that they are consistent and dependable because of their preferred properties.展开更多
The application of industrial solid wastes as environmentally functional materials for air pollutants control has gained much attention in recent years due to its potential to reduce air pollution in a cost-effective ...The application of industrial solid wastes as environmentally functional materials for air pollutants control has gained much attention in recent years due to its potential to reduce air pollution in a cost-effective manner.In this review,we investigate the development of industrialwaste-based functional materials for various gas pollutant removal and consider the relevant reaction mechanism according to different types of industrial solid waste.We see a recent effort towards achieving high-performance environmental functional materials via chemical or physical modification,in which the active components,pore size,and phase structure can be altered.The review will discuss the potential of using industrial solid wastes,these modified materials,or synthesized materials from raw waste precursors for the removal of air pollutants,including SO_(2),NO_(x),Hg^(0),H_(2)S,VOCs,and CO_(2).The challenges still need to be addressed to realize this potential and the prospects for future research fully.The suggestions for future directions include determining the optimal composition of these materials,calculating the real reaction rate and turnover frequency,developing effective treatment methods,and establishing chemical component databases of raw industrial solid waste for catalysts/adsorbent preparation.展开更多
The use of carbon from waste biomass has the potential to eliminate the drawbacks of Li-S batteries and improve their overall performance.Chrome-tanned-leather-shavings(CTLS)are a readily available waste product that ...The use of carbon from waste biomass has the potential to eliminate the drawbacks of Li-S batteries and improve their overall performance.Chrome-tanned-leather-shavings(CTLS)are a readily available waste product that can be transformed into porous carbon.We prepared an ac-tivated carbon by microwave pyrolysis combined with KOH activator using the CTLS as starting materials.The carbon had a specific surface area of 556 m^(2)g^(-1) and a honeycomb-like structure.Two kinds of N-doped activated carbons were then synthesized by thermal decomposition of the activated carbon,either combined with urea,or impregnated with eth-anolamine.Both N-doped activated carbons have an in-creased number of nitrogen and amine surface groups.However,only the urea treatment was effective in improv-ing the initial capacity of the cell(1363 mAh g^(-1)),which is probably linked to the sorption of long-chain polysulfides.This investigation confirms that it is possible to use the thermal de-composition of urea to obtain carbon materials from CTLS for use as the sulfur-host cathode in Li-S batteries and improve their performance.A radial basis function neural network was fitted to provide statistical support for the experimental results,which confirmed the importance of the nitrogen content of the carbons in determining the discharge capacity of the cells.展开更多
Industrial waste management constitutes a major challenge for sustainable development. This study aims to transform hardened cement waste stored in cement warehouses and in real estate construction sites into paving s...Industrial waste management constitutes a major challenge for sustainable development. This study aims to transform hardened cement waste stored in cement warehouses and in real estate construction sites into paving stones. This innovative solution will contribute to the protection of the environment and the reduction of inert industrial waste. To do this, paving stones based on hardened cement have been developed and characterized. The raw materials were subjected to physical and mechanical characterization tests. The hardened cement aggregates previously crushed with the 5/15 granular class were used as substitutes to replace the natural 5/15 aggregates in the hardened paving stones at contents ranging from 0 to 100%. The mechanical characterization results on the raw material showed that the hardened cement aggregate is made from lightweight aggregates. On the prepared mortar, in the fresh state, the Abrams cone slump test showed an increase in the quantity of waste water with the increase in the content of hardened cement aggregate. In the hardened state, physical (porosity, absorption and dry density) and mechanical (compression, splitting traction, 3-point bending traction and wear) characterization tests were carried out at periods of 7, 14 and 28 days of maturation in water on the cobblestones. These results show that the substitution of natural aggregates by hardened cement aggregates in increasingly large proportions leads to an improvement in compressive, flexural, splitting and wear resistance. In addition, the incorporation of hardened cement aggregate considerably slows down the mechanical degradation of the paving stones. They can, therefore, be used in road and interior or exterior floor coverings.展开更多
Waste heat generation,upgrading,and refrigeration are the fundamental ways to recover and utilize waste heat.Rationalizing the use of refrigerants also contributes to creating energy savings and minimizing carbon emis...Waste heat generation,upgrading,and refrigeration are the fundamental ways to recover and utilize waste heat.Rationalizing the use of refrigerants also contributes to creating energy savings and minimizing carbon emissions.This study evaluates the thermodynamics,economics,and environment of different refrigerants in three waste heat recovery schemes:generate electricity,heat pump,and refrigeration.Based on this,the entropy weight and technique for order preference by similarity to an ideal solution are combined to assess the overall performance of the refrigerants.A thorough analysis reveals that R1234ze(E)could replace R245fa and R123 in the organic Rankine cycle.The best refrigerant for vapor compression refrigeration and high-temperature heat pump systems is R1243zf.In addition,the multi-objective decision analysis shows that the performance difference among the nine selected refrigerants is the total cost,followed by the environmental impact.The approach successfully recognizes the variations between different refrigerants in the same waste heat recovery scheme and gives a thorough evaluation.It sets instructions for the future use of eco-friendly refrigerants and their application of waste heat recovery schemes.展开更多
The aim of this study was to describe waste management practices at Kisangani’s central market and the associated factors. A cross-sectional analytical study was carried out among 403 users of the Kisangani central m...The aim of this study was to describe waste management practices at Kisangani’s central market and the associated factors. A cross-sectional analytical study was carried out among 403 users of the Kisangani central market during the period from 01 July 2023 to 02 September 2023. It was found that 80.40% of respondents had poor waste management practices. There was an association between waste management practices and marital status, the category of respondent, the category of goods sold, knowledge of the definition of waste, the management mechanism in place and the availability of management materials and equipment. In conclusion, the proper management of waste from Kisangani’s central market by its users is proving to be a serious public health problem, and several factors are involved. Insufficient financial resources to make waste bins available at all vendors’ stalls, combined with the ineffectiveness of the hygiene committee, are undermining waste management at Kisangani’s central market, which calls for an effective management policy from the market’s managers and sufficient financial resources to alleviate the problem.展开更多
