Herein,we present a simple strategy for preparing monolithic sodalite adsorbents via sequential additive manufacturing and post-treatments.In detail,the method includes(i)3D printing of cylindrical monoliths using cla...Herein,we present a simple strategy for preparing monolithic sodalite adsorbents via sequential additive manufacturing and post-treatments.In detail,the method includes(i)3D printing of cylindrical monoliths using clay as the base material;(ii)thermal activation of the 3D-printed clay monoliths by calcination(to produce reactive alumina and silica species and enable mechanical stabilization);(iii)conversion of the activated clay monoliths to hierarchical porous sodalite monoliths via hydrothermal alkaline treatment.Parametric studies on the effect of calcination temperature,alkaline concentration and hydrothermal treatment time on the property of the resulting materials(such as phase composition and morphology)at different stages of preparation was conducted.Under the optimal conditions(i.e.,calcination temperature of 850℃,NaOH concentration of 3.3 mol·L^(-1),reaction temperature of 150℃,and reaction time of 6 h),a high-quality pure sodalite monolith was obtained,which possesses a relatively high BET surface area(58 m^(2)·g^(-1))and hierarchically micro-meso-macroporous structure.In the proposed application of continuous removal of heavy metals(chromium ion as the model)from wastewater,the developed 3D-printed sodalite monolith showed excellent Cr^(3+)removal performance and fast kinetics(~98%removal efficiency within 25 cycles),which outperformed the packed bed using sodalite pellets(made by extrusion).展开更多
This paper describes the preparation of a membrane of polyacrylonitrile(PAN)and its corresponding membrane coated with polyaniline(PANI)for the adsorption of heavy metal ions.Scanning electron microscopy micrographs r...This paper describes the preparation of a membrane of polyacrylonitrile(PAN)and its corresponding membrane coated with polyaniline(PANI)for the adsorption of heavy metal ions.Scanning electron microscopy micrographs revealed that all the membranes exhibited nanofibrous morphology.The prepared membranes were characterized by Fourier transform infrared spectroscopy(FTIR).The prepared membranes were used as an adsorbent for hazardous heavy metal ions Pb^(2+) and Cr_(2)O^(2-)_(7).The adsorption capacity and the removal efficiency of the membranes were examined as function of the initial adsorbate concentration and pH of the medium.Coated membranes with PANI showed better adsorption performance and their direct current(DC)conductivities were correlated to heavy metal ion concentrations.Adsorption isotherms were also performed,and the adsorption process was tested according to the Langmuir and Freundlich models.The regeneration and reuse of the prepared membranes to re-adsorb heavy metal ions were also investigated.The enhancement in adsorption performance and reusability of PANI-coated membranes in comparison with non-coated ones is fully discussed.The results show that the maximum adsorption capacities of lead and chromate ions on the PANI-coated membranes are 290.12 and 1202.53 mg/g,respectively.展开更多
Converting peanut shells into biochar by pyrolysis was considered an environmentally friendly and efficient method for agricultural solid waste disposal.The properties of peanut shell-derived biochar(PBC)under differe...Converting peanut shells into biochar by pyrolysis was considered an environmentally friendly and efficient method for agricultural solid waste disposal.The properties of peanut shell-derived biochar(PBC)under different temperature and its adsorption capacity of heavy metals were investigated.It was found that PBC400 exhibited the highest cumulative capability for heavy metals elimination in single solute because of its high specific surface area and rich functional groups.Furthermore,the competitive adsorption revealed that PBC had a substantial difference in adsorption affinity from diverse heavy metal ions,sorption capacity decreased as Pb2+>Cu2+>Cd2+>Ni2+>Zn2+,which was lower than in a single solute.The adsorption process using selected biochar was optimized with respect to p H,reaction time,adsorbent dose,and initial concentration of heavy metals.The kinetic data was well fitted with PSO model,and the Langmuir model was adopted for adsorption equilibrium data in both cases of single solutes and mixed solutes for all heavy metals,which indicated that the removal course was primarily explained by monolayer adsorption,and chemical adsorption occupied an important role.Therefore,peanut shells derived biochar could be a potential and green adsorbent for wastewater treatment.展开更多
