Comparative experiments and theoretical analysis of the surface chemistry changes of goethite(GT)and goethite containing Ni(GTN)in the lattice in the presence of salicylhydroxamic acid(SA)were performed.It was reveale...Comparative experiments and theoretical analysis of the surface chemistry changes of goethite(GT)and goethite containing Ni(GTN)in the lattice in the presence of salicylhydroxamic acid(SA)were performed.It was revealed that in the presence of 100 g·t^(-1)of SA,the flotation recovery of GTN and GT increased with increasing pH,achieving a maximum recovery of 98.9%for both minerals at p H 8.3 and decreasing beyond that pH,with GTN having a slightly higher recovery than GT,except at pH 8.3.This was further confirmed by the higher complexation energies of GTN···SA(-883.87 kJ·mol^(-1))compared with GT···SA(-604.23 kJ·mol^(-1))resulting from covalent,closed-shell,and conventional hydrogen bonding.The higher adsorption of SA onto GTN relative to GT was due to the formation of aπ-hole in GTN,thereby promoting a higher interaction of the collector with the mineral.Thus,the presence of Ni in the GT lattice improves and decreases the adsorption and desorption of SA onto and from the mineral,respectively,compared with those onto and from GT.展开更多
Dimethyl ether(DME) is a widely used industrial compound, and Shell developed a chemical EOR technique called DMEenhanced waterflood(DEW). DME is applied as a miscible solvent for EOR application to enhance the perfor...Dimethyl ether(DME) is a widely used industrial compound, and Shell developed a chemical EOR technique called DMEenhanced waterflood(DEW). DME is applied as a miscible solvent for EOR application to enhance the performance of conventional waterflood. When DME is injected into the reservoir and contacts the oil, the first-contact miscibility process occurs, which leads to oil swelling and viscosity reduction. The reduction in oil density and viscosity improves oil mobility and reduces residual oil saturation, enhancing oil production. A numerical study based on compositional simulation has been developed to describe the phase behavior in the DEW model. An accurate compositional model is imperative because DME has a unique advantage of solubility in both oil and water. For DEW, oil recovery increased by 34% and 12% compared to conventional waterflood and CO_2 flood, respectively. Compositional modeling and simulation of the DEW process indicated the unique solubility effect of DME on EOR performance.展开更多
Polymers play an important role in hybrid enhanced oil recovery (EOR), which involves both a polymer and low-salinity water. Because the polymer commonly used for low-salinity polymer flooding (LSPF) is strongly sensi...Polymers play an important role in hybrid enhanced oil recovery (EOR), which involves both a polymer and low-salinity water. Because the polymer commonly used for low-salinity polymer flooding (LSPF) is strongly sensitive to brine pH, its efficiency can deteriorate in carbonate reservoirs containing highly acidic formation water. In this study, polymer efficiency in an acidic carbonate reservoir was investigated experimentally for different salinity levels and SO42− concentrations. Results indicated that lowering salinity improved polymer stability, resulting in less polymer adsorption, greater wettability alteration, and ultimately, higher oil recovery. However, low salinity may not be desirable for LSPF if the injected fluid does not contain a sufficient number of sulfate (SO42−) ions. Analysis of polymer efficiency showed that more oil can be produced with the same polymer concentration by adjusting the SO42− content. Therefore, when river water, which is relatively easily available in onshore fields, is designed to be injected into an acidic carbonate reservoir, the LSPF method proposed in this study can be a reliable and environmentally friendly method with addition of a sufficient number of SO42− ions to river water.展开更多
When low-salinity water containing sulfate ions is injected into carbonate reservoirs, rock dissolution and in situ precipitation occur, altering rock permeability and wettability. Particularly, when barium ions are p...When low-salinity water containing sulfate ions is injected into carbonate reservoirs, rock dissolution and in situ precipitation occur, altering rock permeability and wettability. Particularly, when barium ions are present in formation water,they react chemically with SO_4^(-2), and BaSO_4 is precipitated. These reactions can cause a serious impact on the efficiency of enhanced oil recovery(EOR). Therefore, the main purpose of this study was to identify EOR efficiency induced by lowsalinity waterflooding(LSWF) when Ba^(2+) is present in carbonate reservoirs. From the experimental results, it was confirmed that the permeability calculated by the measured pressure difference was improved because of rock dissolution predominating over in situ precipitation for the case of low Ba^(2+) concentrations. In the analysis of wettability alteration through the measurements of relative permeabilities before and after LSWF, the higher Ba^(2+) concentration case consumed more SO_4^(-2) in precipitating the BaSO_4, resulting in weaker wettability alteration due to the reduction of sulfate activity.These phenomena ultimately influenced EOR efficiency, i.e., the oil recovery was greater for the lower Ba^(2+) concentration.展开更多