Electrocatalysis offers efficient and targeted conversion of monomers derived from waste polyester plastics to chemical products under ambient temperature and pressure conditions.This review provides analysis of resea...Electrocatalysis offers efficient and targeted conversion of monomers derived from waste polyester plastics to chemical products under ambient temperature and pressure conditions.This review provides analysis of research on electrochemical upgrading of monomers derived from waste polyester plastics published from2021 to present.Factors for assessing upgrading of waste polyester plastics include alkaline hydrolysis pretreatment,indices of electrochemical reaction process(activity,stability,and techno-economic a nalysis),separation,and product recovery.Types of depolymerization monomers and their value-added products are summarized along with electrocatalytic mechanisms and reaction pathways.Notably,cathode coupled reactions offer significant value for anodic waste plastic oxidation during electrolysis processes.Development of bifunctional electrocatalysts can reduce the cost of coupled systems and complexity of the electrolyzer.Upgrading and recycling of waste plastic monomers using electrocatalytic technology should undergo downstream processing to form high-value products containing C-N and C-S derived functional groups obtained from depolymerized monomers,Electrochemical conversion and upgrading of monomers derived from waste polyester plastics can contribute to industrialization and global economies and help to realize environmental sustainability.展开更多
Background: Waste management in Western Area Rural (WAR), Sierra Leone, is plagued by infrastructural and socioeconomic challenges, leading to environmental and health hazards such as flooding, air pollution, and vect...Background: Waste management in Western Area Rural (WAR), Sierra Leone, is plagued by infrastructural and socioeconomic challenges, leading to environmental and health hazards such as flooding, air pollution, and vector-borne diseases. Despite awareness campaigns, informal methods like open dumping and burning dominate. This study applies the Theory of Planned Behaviour (TPB) to analyse how attitudes, subjective norms, and perceived behavioural control influence waste management practices and barriers to proper disposal with potential solutions. Methods: A quantitative approach was employed, using stratified random sampling and structured questionnaires to collect data from 333 participants across ten communities in Western Area Rural (WAR). Data were analyzed using descriptive and inferential statistics to examine the relationship between socio-demographic variables and waste management practices. Results: While 98.2% of respondents acknowledged the importance of waste management, limited perceived behavioural control driven by financial constraints (83.8%), inadequate education (83.2%), and insufficient infrastructure (66.4%) hindered effective waste disposal ultimately linking health and environmental risks, such as flooding and marine pollution from plastic waste. Most respondents (68.8%) lacked access to formal waste services, with disposal occurring primarily via open dumping (62.9%) and burning (17.9%). Subjective norms reinforced informal disposal, as community waste-burning remained an accepted practice. Women were disproportionately affected due to economic constraints and larger household sizes. Despite these challenges, 93.1% were willing to engage in community clean-up efforts, indicating strong pro-environmental attitudes constrained by structural barriers. Conclusion: Findings underscore the need for integrated waste management strategies informed by TPB, targeting attitudes through education, reshaping social norms through community-driven initiatives, and enhancing perceived behavioural control by improving infrastructure and financial accessibility. Addressing gender disparities, strengthening public-private partnerships, and expanding recycling and composting programs can foster sustainable waste management in resource-constrained settings.展开更多
This article is descriptive research that takes into account the growing concerns of the authorities of the municipality of Coyah regarding waste management, as well as our desire to contribute to improving the living...This article is descriptive research that takes into account the growing concerns of the authorities of the municipality of Coyah regarding waste management, as well as our desire to contribute to improving the living conditions of the inhabitants of this region. The main objective is to assess the environmental impacts of uncontrolled waste collection points on the receiving environments, by characterizing and evaluating them. This will make it possible to propose appropriate measures for rational and sustainable management of the environment in Coyah. The study addresses the characterization and assessment of pollution of receiving environments, including water, soil and air. Environmental analyses were carried out according to standard methods of EPA (1997), adapted to the equipment of the companies Hach, Millipore and Verlan. During the environmental impact assessment, we identified the sources of pollution and assessed the potential impacts. This research highlighted the pollution of receiving environments by waste located in the vicinity of collection points, while considering solutions for efficient and sustainable waste management.展开更多
This work is devoted to numerical analysis of thermo-hydromechanical problem and cracking process in saturated porous media in the context of deep geological disposal of radioactive waste.The fundamental background of...This work is devoted to numerical analysis of thermo-hydromechanical problem and cracking process in saturated porous media in the context of deep geological disposal of radioactive waste.The fundamental background of thermo-poro-elastoplasticity theory is first summarized.The emphasis is put on the effect of pore fluid pressure on plastic deformation.A micromechanics-based elastoplastic model is then presented for a class of clayey rocks considered as host rock.Based on linear and nonlinear homogenization techniques,the proposed model is able to systematically account for the influences of porosity and mineral composition on macroscopic elastic properties and plastic yield strength.The initial anisotropy and time-dependent deformation are also taken into account.The induced cracking process is described by using a non-local damage model.A specific hybrid formulation is proposed,able to conveniently capture tensile,shear and mixed cracks.In particular,the influences of pore pressure and confining stress on the shear cracking mechanism are taken into account.The proposed model is applied to investigating thermo-hydromechanical responses and induced damage evolution in laboratory tests at the sample scale.In the last part,an in situ heating experiment is analyzed by using the proposed model.Numerical results are compared with experimental data and field measurements in terms of temperature variation,pore fluid pressure change and induced damaged zone.展开更多