Heavy metals⁃polluted water has negative impact on the ecosystem.In Malaysia,minimum discharge limit for Cu^(2+)and Zn^(2+)are 1 mg/L and 2 mg/L,respectively.Zeolite is a highly porous adsorbent and its performance is...Heavy metals⁃polluted water has negative impact on the ecosystem.In Malaysia,minimum discharge limit for Cu^(2+)and Zn^(2+)are 1 mg/L and 2 mg/L,respectively.Zeolite is a highly porous adsorbent and its performance is affected by various factors,including contact time and pH.Thus,the objective of this study is to identify an ideal operating condition to treat Cu^(2+)and Zn^(2+)solutions up to the allowable discharge limit,by considering the pH and contact time factors.Six kinetic models were studied to identify the adsorption mechanism of the heavy metal removal process.Single solute batch adsorption experiment was conducted within pH 3-11 from 30 to 150 min.Results showed that hydration enthalpy(ΔHhyd)governed the selectivity of heavy metals,where a maximum of 90.87%Zn^(2+)(ΔH_(hyd)=-1955 kJ/mol)and 82.15%Cu^(2+)(ΔH_(hyd)=-2010 kJ/mol)removals were found at pH≥7.Without pH adjustment,selectivity towards Cu^(2+)was higher compared with Zn^(2+)due to the size of hydration radii,where Cu^(2+)is 0.11Åsmaller than Zn^(2+).By considering both pH and contact time factors,this study shows that by adjusting the pH of Zn^(2+)solutions to a minimum pH value of 7,the contact time required to achieve maximum Zn^(2+)removal rate was 90%,which can be achieved within 60 min.Meanwhile,zeolite performed better in Cu^(2+)removal without any pH adjustment where a maximum of 94%was achieved at 120 min.Final concentration of 0.523 mg/L Cu^(2+)and 0.981 mg/L Zn^(2+)were obtained in this study.Kinetic study showed that Ritchie’s equation predicted Cu^(2+)adsorption the best,while Zn^(2+)adsorption could be represented by Elovich model.This suggested that the adsorption on the activate site governed Cu^(2+)and Zn^(2+)removal process.Hence,future work should focus on modifying zeolite surface to improve the adsorptive performance.展开更多
Alginate blended with cellulose nanocrystals(CNC),cellulose nanofibers(CNF),and tri-carboxylate cellulose nanofibers(TPC-CNF)prepared and encapsulated in the form of microcapsules(bio-polymeric beads).The cellulosic n...Alginate blended with cellulose nanocrystals(CNC),cellulose nanofibers(CNF),and tri-carboxylate cellulose nanofibers(TPC-CNF)prepared and encapsulated in the form of microcapsules(bio-polymeric beads).The cellulosic nanomaterials that used in this study were investigated as nanomaterials for wastewater treatment applications.Batch experiments were performed to study the removal of copper,lead,magnesium,and iron from aqueous solutions by the prepared beads.The effects of the sorbent dosage and the modified polymers on the removing efficiency of the metal cations were examined.Atomic absorption was used to measure the metal ions concentrations.The modified bio-polymeric beads(Alg-CNF,Alg-CNC,and Alg-TPC-CNF)exhibited high-efficiency towards removing of the metal cations;Cu^(2+),Pb^(2+),Mg^(2+),and Fe^(2+).The Alg-TPC-CNF composite was exhibited excellent removing efficiency which around 95%for Pb,92%for Cu,43%for Fe and 54%for Mg.These outcomes affirm that the utilization of nanomaterials giving higher adsorption capacities contrasted with similar material in its micro or macrostructure form.展开更多
The fabrication of a fully bio-sourced adsorbent of Cd(Ⅱ)by covalent immobilization of quinine on cellulose paper is described.The double bond of commercially available quinine was converted to a terminal alkyne func...The fabrication of a fully bio-sourced adsorbent of Cd(Ⅱ)by covalent immobilization of quinine on cellulose paper is described.The double bond of commercially available quinine was converted to a terminal alkyne function which was reacted with cellulose paper,chemically modified with azide functions,through a 1,3-dipolar cycloaddition,leading to Cell-Quin.The adsorption efficiency of Cell-Quin was investigated to determine the optimal pH,contact time and dose of adsorbent,ultimately leading to high levels of removal.The mechanism of adsorption of Cell-Quin was deeply rationalized through kinetic experiments and isotherm modeling.We also showed that Cell-Quin could adsorb other heavy metals such as Cu(Ⅱ),Pb(Ⅱ),Ni(Ⅱ)and Zn(Ⅱ).展开更多