Although low salinity water injection(LSWI) has recovered residual oil after the conventional waterflood, highly viscous oil has remained in heavy oil reservoirs. Hot water injection is an economic and practical metho...Although low salinity water injection(LSWI) has recovered residual oil after the conventional waterflood, highly viscous oil has remained in heavy oil reservoirs. Hot water injection is an economic and practical method to improve oil mobility for viscous oil reservoirs. It potentially controls temperature-dependent geochemical reactions underlying the LSWI mechanism and oil viscosity. Therefore, this study has modeled and evaluated a hybrid process of low salinity hot water injection(hot LSWI) to quantify synergistic effects in heavy oil reservoirs. In comparison to seawater injection(SWI) and LSWI, hot LSWI results in more cation ion-exchange(Ca^(2+) and Mg^(2+)) and more wettability modification. Hot LSWI also reduces oil viscosity. In core-scaled systems, it increases oil recovery by 21% and 6% over SWI and LSWI. In a pilotscaled reservoir, it produces additional oil by 6% and 3% over SWI and LSWI. Probabilistic forecasting with uncertainty assessment further evaluates the feasibility of hot LSWI to consider uncertainty in the pilot-scaled reservoir and observes enhanced heavy oil production. This study confirms the viability of hot LSWI due to synergistic effects including enhanced wettability modification and oil viscosity reduction effects.展开更多
Biochar(BC)has gained attention for removal of toxic elements(TEs)from aqueous media;however,pristine biochar often exhibits low adsorption capability.Thus,various modification strategies in BC have been developed to ...Biochar(BC)has gained attention for removal of toxic elements(TEs)from aqueous media;however,pristine biochar often exhibits low adsorption capability.Thus,various modification strategies in BC have been developed to improve its removal capability against TEs.Nanoscale zero-valent iron(nZVI)and iron oxides(FeOx)have been used as sorbents for TE removal.However,these materials are prone to agglomeration and also expensive,which make their usage limited for large-scale applications.The nZVI technical demerits could be resolved by the development of BC-based composite sorbents through the loading of nZVI or FeOx onto BC surface.Nano zero-valent iron modified BC(nZVIBC),FeOx-modified BC(FeOxBC)have attracted attention for their capability in removing pollutants from the aqueous phases.Nonetheless,a potential use of nZVIBC and FeOxBC for TE removal from aqueous environments has not been well-realized or reviewed.As such,this article reviews:(i)the preparation and characterization of nZVIBC and FeOxBC;(ii)the capacity of nZVIBC and FeOxBC for TE retention in line with their physicochemical properties,and(iii)TE removal mechanisms by nZVIBC and FeOxBC.Adopting nZVI and FeOx in BC increases its sporptive capability of TEs due to surface modifications in morphology,functional groups,and elemental composition.The combined effects of BC and nZVI,FeOx or Fe salts on the sorption of TEs are complex because they are very specific to TEs.This review identified significant opportunities for research and technol-ogy advancement of nZVIBC and FeOxBC as novel and effective sorbents for the remediation of TEs contaminated water.展开更多
The present study investigated the efficiency of Aspergillus sydowii strain bpol(GenBank Accession Number:MK373021)in the removal of anthracene(100 mg/L).Optimal degradation efficiency(98.7%)was observed at neutral pH...The present study investigated the efficiency of Aspergillus sydowii strain bpol(GenBank Accession Number:MK373021)in the removal of anthracene(100 mg/L).Optimal degradation efficiency(98.7%)was observed at neutral pH,temperature(30℃),biomass weight(2 g)and salinity(0.2%w/v)within 72 h.The enzyme analyses revealed 131%,107%,and 89%induction in laccase,lignin peroxidase,and manganese peroxidase respectively during anthracene degradation.Furthermore,the degradation efficiency(99.8%)and enzyme induction were significantly enhanced with the addition of 100 mg/L of citric acid and glucose to the culture.At varying anthracene concentrations(100-500 mg/L),the degradation rate constants(K1)peaked with increasing concentration of anthracene while the half-life(t1/2)decreases with increase in anthracene concentration.Goodness of fit(R2=0.976 and 0.982)was observed when the experimental data were subjected to Langmuir and Temkin models respectively which affirmed the monolayer and heterogeneous nature exhibited by A.sydwoii cells during degradation.Four distinct metabolites;anthracene-1,8,9(2H,8aH,9aH)-trione,2,4adihydronaphthalene-1,5-dione,l,3,3a,7a-tetrahydro-2-benzofuran-4,7-dione and 2-hydroxybenzoic acid was obtained through Gas Chromatography-Mass spectrometry(GC-MS).A.sydowii exhibited promising potentials in the removal of PAHs.展开更多