This applied research seeks to explore feasible plant design for manufacturing insulation materials for construction projects using waste sheep fleece to address environmental issues related to wasted sheep wool and e...This applied research seeks to explore feasible plant design for manufacturing insulation materials for construction projects using waste sheep fleece to address environmental issues related to wasted sheep wool and enhance the gross national product. The process starts by collecting low-cost sheep fleece from farms and processed via a production line, including scouring, plucking, carding, thermal bonding, and packing. The design process involves determining an optimal location, infrastructure, staffing, machinery, environmental impact, and utilities. A final economic analysis is undertaken to estimate the product’s cost, selling price, and break-even point based on the anticipated capital and operational costs. The plant is intended to process 6778 tons of sheep wool annually. The study suggests that Mafraq Industrial City is a perfect location for the plant, and purchasing land and structures is the optimal option. The projected capital cost is 1,416,679 USD, while the anticipated operational costs amount to 3,206,275 USD. Insulation material production is estimated to be 114,756 m3 annually. The material may be manufactured into 1 m wide, 0.05 m thick sheets for 2.02 USD per square meter. Thus, for a 10-year plant, a 2.47 USD/m2 selling price breaks even in one year.展开更多
Bangladesh’s thriving okra cultivation sector annually yields substantial harvests, yet a significant portion of the plant remains underutilized after harvesting, posing as agricultural waste. This oversight neglects...Bangladesh’s thriving okra cultivation sector annually yields substantial harvests, yet a significant portion of the plant remains underutilized after harvesting, posing as agricultural waste. This oversight neglects the economic potential of okra fiber, which is versatile and valuable across various industries. This paper explores this untapped potential by investigating the physico-mechanical properties, chemical treatments, and fabrication techniques of okra fiber, drawing from a wealth of research. Comparative analyses with established natural fibers like jute and sisal shed light on okra fiber’s transformative role in Bangladesh’s economic landscape. Along with the applications in the fashion world, meticulous investigation into its mechanical, thermal, and morphological characteristics uncovers inherent strengths and integration pathways into industrial applications. Strategies for optimizing yield and quality, including novel approaches like photo-grafting and protein extraction, are explored. Considerations for cytotoxicity and environmental sustainability ensure its viability as a green resource. This research aims to unlock okra fiber’s full potential, positioning Bangladesh for sustainable economic development and innovation.展开更多
The utilization of seawater,a plentiful and cost-effective resource,instead of freshwater for H_(2)production through electrolysis has garnered significant attention.Herein,we present the synthesis of open-structured ...The utilization of seawater,a plentiful and cost-effective resource,instead of freshwater for H_(2)production through electrolysis has garnered significant attention.Herein,we present the synthesis of open-structured Fe-Co phosphide(FCP)nanocages for the overall seawater electrolysis,employing metallurgical solid waste(steel rolling sludge,SRS)as the precursor material.The FCP nanocages demonstrate exceptional catalytic activity for the hydrogen evolution reaction(HER)in all pH scales,achieving performance comparable to that of Pt/C catalysts at high current densities,The electrolyzer assembled with FCP‖FCP requires 1.57 and 1.68 V to achieve current densities of 10 and 100 mA cm^(-2),respectively.Furthermore,the assembled FCP electrolyzer showcases over 100 h of cycling stability and nearly 100%Faradaic efficiency.Crucially,it can be powered by commercially available silicon solar panels,operating under an intensity of 100 mW cm^(-2),and by wind-driven sources,rendering it highly promising for real-world applications,The seawater hydrogen evolution system coupled with levofloxacin(LEV)degradation was constructed for the first time.The oxidation potential of LEV oxidation reaction(LEVOR)was significantly lower than that of oxygen evolution reaction(OER),indicating that the LEV degradation reaction occurred preferentially and achieved a removal efficiency of 98.57%within 60 min.This study provides effective strategies for valorizing SRS and offers insights into the fabrication of highperformance catalysts.展开更多
Methane,the primary constituent of natural gas,shale gas,and flammable ice,serves as a crucial carbon-based energy source and chemical feedstock.Traditional gas reserves are universally acknowledged as limited and non...Methane,the primary constituent of natural gas,shale gas,and flammable ice,serves as a crucial carbon-based energy source and chemical feedstock.Traditional gas reserves are universally acknowledged as limited and non-renewable resources over an extended timespan stretching from decades to millennia.Biomethane,with its unique renewable properties,showcases remarkable development potential and presents a compelling supplement and even alternative for fossil fuel.Although catalytic hydrothermal processes appear as promising valorization routes to transfer biomass to sustainable methane,the safety and supply source of high-pressure hydrogen remain key factors restricting the widespread application.Herein,a catalytic approach without an external hydrogen source was developed to transform waste biomass resources into CH_(4)under the Ni-Mo catalyst.The total carbon yield of gas products reached up to 92.2%,of which the yield of methane and C2–C4 hydrocarbons were 44.9%and 3.0%,respectively.And it’s calculated that approximately 343.6 liters of CH_(4)could potentially be generated from 1 kilogram of raw biomass.Ni-based catalysts exhibited the robust activity in cleaving C–C and C–O bonds.And the introduction of an appropriate amount of molybdenum significantly enhanced catalytic performance of reforming and subsequent methanation reaction,likely due to the high adsorption capacity of highly dispersed Ni-Mo catalysts for carbon monoxide and hydrogen molecules,facilitating the methanation reaction.The pathway of catalytic methane production might be inferred that CO,H_(2)and a large number of oxygen-containing intermediates were formed via decarbonylation,dehydrogenation,and retro-aldol condensation reaction under hydrothermal condition.These intermediates then underwent the reforming reaction to generate H_(2)and CO_(2),ultimately forming CH_(4)through the methanation reaction.展开更多