A new route to prepare zeolitic material was introduced in this work. Compared with traditional methods, the new route showed lower energy consume. The effect of pre-treatment conditions on structure and crystalline p...A new route to prepare zeolitic material was introduced in this work. Compared with traditional methods, the new route showed lower energy consume. The effect of pre-treatment conditions on structure and crystalline phase was investigated, revealing that the mullite crystalline phase in fly ash could be converted to amorphous phase by alkali at low temperature. The removal performance of heavy metal ions on designed material was also investigated, and we found that the intermediate product showed higher adsorption capacity on Ni^(2+) than zeolite A.展开更多
Physical separation apparatuses;a vibrating screen, a 4-inch hydrocyclone and a Multi-Gravity Separator (MGS) were used to recover phosphorus as MAP (magnesium ammonium phosphate, MgNH<sub>4</sub>PO<sub...Physical separation apparatuses;a vibrating screen, a 4-inch hydrocyclone and a Multi-Gravity Separator (MGS) were used to recover phosphorus as MAP (magnesium ammonium phosphate, MgNH<sub>4</sub>PO<sub>4.</sub>6H<sub>2</sub>O) from anaerobic digested sludge of two sewage-treatment plants A and B. For plant A, the MAP grade increased from 0.08% to 88.9% with 90.4% recovery and for plant B, the grade increased from 0.11% to 73.8 with 93.2% recovery. The collected MAP products containing impurities such as organic materials and heavy metals were further upgraded through dry and wet magnetic separation tests at different magnetic flux densities. A dry magnetic separator was tested on both MAP products (MAP-A and MAP-B), while the wet magnetic separation process was exclusively experimented for the removal of impurities from MAP-B. Feed samples, as well as magnetic and nonmagnetic products were analyzed by absorption spectroscopy, XRD, ICP-AES, polarizing microscope observation, and SEM-EDX. The grade of MAP products could be improved by about 4% - 9% after magnetic separation (the most appropriate magnetic force being 15,000 Gauss). During both dry and wet magnetic separation processes, not only heavy metals have been removed, but also nonmagnetic constituents like Al, Ba, and Ca. This may be attributed to the attachment of fine magnetic particles on the nonmagnetic surfaces, rendering them magnetic properties.展开更多
基金the Key Project on Intergovernmental International Science, Technology and Innovation (STI) Cooperation/STI Cooperation with Hong Kong, MacaoTaiwan of China’s National Key Research & Development Programme (2019YFE0123200)+1 种基金the National Natural Science Foundation of China (22078348)funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement (No. 872102)
文摘Herein,we present a simple strategy for preparing monolithic sodalite adsorbents via sequential additive manufacturing and post-treatments.In detail,the method includes(i)3D printing of cylindrical monoliths using clay as the base material;(ii)thermal activation of the 3D-printed clay monoliths by calcination(to produce reactive alumina and silica species and enable mechanical stabilization);(iii)conversion of the activated clay monoliths to hierarchical porous sodalite monoliths via hydrothermal alkaline treatment.Parametric studies on the effect of calcination temperature,alkaline concentration and hydrothermal treatment time on the property of the resulting materials(such as phase composition and morphology)at different stages of preparation was conducted.Under the optimal conditions(i.e.,calcination temperature of 850℃,NaOH concentration of 3.3 mol·L^(-1),reaction temperature of 150℃,and reaction time of 6 h),a high-quality pure sodalite monolith was obtained,which possesses a relatively high BET surface area(58 m^(2)·g^(-1))and hierarchically micro-meso-macroporous structure.In the proposed application of continuous removal of heavy metals(chromium ion as the model)from wastewater,the developed 3D-printed sodalite monolith showed excellent Cr^(3+)removal performance and fast kinetics(~98%removal efficiency within 25 cycles),which outperformed the packed bed using sodalite pellets(made by extrusion).