Sewage sludge(SS)is a residual/semi-solid material produced from industrial and municipal wastewater treatment processes.SS contains a high content of lipids and earth alkaline metals that can be used as catalysts for...Sewage sludge(SS)is a residual/semi-solid material produced from industrial and municipal wastewater treatment processes.SS contains a high content of lipids and earth alkaline metals that can be used as catalysts for various chemical applications;however,its valorization has rarely been the focus of research.This study demonstrates that SS could be a promising raw material for biodiesel production and a biochar catalyst to promote the reaction kinetics of alkylation.Thermally induced transesterification of the SS extract(SSE)was performed in comparison with the conventional homogeneous reaction.SS biochar was fabricated via pyrolysis.The highest yield(33.5 wt.%per SSE)of biodiesel production was achieved in 1 min of reaction at 305℃via thermally induced transesterification in the presence of SS biochar,while the yield of biodiesel from(trans)esterification with 5 wt.%H_(2)SO_(4)was less than 1%even after 24 h.The reaction kinetics(<1 min)of thermally induced transesterification was extraordinarily faster than that of conventional transesterification(3-24 h).The porous structure and high content of alkaline species in the SS biochar expedited the reaction kinetics.Consequently,the integrated/hybridized process for thermally induced transesterification and pyrolysis of the solid residue of SS was experimentally proved for the valorization of SS in this study.Considering that SS is being disposed of as a waste material and generates toxic chemicals in the environment,its valorization into value-added biodiesel and a catalyst could be an environmentally benign and sustainable technique.展开更多
基金supported by the Korea Institute of Energy Technology Evaluation and Planning(KETEP)and the Ministry of Trade,Industry&Energy(MOTIE)of the Republic of Korea(No.20227A10100010)。
文摘Comparative experiments and theoretical analysis of the surface chemistry changes of goethite(GT)and goethite containing Ni(GTN)in the lattice in the presence of salicylhydroxamic acid(SA)were performed.It was revealed that in the presence of 100 g·t^(-1)of SA,the flotation recovery of GTN and GT increased with increasing pH,achieving a maximum recovery of 98.9%for both minerals at p H 8.3 and decreasing beyond that pH,with GTN having a slightly higher recovery than GT,except at pH 8.3.This was further confirmed by the higher complexation energies of GTN···SA(-883.87 kJ·mol^(-1))compared with GT···SA(-604.23 kJ·mol^(-1))resulting from covalent,closed-shell,and conventional hydrogen bonding.The higher adsorption of SA onto GTN relative to GT was due to the formation of aπ-hole in GTN,thereby promoting a higher interaction of the collector with the mineral.Thus,the presence of Ni in the GT lattice improves and decreases the adsorption and desorption of SA onto and from the mineral,respectively,compared with those onto and from GT.
基金supported by the Energy Efficiency & Resources Core Technology Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) of the Ministry of Trade, Industry, & Energy, Republic of Korea (No. 20152520100760)
文摘Dimethyl ether(DME) is a widely used industrial compound, and Shell developed a chemical EOR technique called DMEenhanced waterflood(DEW). DME is applied as a miscible solvent for EOR application to enhance the performance of conventional waterflood. When DME is injected into the reservoir and contacts the oil, the first-contact miscibility process occurs, which leads to oil swelling and viscosity reduction. The reduction in oil density and viscosity improves oil mobility and reduces residual oil saturation, enhancing oil production. A numerical study based on compositional simulation has been developed to describe the phase behavior in the DEW model. An accurate compositional model is imperative because DME has a unique advantage of solubility in both oil and water. For DEW, oil recovery increased by 34% and 12% compared to conventional waterflood and CO_2 flood, respectively. Compositional modeling and simulation of the DEW process indicated the unique solubility effect of DME on EOR performance.