For decades,lignin-the rigid polymer that gives plants their structure-has been the“problem child”of green chemistry.When processed,its molecules tangle like stubborn knots,forming useless clumps.Then came 2024’s t...For decades,lignin-the rigid polymer that gives plants their structure-has been the“problem child”of green chemistry.When processed,its molecules tangle like stubborn knots,forming useless clumps.Then came 2024’s transformative solution-breaking lignin’s tangles at the molecular level.In that May,a team led by scientists from the Chinese Academy of Sciences(CAS)came up with an approach to make this“knotty problem”profitable by hacking lignin’s chemistry to spin it into bio-bisphenols.展开更多
Due to the limited hydration capacity,solidification/stabilization(S/S)with waste concrete powder(WCP)has a low strength.Carbonation can reduce carbon dioxide(CO_(2))emissions and improve strength of lead-contaminated...Due to the limited hydration capacity,solidification/stabilization(S/S)with waste concrete powder(WCP)has a low strength.Carbonation can reduce carbon dioxide(CO_(2))emissions and improve strength of lead-contaminated soil,but its mechanism and environmental behaviors are unclear.In light of this,a comprehensive study was conducted on the compressive strength,lead immobilization,conductivity characteristics,and carbonation mechanism of carbonated Pb-contaminated soils stabilized with WCP compared to calcining 600℃WCP.Results indicated that with carbonation,the compressive strength of the samples was significantly improved at the early stage(1 d),resulting in increased unconfined compressive strength(UCS)by 2.5-5.2 times due to the filling of pores by calcite.It negatively affected the lead immobilization capacity of highly doped(30%)samples,while this effect reversed after 3 d of carbonating due to the reduced alkaline environment.The lead immobilization capacity decreased after 28 d of carbonating due to the cracking of samples and the influence of a lower pH on the solubility of lead-carbonated hydroxide((PbCO_(3))_(2)Pb(OH)_(2)).The water evaporation(saturation<16.8%)led to dry shrinkage cracking and decreased UCS of the samples.Based on this finding,a conductivity model was developed for carbonated and cured samples,accurately predicting changes in saturation levels(R^(2)=0.98).A relationship between conductivity and UCS or lead immobilization capacity was proposed.This research proposed an innovative method for the reduction of CO_(2)emission as well as laid down a theoretical basis for the recovery of WCP and lead-contaminated soils through carbonation.展开更多
Herein,cure characteristics,morphology,and mechanical properties of natural rubber filled with activated carbon-based materials were investigated.Carbon-based materials were prepared from bagasse,coffee grounds and pi...Herein,cure characteristics,morphology,and mechanical properties of natural rubber filled with activated carbon-based materials were investigated.Carbon-based materials were prepared from bagasse,coffee grounds and pineapple crowns by the pyrolysis method at temperatures in the range of 300℃.As-synthesized carbon materials were characterized by optical microscopy(OM),scanning electron microscopy(SEM),and Fourier-transform infrared spectroscopy(FTIR)to analyze size distribution,morphology,and functional groups,respectively.OM and SEM analysis revealed that particles,flakes,and a small quantity of fiber-like carbon were obtained using bagasse and pineapple crown as raw materials,while honeycomb-like carbon materials can be derived from coffee grounds.To investigate the mechanical properties,natural rubber was filled with carbon black and as-synthesized carbon materials by the internal mixing and compression molding process.Transmission electron microscopy(TEM)was utilized to characterize the dispersion of carbon materials in the rubber matrix.The results of tensile testing showed that the natural rubber mixed with as-synthesized carbon materials from pineapple crowns exhibited 54%and 74%improvement in the ultimate tensile strength and Young’s modulus,respectively,compared with natural rubber without filled carbon materials.The enhancement in mechanical properties by activated carbon materials derived from pineapple crowns can be attributed to the flake-and fiber-like structures and good dispersion of carbon materials in the rubber matrix.In addition,it is higher than that of rubber mixed with carbon black.The results demonstrated that as-synthesized carbon materials from pineapple crowns have the potential materials to substitute carbon black in the rubber compound industry.展开更多
Copper and cobalt were recovered from SICOMINES mining waste rock in the Democratic Republic of Congo.The process mineralogy of the samples was analyzed using scanning electron microscopy and energy dispersive spectro...Copper and cobalt were recovered from SICOMINES mining waste rock in the Democratic Republic of Congo.The process mineralogy of the samples was analyzed using scanning electron microscopy and energy dispersive spectroscopy.The results showed that copper minerals exhibited various forms and uneven particle sizes,while cobalt existed in the form of highly dispersed asbolane,and large amounts of easily slimed gangue minerals were filled in the samples,making it difficult to separate copper and cobalt minerals.The particle size range plays a decisive role in selecting the separation method for the copper−cobalt ore.Gravity separation was suitable for particles ranging from 43 to 246μm,while flotation was more effective for particles below 43μm.After ore grinding and particle size classification,applying a combined gravity separation(shaking table)−flotation method yielded concentrated minerals with a copper recovery of 72.83%and a cobalt recovery of 31.13%.展开更多
文摘Solid waste management in Freetown has been further complicated in the wake of rapid population growth and urbanization, resulting in considerable pressure to implement effective and sustainable solutions. This study fills the knowledge gap on the recycling infrastructure, solid waste collection processing, sorting and material recovery facilities specific to the Freetown waste management system. The aim of this study is to examine these components in terms of identifying inefficiencies and suggest sustainable practices to eliminate them. The study was guided by a mixed-method approach, which consisted of both quantitative and qualitative methods, and data collection was done through systematic random sampling. The sample of 384 respondents was collected, which includes stakeholders from a range of sectors. The outcome exhibited inefficient waste collection, a lack of formal recycling infrastructure, and suboptimal waste separation at house level, with 65.2% of respondents evidencing not separating their waste and 33% being without access to waste collection services that result in illegal dumping and environmental pollution. The analysis of the solid waste composition shows that a larger share of the waste generated in Freetown is composed of organic material (53% is being organic), which allows for composting programs to be initiated. This research establishes the inevitable requirement for infrastructure upgrading, mounting public awareness, and policy development. By taking into account these sectors, Freetown can become a more environment-friendly waste management system, which would mean a reduction in landfills and much-emphasized resource recovery.