文摘This paper describes the preparation of a membrane of polyacrylonitrile(PAN)and its corresponding membrane coated with polyaniline(PANI)for the adsorption of heavy metal ions.Scanning electron microscopy micrographs revealed that all the membranes exhibited nanofibrous morphology.The prepared membranes were characterized by Fourier transform infrared spectroscopy(FTIR).The prepared membranes were used as an adsorbent for hazardous heavy metal ions Pb^(2+) and Cr_(2)O^(2-)_(7).The adsorption capacity and the removal efficiency of the membranes were examined as function of the initial adsorbate concentration and pH of the medium.Coated membranes with PANI showed better adsorption performance and their direct current(DC)conductivities were correlated to heavy metal ion concentrations.Adsorption isotherms were also performed,and the adsorption process was tested according to the Langmuir and Freundlich models.The regeneration and reuse of the prepared membranes to re-adsorb heavy metal ions were also investigated.The enhancement in adsorption performance and reusability of PANI-coated membranes in comparison with non-coated ones is fully discussed.The results show that the maximum adsorption capacities of lead and chromate ions on the PANI-coated membranes are 290.12 and 1202.53 mg/g,respectively.
基金financially supported by State’s Key Project of Research and Development Plan,China(y804091001)National Natural Science Foundation of China(51776211)Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(GML2019ZD0101)。
文摘Converting peanut shells into biochar by pyrolysis was considered an environmentally friendly and efficient method for agricultural solid waste disposal.The properties of peanut shell-derived biochar(PBC)under different temperature and its adsorption capacity of heavy metals were investigated.It was found that PBC400 exhibited the highest cumulative capability for heavy metals elimination in single solute because of its high specific surface area and rich functional groups.Furthermore,the competitive adsorption revealed that PBC had a substantial difference in adsorption affinity from diverse heavy metal ions,sorption capacity decreased as Pb2+>Cu2+>Cd2+>Ni2+>Zn2+,which was lower than in a single solute.The adsorption process using selected biochar was optimized with respect to p H,reaction time,adsorbent dose,and initial concentration of heavy metals.The kinetic data was well fitted with PSO model,and the Langmuir model was adopted for adsorption equilibrium data in both cases of single solutes and mixed solutes for all heavy metals,which indicated that the removal course was primarily explained by monolayer adsorption,and chemical adsorption occupied an important role.Therefore,peanut shells derived biochar could be a potential and green adsorbent for wastewater treatment.
文摘Heavy metals⁃polluted water has negative impact on the ecosystem.In Malaysia,minimum discharge limit for Cu^(2+)and Zn^(2+)are 1 mg/L and 2 mg/L,respectively.Zeolite is a highly porous adsorbent and its performance is affected by various factors,including contact time and pH.Thus,the objective of this study is to identify an ideal operating condition to treat Cu^(2+)and Zn^(2+)solutions up to the allowable discharge limit,by considering the pH and contact time factors.Six kinetic models were studied to identify the adsorption mechanism of the heavy metal removal process.Single solute batch adsorption experiment was conducted within pH 3-11 from 30 to 150 min.Results showed that hydration enthalpy(ΔHhyd)governed the selectivity of heavy metals,where a maximum of 90.87%Zn^(2+)(ΔH_(hyd)=-1955 kJ/mol)and 82.15%Cu^(2+)(ΔH_(hyd)=-2010 kJ/mol)removals were found at pH≥7.Without pH adjustment,selectivity towards Cu^(2+)was higher compared with Zn^(2+)due to the size of hydration radii,where Cu^(2+)is 0.11Åsmaller than Zn^(2+).By considering both pH and contact time factors,this study shows that by adjusting the pH of Zn^(2+)solutions to a minimum pH value of 7,the contact time required to achieve maximum Zn^(2+)removal rate was 90%,which can be achieved within 60 min.Meanwhile,zeolite performed better in Cu^(2+)removal without any pH adjustment where a maximum of 94%was achieved at 120 min.Final concentration of 0.523 mg/L Cu^(2+)and 0.981 mg/L Zn^(2+)were obtained in this study.Kinetic study showed that Ritchie’s equation predicted Cu^(2+)adsorption the best,while Zn^(2+)adsorption could be represented by Elovich model.This suggested that the adsorption on the activate site governed Cu^(2+)and Zn^(2+)removal process.Hence,future work should focus on modifying zeolite surface to improve the adsorptive performance.
基金The authors acknowledge the Science and Technology Development Fund(STDF),Egypt for financial support of the research activities related to the projectProject ID 15203+1 种基金The authors also gratefully express their sincere gratitude to the“PHC-UTIQUE CMCU”(18G1132)the CMPTM(17TM22),as well as to the Tunisian Ministry of Higher Education for the financial support.