基金supported by the Energy Efficiency&Resources(No.20212010200010)the“Development of Intelligential Diagnosis,Abandonment Process and Management Technology for Decrepit Oil and Gas Wells”(No.20216110100010)of the Korea Institute of Energy Technology EvaluationPlanning(KETEP)grant funded by the Korean Government Ministry of Trade,Industry&Energy.
文摘Polymers play an important role in hybrid enhanced oil recovery (EOR), which involves both a polymer and low-salinity water. Because the polymer commonly used for low-salinity polymer flooding (LSPF) is strongly sensitive to brine pH, its efficiency can deteriorate in carbonate reservoirs containing highly acidic formation water. In this study, polymer efficiency in an acidic carbonate reservoir was investigated experimentally for different salinity levels and SO42− concentrations. Results indicated that lowering salinity improved polymer stability, resulting in less polymer adsorption, greater wettability alteration, and ultimately, higher oil recovery. However, low salinity may not be desirable for LSPF if the injected fluid does not contain a sufficient number of sulfate (SO42−) ions. Analysis of polymer efficiency showed that more oil can be produced with the same polymer concentration by adjusting the SO42− content. Therefore, when river water, which is relatively easily available in onshore fields, is designed to be injected into an acidic carbonate reservoir, the LSPF method proposed in this study can be a reliable and environmentally friendly method with addition of a sufficient number of SO42− ions to river water.
基金supported by a Grant as part of the ‘‘Development of IOR/EOR technologies and field verification for carbonate reservoirs in UAE’’ project by the Korean Government Ministry of Trade,Industry and Energy (MOTIE).(No. 20152510101980)
文摘When low-salinity water containing sulfate ions is injected into carbonate reservoirs, rock dissolution and in situ precipitation occur, altering rock permeability and wettability. Particularly, when barium ions are present in formation water,they react chemically with SO_4^(-2), and BaSO_4 is precipitated. These reactions can cause a serious impact on the efficiency of enhanced oil recovery(EOR). Therefore, the main purpose of this study was to identify EOR efficiency induced by lowsalinity waterflooding(LSWF) when Ba^(2+) is present in carbonate reservoirs. From the experimental results, it was confirmed that the permeability calculated by the measured pressure difference was improved because of rock dissolution predominating over in situ precipitation for the case of low Ba^(2+) concentrations. In the analysis of wettability alteration through the measurements of relative permeabilities before and after LSWF, the higher Ba^(2+) concentration case consumed more SO_4^(-2) in precipitating the BaSO_4, resulting in weaker wettability alteration due to the reduction of sulfate activity.These phenomena ultimately influenced EOR efficiency, i.e., the oil recovery was greater for the lower Ba^(2+) concentration.
基金financially supported by the Energy Efficiency and Resources of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) Grant funded by the Korea government Ministry of Knowledge Economy (No. 20172510102290)
文摘Although low salinity water injection(LSWI) has recovered residual oil after the conventional waterflood, highly viscous oil has remained in heavy oil reservoirs. Hot water injection is an economic and practical method to improve oil mobility for viscous oil reservoirs. It potentially controls temperature-dependent geochemical reactions underlying the LSWI mechanism and oil viscosity. Therefore, this study has modeled and evaluated a hybrid process of low salinity hot water injection(hot LSWI) to quantify synergistic effects in heavy oil reservoirs. In comparison to seawater injection(SWI) and LSWI, hot LSWI results in more cation ion-exchange(Ca^(2+) and Mg^(2+)) and more wettability modification. Hot LSWI also reduces oil viscosity. In core-scaled systems, it increases oil recovery by 21% and 6% over SWI and LSWI. In a pilotscaled reservoir, it produces additional oil by 6% and 3% over SWI and LSWI. Probabilistic forecasting with uncertainty assessment further evaluates the feasibility of hot LSWI to consider uncertainty in the pilot-scaled reservoir and observes enhanced heavy oil production. This study confirms the viability of hot LSWI due to synergistic effects including enhanced wettability modification and oil viscosity reduction effects.