基金Bangor University,UK supported this study through the International Science Partnerships Fund(ISPF)。
文摘Objective:Studies on the occupational health risks and experiences of healthcare waste handlers since the decline in coronavirus disease 2019(COVID-19)incidence are scarce in Nigeria.The current study aimed to examine what seemed as the"hidden"and rarely researched area of practice from the standpoint of different stakeholders in a Nigerian Lassa fever treatment hospital.The primary objective was to understand the nature of waste handlers'practices and experiences and identify areas for improvement centred on supporting the development of best practices,in accordance with the World Health Organisation(WHO)guidelines.Methods:This study employed a qualitative case study design,gathering data from healthcare waste handlers(n=34)through four focus groups.Additionally,four in-depth interviews were conducted with ward managers and the infection control team to gain insight into the organisational framing of waste handling practice,the perceived challenges faced by waste handlers from their perspectives,and the provision of training and support.The qualitative data were audio-recorded and transcribed verbatim through manual processes and subjected to a reflexive thematic analysis conducted manually.Results:The findings revealed that waste handlers were subjected to various occupational health risks,including back pain,needlestick injuries,psychological distress,fatigue,anxiety,and prolonged exposure to sunlight.Concerns were raised regarding the inadequate supply of personal protective equipment and other essential tools,which suggests a need for organisational commitment to ensure the continual availability of these resources to protect the health and safety of these employees.A critical issue identified was the lack of comprehensive training for waste handlers,highlighting a form of organisational negligence.The consensual views expressed by the waste handlers indicated a sense of dissatisfaction with their working environment,largely attributable to organisational and societal stigmatisation.Furthermore,the study underscored that the hospital management faced significant financial constraints and advocated for increased funding to effectively implement best practice standards.Conclusion:To effectively manage healthcare waste and reduce hazards to waste handlers,the organisational leadership should prioritise training and support.This initiative will not only benefit the waste handlers but also the patients,other healthcare workers,and the general public.Although the findings focus on the case context of a Nigerian Lassa fever treatment hospital,the wider implications of this study are linked to the role of institutional support for waste handling practice.Moreover,it extends to the potential positions of institutions as displaying a form of"benign anomie"in not ensuring the wellbeing of waste handlers through sufficient regulation and governance focused on prioritisation,processes,and procedures.The study highlights the relevance of embedding WHO guidelines in other similar contexts as part of implementation across institutions involved with waste handling.
文摘The dramatic rise in the number of people living in cities has made many environmental and social problems worse.The search for a productive method for disposing of solid waste is the most notable of these problems.Many scholars have referred to it as a fuzzy multi-attribute or multi-criteria decision-making problem using various fuzzy set-like approaches because of the inclusion of criteria and anticipated ambiguity.The goal of the current study is to use an innovative methodology to address the expected uncertainties in the problem of solid waste site selection.The characteristics(or sub-attributes)that decision-makers select and the degree of approximation they accept for various options can both be indicators of these uncertainties.To tackle these problems,a novel mathematical structure known as the fuzzy parameterized possibility single valued neutrosophic hypersoft expert set(ρˆ-set),which is initially described,is integrated with a modified version of Sanchez’s method.Following this,an intelligent algorithm is suggested.The steps of the suggested algorithm are explained with an example that explains itself.The compatibility of solid waste management sites and systems is discussed,and rankings are established along with detailed justifications for their viability.This study’s strengths lie in its application of fuzzy parameterization and possibility grading to effectively handle the uncertainties embodied in the parameters’nature and alternative approximations,respectively.It uses specific mathematical formulations to compute the fuzzy parameterized degrees and possibility grades that are missing from the prior literature.It is simpler for the decisionmakers to look at each option separately because the decision is uncertain.Comparing the computed results,it is discovered that they are consistent and dependable because of their preferred properties.
基金supported by National Natural Science Foundation of China(Grant No.52270106 and 22266021)Yunnan Major Scientific and Technological Projects(grant No.202202AG050005)Yunnan Fundamental Research Projects(grant No.202201AT070116).
文摘The application of industrial solid wastes as environmentally functional materials for air pollutants control has gained much attention in recent years due to its potential to reduce air pollution in a cost-effective manner.In this review,we investigate the development of industrialwaste-based functional materials for various gas pollutant removal and consider the relevant reaction mechanism according to different types of industrial solid waste.We see a recent effort towards achieving high-performance environmental functional materials via chemical or physical modification,in which the active components,pore size,and phase structure can be altered.The review will discuss the potential of using industrial solid wastes,these modified materials,or synthesized materials from raw waste precursors for the removal of air pollutants,including SO_(2),NO_(x),Hg^(0),H_(2)S,VOCs,and CO_(2).The challenges still need to be addressed to realize this potential and the prospects for future research fully.The suggestions for future directions include determining the optimal composition of these materials,calculating the real reaction rate and turnover frequency,developing effective treatment methods,and establishing chemical component databases of raw industrial solid waste for catalysts/adsorbent preparation.
文摘The use of carbon from waste biomass has the potential to eliminate the drawbacks of Li-S batteries and improve their overall performance.Chrome-tanned-leather-shavings(CTLS)are a readily available waste product that can be transformed into porous carbon.We prepared an ac-tivated carbon by microwave pyrolysis combined with KOH activator using the CTLS as starting materials.The carbon had a specific surface area of 556 m^(2)g^(-1) and a honeycomb-like structure.Two kinds of N-doped activated carbons were then synthesized by thermal decomposition of the activated carbon,either combined with urea,or impregnated with eth-anolamine.Both N-doped activated carbons have an in-creased number of nitrogen and amine surface groups.However,only the urea treatment was effective in improv-ing the initial capacity of the cell(1363 mAh g^(-1)),which is probably linked to the sorption of long-chain polysulfides.This investigation confirms that it is possible to use the thermal de-composition of urea to obtain carbon materials from CTLS for use as the sulfur-host cathode in Li-S batteries and improve their performance.A radial basis function neural network was fitted to provide statistical support for the experimental results,which confirmed the importance of the nitrogen content of the carbons in determining the discharge capacity of the cells.