文摘Alginate blended with cellulose nanocrystals(CNC),cellulose nanofibers(CNF),and tri-carboxylate cellulose nanofibers(TPC-CNF)prepared and encapsulated in the form of microcapsules(bio-polymeric beads).The cellulosic nanomaterials that used in this study were investigated as nanomaterials for wastewater treatment applications.Batch experiments were performed to study the removal of copper,lead,magnesium,and iron from aqueous solutions by the prepared beads.The effects of the sorbent dosage and the modified polymers on the removing efficiency of the metal cations were examined.Atomic absorption was used to measure the metal ions concentrations.The modified bio-polymeric beads(Alg-CNF,Alg-CNC,and Alg-TPC-CNF)exhibited high-efficiency towards removing of the metal cations;Cu^(2+),Pb^(2+),Mg^(2+),and Fe^(2+).The Alg-TPC-CNF composite was exhibited excellent removing efficiency which around 95%for Pb,92%for Cu,43%for Fe and 54%for Mg.These outcomes affirm that the utilization of nanomaterials giving higher adsorption capacities contrasted with similar material in its micro or macrostructure form.
基金This work was supported by the National Agency of Scientific and Technological Promotion(Grant No.PICT 2016-1611)the Santa Fe Province Agency of Science,Technology and Innovation(Grant No.AC 2015-0005)National University of Rosario(Grant No.BIO517).
基金the University of Nantes and the“Centre National de la Recherche Scientifique”(CNRS)for the financial supportthe“Ministère de l’Enseignement Supérieur et de la Recherche Scientifique de Cote d’Ivoire”for a grant
文摘The fabrication of a fully bio-sourced adsorbent of Cd(Ⅱ)by covalent immobilization of quinine on cellulose paper is described.The double bond of commercially available quinine was converted to a terminal alkyne function which was reacted with cellulose paper,chemically modified with azide functions,through a 1,3-dipolar cycloaddition,leading to Cell-Quin.The adsorption efficiency of Cell-Quin was investigated to determine the optimal pH,contact time and dose of adsorbent,ultimately leading to high levels of removal.The mechanism of adsorption of Cell-Quin was deeply rationalized through kinetic experiments and isotherm modeling.We also showed that Cell-Quin could adsorb other heavy metals such as Cu(Ⅱ),Pb(Ⅱ),Ni(Ⅱ)and Zn(Ⅱ).
基金supported by the 2016 Key Program of China Guodian Corporation,and the grant number is2015G1PU00200
文摘A new route to prepare zeolitic material was introduced in this work. Compared with traditional methods, the new route showed lower energy consume. The effect of pre-treatment conditions on structure and crystalline phase was investigated, revealing that the mullite crystalline phase in fly ash could be converted to amorphous phase by alkali at low temperature. The removal performance of heavy metal ions on designed material was also investigated, and we found that the intermediate product showed higher adsorption capacity on Ni^(2+) than zeolite A.
文摘Physical separation apparatuses;a vibrating screen, a 4-inch hydrocyclone and a Multi-Gravity Separator (MGS) were used to recover phosphorus as MAP (magnesium ammonium phosphate, MgNH<sub>4</sub>PO<sub>4.</sub>6H<sub>2</sub>O) from anaerobic digested sludge of two sewage-treatment plants A and B. For plant A, the MAP grade increased from 0.08% to 88.9% with 90.4% recovery and for plant B, the grade increased from 0.11% to 73.8 with 93.2% recovery. The collected MAP products containing impurities such as organic materials and heavy metals were further upgraded through dry and wet magnetic separation tests at different magnetic flux densities. A dry magnetic separator was tested on both MAP products (MAP-A and MAP-B), while the wet magnetic separation process was exclusively experimented for the removal of impurities from MAP-B. Feed samples, as well as magnetic and nonmagnetic products were analyzed by absorption spectroscopy, XRD, ICP-AES, polarizing microscope observation, and SEM-EDX. The grade of MAP products could be improved by about 4% - 9% after magnetic separation (the most appropriate magnetic force being 15,000 Gauss). During both dry and wet magnetic separation processes, not only heavy metals have been removed, but also nonmagnetic constituents like Al, Ba, and Ca. This may be attributed to the attachment of fine magnetic particles on the nonmagnetic surfaces, rendering them magnetic properties.