文摘Biochar(BC)has gained attention for removal of toxic elements(TEs)from aqueous media;however,pristine biochar often exhibits low adsorption capability.Thus,various modification strategies in BC have been developed to improve its removal capability against TEs.Nanoscale zero-valent iron(nZVI)and iron oxides(FeOx)have been used as sorbents for TE removal.However,these materials are prone to agglomeration and also expensive,which make their usage limited for large-scale applications.The nZVI technical demerits could be resolved by the development of BC-based composite sorbents through the loading of nZVI or FeOx onto BC surface.Nano zero-valent iron modified BC(nZVIBC),FeOx-modified BC(FeOxBC)have attracted attention for their capability in removing pollutants from the aqueous phases.Nonetheless,a potential use of nZVIBC and FeOxBC for TE removal from aqueous environments has not been well-realized or reviewed.As such,this article reviews:(i)the preparation and characterization of nZVIBC and FeOxBC;(ii)the capacity of nZVIBC and FeOxBC for TE retention in line with their physicochemical properties,and(iii)TE removal mechanisms by nZVIBC and FeOxBC.Adopting nZVI and FeOx in BC increases its sporptive capability of TEs due to surface modifications in morphology,functional groups,and elemental composition.The combined effects of BC and nZVI,FeOx or Fe salts on the sorption of TEs are complex because they are very specific to TEs.This review identified significant opportunities for research and technol-ogy advancement of nZVIBC and FeOxBC as novel and effective sorbents for the remediation of TEs contaminated water.
基金Bankole Paul Olusegun hereby thank the Association of Commonwealth Universities(ACU)for the 2019 Blue Charter Award.
文摘The present study investigated the efficiency of Aspergillus sydowii strain bpol(GenBank Accession Number:MK373021)in the removal of anthracene(100 mg/L).Optimal degradation efficiency(98.7%)was observed at neutral pH,temperature(30℃),biomass weight(2 g)and salinity(0.2%w/v)within 72 h.The enzyme analyses revealed 131%,107%,and 89%induction in laccase,lignin peroxidase,and manganese peroxidase respectively during anthracene degradation.Furthermore,the degradation efficiency(99.8%)and enzyme induction were significantly enhanced with the addition of 100 mg/L of citric acid and glucose to the culture.At varying anthracene concentrations(100-500 mg/L),the degradation rate constants(K1)peaked with increasing concentration of anthracene while the half-life(t1/2)decreases with increase in anthracene concentration.Goodness of fit(R2=0.976 and 0.982)was observed when the experimental data were subjected to Langmuir and Temkin models respectively which affirmed the monolayer and heterogeneous nature exhibited by A.sydwoii cells during degradation.Four distinct metabolites;anthracene-1,8,9(2H,8aH,9aH)-trione,2,4adihydronaphthalene-1,5-dione,l,3,3a,7a-tetrahydro-2-benzofuran-4,7-dione and 2-hydroxybenzoic acid was obtained through Gas Chromatography-Mass spectrometry(GC-MS).A.sydowii exhibited promising potentials in the removal of PAHs.
基金National Research Foundation of Korea(NRF)Grant funded by the Korean government(MSIT)(NRF-2020R1A2C1010748).
文摘Sewage sludge(SS)is a residual/semi-solid material produced from industrial and municipal wastewater treatment processes.SS contains a high content of lipids and earth alkaline metals that can be used as catalysts for various chemical applications;however,its valorization has rarely been the focus of research.This study demonstrates that SS could be a promising raw material for biodiesel production and a biochar catalyst to promote the reaction kinetics of alkylation.Thermally induced transesterification of the SS extract(SSE)was performed in comparison with the conventional homogeneous reaction.SS biochar was fabricated via pyrolysis.The highest yield(33.5 wt.%per SSE)of biodiesel production was achieved in 1 min of reaction at 305℃via thermally induced transesterification in the presence of SS biochar,while the yield of biodiesel from(trans)esterification with 5 wt.%H_(2)SO_(4)was less than 1%even after 24 h.The reaction kinetics(<1 min)of thermally induced transesterification was extraordinarily faster than that of conventional transesterification(3-24 h).The porous structure and high content of alkaline species in the SS biochar expedited the reaction kinetics.Consequently,the integrated/hybridized process for thermally induced transesterification and pyrolysis of the solid residue of SS was experimentally proved for the valorization of SS in this study.Considering that SS is being disposed of as a waste material and generates toxic chemicals in the environment,its valorization into value-added biodiesel and a catalyst could be an environmentally benign and sustainable technique.