文摘Industrial waste management constitutes a major challenge for sustainable development. This study aims to transform hardened cement waste stored in cement warehouses and in real estate construction sites into paving stones. This innovative solution will contribute to the protection of the environment and the reduction of inert industrial waste. To do this, paving stones based on hardened cement have been developed and characterized. The raw materials were subjected to physical and mechanical characterization tests. The hardened cement aggregates previously crushed with the 5/15 granular class were used as substitutes to replace the natural 5/15 aggregates in the hardened paving stones at contents ranging from 0 to 100%. The mechanical characterization results on the raw material showed that the hardened cement aggregate is made from lightweight aggregates. On the prepared mortar, in the fresh state, the Abrams cone slump test showed an increase in the quantity of waste water with the increase in the content of hardened cement aggregate. In the hardened state, physical (porosity, absorption and dry density) and mechanical (compression, splitting traction, 3-point bending traction and wear) characterization tests were carried out at periods of 7, 14 and 28 days of maturation in water on the cobblestones. These results show that the substitution of natural aggregates by hardened cement aggregates in increasingly large proportions leads to an improvement in compressive, flexural, splitting and wear resistance. In addition, the incorporation of hardened cement aggregate considerably slows down the mechanical degradation of the paving stones. They can, therefore, be used in road and interior or exterior floor coverings.
基金supported by the National Natural Science Foundation of China(22178190)the National Youth Natural Science Foundation of China(22408195).
文摘Waste heat generation,upgrading,and refrigeration are the fundamental ways to recover and utilize waste heat.Rationalizing the use of refrigerants also contributes to creating energy savings and minimizing carbon emissions.This study evaluates the thermodynamics,economics,and environment of different refrigerants in three waste heat recovery schemes:generate electricity,heat pump,and refrigeration.Based on this,the entropy weight and technique for order preference by similarity to an ideal solution are combined to assess the overall performance of the refrigerants.A thorough analysis reveals that R1234ze(E)could replace R245fa and R123 in the organic Rankine cycle.The best refrigerant for vapor compression refrigeration and high-temperature heat pump systems is R1243zf.In addition,the multi-objective decision analysis shows that the performance difference among the nine selected refrigerants is the total cost,followed by the environmental impact.The approach successfully recognizes the variations between different refrigerants in the same waste heat recovery scheme and gives a thorough evaluation.It sets instructions for the future use of eco-friendly refrigerants and their application of waste heat recovery schemes.
文摘The aim of this study was to describe waste management practices at Kisangani’s central market and the associated factors. A cross-sectional analytical study was carried out among 403 users of the Kisangani central market during the period from 01 July 2023 to 02 September 2023. It was found that 80.40% of respondents had poor waste management practices. There was an association between waste management practices and marital status, the category of respondent, the category of goods sold, knowledge of the definition of waste, the management mechanism in place and the availability of management materials and equipment. In conclusion, the proper management of waste from Kisangani’s central market by its users is proving to be a serious public health problem, and several factors are involved. Insufficient financial resources to make waste bins available at all vendors’ stalls, combined with the ineffectiveness of the hygiene committee, are undermining waste management at Kisangani’s central market, which calls for an effective management policy from the market’s managers and sufficient financial resources to alleviate the problem.
基金financially supported by the National Natural Science Foundation of China(Nos.22178181)the Natural Science Fund of Tianjin(No.21JCZDJC00180)the Fundamental Research Funds for the Central Universities(Nankai University(No.63243129)).
文摘Electrocatalysis offers efficient and targeted conversion of monomers derived from waste polyester plastics to chemical products under ambient temperature and pressure conditions.This review provides analysis of research on electrochemical upgrading of monomers derived from waste polyester plastics published from2021 to present.Factors for assessing upgrading of waste polyester plastics include alkaline hydrolysis pretreatment,indices of electrochemical reaction process(activity,stability,and techno-economic a nalysis),separation,and product recovery.Types of depolymerization monomers and their value-added products are summarized along with electrocatalytic mechanisms and reaction pathways.Notably,cathode coupled reactions offer significant value for anodic waste plastic oxidation during electrolysis processes.Development of bifunctional electrocatalysts can reduce the cost of coupled systems and complexity of the electrolyzer.Upgrading and recycling of waste plastic monomers using electrocatalytic technology should undergo downstream processing to form high-value products containing C-N and C-S derived functional groups obtained from depolymerized monomers,Electrochemical conversion and upgrading of monomers derived from waste polyester plastics can contribute to industrialization and global economies and help to realize environmental sustainability.
文摘Background: Waste management in Western Area Rural (WAR), Sierra Leone, is plagued by infrastructural and socioeconomic challenges, leading to environmental and health hazards such as flooding, air pollution, and vector-borne diseases. Despite awareness campaigns, informal methods like open dumping and burning dominate. This study applies the Theory of Planned Behaviour (TPB) to analyse how attitudes, subjective norms, and perceived behavioural control influence waste management practices and barriers to proper disposal with potential solutions. Methods: A quantitative approach was employed, using stratified random sampling and structured questionnaires to collect data from 333 participants across ten communities in Western Area Rural (WAR). Data were analyzed using descriptive and inferential statistics to examine the relationship between socio-demographic variables and waste management practices. Results: While 98.2% of respondents acknowledged the importance of waste management, limited perceived behavioural control driven by financial constraints (83.8%), inadequate education (83.2%), and insufficient infrastructure (66.4%) hindered effective waste disposal ultimately linking health and environmental risks, such as flooding and marine pollution from plastic waste. Most respondents (68.8%) lacked access to formal waste services, with disposal occurring primarily via open dumping (62.9%) and burning (17.9%). Subjective norms reinforced informal disposal, as community waste-burning remained an accepted practice. Women were disproportionately affected due to economic constraints and larger household sizes. Despite these challenges, 93.1% were willing to engage in community clean-up efforts, indicating strong pro-environmental attitudes constrained by structural barriers. Conclusion: Findings underscore the need for integrated waste management strategies informed by TPB, targeting attitudes through education, reshaping social norms through community-driven initiatives, and enhancing perceived behavioural control by improving infrastructure and financial accessibility. Addressing gender disparities, strengthening public-private partnerships, and expanding recycling and composting programs can foster sustainable waste management in resource-constrained settings.
文摘This article is descriptive research that takes into account the growing concerns of the authorities of the municipality of Coyah regarding waste management, as well as our desire to contribute to improving the living conditions of the inhabitants of this region. The main objective is to assess the environmental impacts of uncontrolled waste collection points on the receiving environments, by characterizing and evaluating them. This will make it possible to propose appropriate measures for rational and sustainable management of the environment in Coyah. The study addresses the characterization and assessment of pollution of receiving environments, including water, soil and air. Environmental analyses were carried out according to standard methods of EPA (1997), adapted to the equipment of the companies Hach, Millipore and Verlan. During the environmental impact assessment, we identified the sources of pollution and assessed the potential impacts. This research highlighted the pollution of receiving environments by waste located in the vicinity of collection points, while considering solutions for efficient and sustainable waste management.
基金supported by the French National Agency for radioactive waste management(ANDRA).
文摘This work is devoted to numerical analysis of thermo-hydromechanical problem and cracking process in saturated porous media in the context of deep geological disposal of radioactive waste.The fundamental background of thermo-poro-elastoplasticity theory is first summarized.The emphasis is put on the effect of pore fluid pressure on plastic deformation.A micromechanics-based elastoplastic model is then presented for a class of clayey rocks considered as host rock.Based on linear and nonlinear homogenization techniques,the proposed model is able to systematically account for the influences of porosity and mineral composition on macroscopic elastic properties and plastic yield strength.The initial anisotropy and time-dependent deformation are also taken into account.The induced cracking process is described by using a non-local damage model.A specific hybrid formulation is proposed,able to conveniently capture tensile,shear and mixed cracks.In particular,the influences of pore pressure and confining stress on the shear cracking mechanism are taken into account.The proposed model is applied to investigating thermo-hydromechanical responses and induced damage evolution in laboratory tests at the sample scale.In the last part,an in situ heating experiment is analyzed by using the proposed model.Numerical results are compared with experimental data and field measurements in terms of temperature variation,pore fluid pressure change and induced damaged zone.
文摘This applied research seeks to explore feasible plant design for manufacturing insulation materials for construction projects using waste sheep fleece to address environmental issues related to wasted sheep wool and enhance the gross national product. The process starts by collecting low-cost sheep fleece from farms and processed via a production line, including scouring, plucking, carding, thermal bonding, and packing. The design process involves determining an optimal location, infrastructure, staffing, machinery, environmental impact, and utilities. A final economic analysis is undertaken to estimate the product’s cost, selling price, and break-even point based on the anticipated capital and operational costs. The plant is intended to process 6778 tons of sheep wool annually. The study suggests that Mafraq Industrial City is a perfect location for the plant, and purchasing land and structures is the optimal option. The projected capital cost is 1,416,679 USD, while the anticipated operational costs amount to 3,206,275 USD. Insulation material production is estimated to be 114,756 m3 annually. The material may be manufactured into 1 m wide, 0.05 m thick sheets for 2.02 USD per square meter. Thus, for a 10-year plant, a 2.47 USD/m2 selling price breaks even in one year.
文摘Bangladesh’s thriving okra cultivation sector annually yields substantial harvests, yet a significant portion of the plant remains underutilized after harvesting, posing as agricultural waste. This oversight neglects the economic potential of okra fiber, which is versatile and valuable across various industries. This paper explores this untapped potential by investigating the physico-mechanical properties, chemical treatments, and fabrication techniques of okra fiber, drawing from a wealth of research. Comparative analyses with established natural fibers like jute and sisal shed light on okra fiber’s transformative role in Bangladesh’s economic landscape. Along with the applications in the fashion world, meticulous investigation into its mechanical, thermal, and morphological characteristics uncovers inherent strengths and integration pathways into industrial applications. Strategies for optimizing yield and quality, including novel approaches like photo-grafting and protein extraction, are explored. Considerations for cytotoxicity and environmental sustainability ensure its viability as a green resource. This research aims to unlock okra fiber’s full potential, positioning Bangladesh for sustainable economic development and innovation.
基金supported by the National Natural Science Foundation of China(51874039).
文摘The utilization of seawater,a plentiful and cost-effective resource,instead of freshwater for H_(2)production through electrolysis has garnered significant attention.Herein,we present the synthesis of open-structured Fe-Co phosphide(FCP)nanocages for the overall seawater electrolysis,employing metallurgical solid waste(steel rolling sludge,SRS)as the precursor material.The FCP nanocages demonstrate exceptional catalytic activity for the hydrogen evolution reaction(HER)in all pH scales,achieving performance comparable to that of Pt/C catalysts at high current densities,The electrolyzer assembled with FCP‖FCP requires 1.57 and 1.68 V to achieve current densities of 10 and 100 mA cm^(-2),respectively.Furthermore,the assembled FCP electrolyzer showcases over 100 h of cycling stability and nearly 100%Faradaic efficiency.Crucially,it can be powered by commercially available silicon solar panels,operating under an intensity of 100 mW cm^(-2),and by wind-driven sources,rendering it highly promising for real-world applications,The seawater hydrogen evolution system coupled with levofloxacin(LEV)degradation was constructed for the first time.The oxidation potential of LEV oxidation reaction(LEVOR)was significantly lower than that of oxygen evolution reaction(OER),indicating that the LEV degradation reaction occurred preferentially and achieved a removal efficiency of 98.57%within 60 min.This study provides effective strategies for valorizing SRS and offers insights into the fabrication of highperformance catalysts.
文摘Methane,the primary constituent of natural gas,shale gas,and flammable ice,serves as a crucial carbon-based energy source and chemical feedstock.Traditional gas reserves are universally acknowledged as limited and non-renewable resources over an extended timespan stretching from decades to millennia.Biomethane,with its unique renewable properties,showcases remarkable development potential and presents a compelling supplement and even alternative for fossil fuel.Although catalytic hydrothermal processes appear as promising valorization routes to transfer biomass to sustainable methane,the safety and supply source of high-pressure hydrogen remain key factors restricting the widespread application.Herein,a catalytic approach without an external hydrogen source was developed to transform waste biomass resources into CH_(4)under the Ni-Mo catalyst.The total carbon yield of gas products reached up to 92.2%,of which the yield of methane and C2–C4 hydrocarbons were 44.9%and 3.0%,respectively.And it’s calculated that approximately 343.6 liters of CH_(4)could potentially be generated from 1 kilogram of raw biomass.Ni-based catalysts exhibited the robust activity in cleaving C–C and C–O bonds.And the introduction of an appropriate amount of molybdenum significantly enhanced catalytic performance of reforming and subsequent methanation reaction,likely due to the high adsorption capacity of highly dispersed Ni-Mo catalysts for carbon monoxide and hydrogen molecules,facilitating the methanation reaction.The pathway of catalytic methane production might be inferred that CO,H_(2)and a large number of oxygen-containing intermediates were formed via decarbonylation,dehydrogenation,and retro-aldol condensation reaction under hydrothermal condition.These intermediates then underwent the reforming reaction to generate H_(2)and CO_(2),ultimately forming CH_(4)through the methanation reaction.
文摘For decades,lignin-the rigid polymer that gives plants their structure-has been the“problem child”of green chemistry.When processed,its molecules tangle like stubborn knots,forming useless clumps.Then came 2024’s transformative solution-breaking lignin’s tangles at the molecular level.In that May,a team led by scientists from the Chinese Academy of Sciences(CAS)came up with an approach to make this“knotty problem”profitable by hacking lignin’s chemistry to spin it into bio-bisphenols.
基金the National Natural Science Foundation of China(Grant Nos.42177163 and 42071080)the China Postdoctoral Science Foundation(Grant No.2022M723347).
文摘Due to the limited hydration capacity,solidification/stabilization(S/S)with waste concrete powder(WCP)has a low strength.Carbonation can reduce carbon dioxide(CO_(2))emissions and improve strength of lead-contaminated soil,but its mechanism and environmental behaviors are unclear.In light of this,a comprehensive study was conducted on the compressive strength,lead immobilization,conductivity characteristics,and carbonation mechanism of carbonated Pb-contaminated soils stabilized with WCP compared to calcining 600℃WCP.Results indicated that with carbonation,the compressive strength of the samples was significantly improved at the early stage(1 d),resulting in increased unconfined compressive strength(UCS)by 2.5-5.2 times due to the filling of pores by calcite.It negatively affected the lead immobilization capacity of highly doped(30%)samples,while this effect reversed after 3 d of carbonating due to the reduced alkaline environment.The lead immobilization capacity decreased after 28 d of carbonating due to the cracking of samples and the influence of a lower pH on the solubility of lead-carbonated hydroxide((PbCO_(3))_(2)Pb(OH)_(2)).The water evaporation(saturation<16.8%)led to dry shrinkage cracking and decreased UCS of the samples.Based on this finding,a conductivity model was developed for carbonated and cured samples,accurately predicting changes in saturation levels(R^(2)=0.98).A relationship between conductivity and UCS or lead immobilization capacity was proposed.This research proposed an innovative method for the reduction of CO_(2)emission as well as laid down a theoretical basis for the recovery of WCP and lead-contaminated soils through carbonation.
基金funded by Faculty of Engineering,Burapha University,grant number 003/2567.
文摘Herein,cure characteristics,morphology,and mechanical properties of natural rubber filled with activated carbon-based materials were investigated.Carbon-based materials were prepared from bagasse,coffee grounds and pineapple crowns by the pyrolysis method at temperatures in the range of 300℃.As-synthesized carbon materials were characterized by optical microscopy(OM),scanning electron microscopy(SEM),and Fourier-transform infrared spectroscopy(FTIR)to analyze size distribution,morphology,and functional groups,respectively.OM and SEM analysis revealed that particles,flakes,and a small quantity of fiber-like carbon were obtained using bagasse and pineapple crown as raw materials,while honeycomb-like carbon materials can be derived from coffee grounds.To investigate the mechanical properties,natural rubber was filled with carbon black and as-synthesized carbon materials by the internal mixing and compression molding process.Transmission electron microscopy(TEM)was utilized to characterize the dispersion of carbon materials in the rubber matrix.The results of tensile testing showed that the natural rubber mixed with as-synthesized carbon materials from pineapple crowns exhibited 54%and 74%improvement in the ultimate tensile strength and Young’s modulus,respectively,compared with natural rubber without filled carbon materials.The enhancement in mechanical properties by activated carbon materials derived from pineapple crowns can be attributed to the flake-and fiber-like structures and good dispersion of carbon materials in the rubber matrix.In addition,it is higher than that of rubber mixed with carbon black.The results demonstrated that as-synthesized carbon materials from pineapple crowns have the potential materials to substitute carbon black in the rubber compound industry.
基金National Key Research and Development Program of China (No. 2020YFC1909202)Major Science and Technology Program of Yunnan Province,China (No. 202202AB080012) for financial support。
文摘Copper and cobalt were recovered from SICOMINES mining waste rock in the Democratic Republic of Congo.The process mineralogy of the samples was analyzed using scanning electron microscopy and energy dispersive spectroscopy.The results showed that copper minerals exhibited various forms and uneven particle sizes,while cobalt existed in the form of highly dispersed asbolane,and large amounts of easily slimed gangue minerals were filled in the samples,making it difficult to separate copper and cobalt minerals.The particle size range plays a decisive role in selecting the separation method for the copper−cobalt ore.Gravity separation was suitable for particles ranging from 43 to 246μm,while flotation was more effective for particles below 43μm.After ore grinding and particle size classification,applying a combined gravity separation(shaking table)−flotation method yielded concentrated minerals with a copper recovery of 72.83%and a cobalt recovery of 31.13%.
