The low-density medium-Mn steel is widely studied and applied in the automobile and construction machinery due to the low costs and high strength-ductility.Adding lightweight elements,such as aluminum,is considered an...The low-density medium-Mn steel is widely studied and applied in the automobile and construction machinery due to the low costs and high strength-ductility.Adding lightweight elements,such as aluminum,is considered an efficient way to reduce the density of the steels.A novel 5Al-5Mn-1.5Si-0.3C(wt%)low-density and high-strengthδ-ferrite/martensite(δ-F/M)steel was designed in this study.The study indicated that the designed steel annealed at 1080℃was characterized by an excellent combination of tensile strength of 1246 MPa and density of 7.24 g/cm^(3).Microscopic characterization shows that the higher prior-austenite volume fraction(i.e.,martensite plus retained austenite)significantly increases the tensile strength,and the strip-like martensite and retained austenite(M&RA)mixture benefits elongation.High martensite fraction owns higher origin geometrically necessary dislocations,contributing to better work-hardening behaviors.Concurrently,the synergistic presence of M&RA mixtures’volume fraction and morphology enhances their capability to absorb stress and obstruct crack propagation,significantly improving mechanical performance.The extended strength formula,accounting for the contribution of the M&RA mixture,is consistent with the quantitative agreement observed in experimental results.These insights provide a valuable technological reference for the knowledge-based design and prediction of the mechanical properties of low-density and high-strength steel.展开更多
Iron-rich electrolytic manganese residue(IREMR)is an industrial waste produced during the processing of electrolytic metal manganese,and it contains certain amounts of Fe and Mn resources and other heavy metals.In thi...Iron-rich electrolytic manganese residue(IREMR)is an industrial waste produced during the processing of electrolytic metal manganese,and it contains certain amounts of Fe and Mn resources and other heavy metals.In this study,the slurry electrolysis technique was used to recover high-purity Fe powder from IREMR.The effects of IREMR and H2SO4 mass ratio,current density,reaction temper-ature,and electrolytic time on the leaching and current efficiencies of Fe were studied.According to the results,high-purity Fe powder can be recovered from the cathode plate,and the slurry electrolyte can be recycled.The leaching efficiency,current efficiency,and purity of Fe reached 92.58%,80.65%,and 98.72wt%,respectively,at a 1:2.5 mass ratio of H2SO4 and IREMR,reaction temperature of 60℃,electric current density of 30 mA/cm^(2),and reaction time of 8 h.In addition,vibrating sample magnetometer(VSM)analysis showed that the coercivity of electrolytic iron powder was 54.5 A/m,which reached the advanced magnetic grade of electrical pure-iron powder(DT4A coercivity standard).The slurry electrolytic method provides fundamental support for the industrial application of Fe resource recovery in IRMER.展开更多
To address the hazardous by-product of zinc smelting and resource utilization of jarosite residue,this study applies an electric field-assisted hot acid treatment to completely recycle iron(Fe).This innovative approac...To address the hazardous by-product of zinc smelting and resource utilization of jarosite residue,this study applies an electric field-assisted hot acid treatment to completely recycle iron(Fe).This innovative approach aims to enhance the leaching efficiency of Fe from jarosite residue.The introduction of an electric field changes the charge distribution on the surface of the particles to enhance ions and electrons exchange and promotes the collision between particles to strengthen reaction kinetics.Based on the above,the leaching efficiency of Fe in jarosite under sulfuric acid attack has improved observably.The result shows that Fe leaching efficiency reaches 98.83%,which is increased by 28%under the optimal experimental conditions:current density of 30 mA·cm^(-2),H_(2)SO_(4) concentration of 1.5 mol·L^(-1),solid-liquid ratio of 70 g·L^(-1),temperature of 80℃ and time of 12 h.Leaching kinetics calculations show that the apparent activation energy is 16.97 kJ·mol^(-1) and the leaching of jarosite residue is controlled by a mixture of chemical reaction and diffusion,as well as the temperature and concentration of the leaching solution have an influence on leaching.This work provides a feasible idea for the efficient leaching of Fe from jarosite residue.展开更多
Grouting is the most commonly used method to control water inrush in underground engineering.Traditional cement-based materials are easy to dilute and hard to coagulate under the influence of large flow and high-veloc...Grouting is the most commonly used method to control water inrush in underground engineering.Traditional cement-based materials are easy to dilute and hard to coagulate under the influence of large flow and high-velocity water inrush.To address these deficiencies,a new type of polymer grouting material with an excellent expansion ratio was synthesised.The material quickly absorbs water and has an expansion ratio of 1:300.The material is composed of a superabsorbent polymer(SAP),glycerol,and ethanol.The effects of water quality on the expansion ratio and expansion rate of the material were examined,and the best solid–liquid ratio for the slurry was determined by fluidity measurements.A karst specially designed pipeline water inrush test device showed that 800 g of SAP can achieve 0.6 m/s water flow blockage in the smooth pipeline,demonstrating that the ability of the SAP slurry to block water inrush is superior to those of other materials.This study provides a reference for water inrush plugging,and has important implications for the reduction and control of karst pipeline-type water inrush disasters,ensuring the safety of construction sites and preventing loss of life and damage to property.展开更多
[Objectives] This study was conducted to establish an LC-MS/MS method for the determination of three kinds of polyether residues in eggs with QuEChERS dSPE EMR-Lipid as a pretreatment method, which was established acc...[Objectives] This study was conducted to establish an LC-MS/MS method for the determination of three kinds of polyether residues in eggs with QuEChERS dSPE EMR-Lipid as a pretreatment method, which was established according to Agilent Bond Elut enhanced lipid removal EMR-Lipid technology. [ Methods] Egg was extracted by acidified acetonitrile, purified by Bond Elut EMR-Lipid QuEChERS, and detected by HPLC-MS/MS. [ Results] The three kinds of polyether residues had good linear relationships in the range of 2.0 - 100 μg/L with peak areas, r 〉 0. 999. The recoveries ranged from 84.6% to 107.0%. [ Conclusions ] The method is convenient and accurate, and the quantitative results are accurate and reproducible. It is suitable for the determination of the three kinds of polyether residues in eggs.展开更多
Recently a new grout material called water inflow sealing(WIS) was invented for sealing water inflow in tunneling and underground constructions. In this study, a special experimental method called intubated counter gr...Recently a new grout material called water inflow sealing(WIS) was invented for sealing water inflow in tunneling and underground constructions. In this study, a special experimental method called intubated counter grouting(ICG) was proposed to investigate the influence of water dispersion on the rheological properties of the grout during the grouting process, and to testify the sealing performance of the grout,such as instant gelling ability(IGA) and anti-dispersion ability(ADA). In the experiment, dispersion was restricted in the downstream of the channel with a high turbulence intensity. The influences of ADA and IGA were therefore decoupled and evaluated separately. Experimental results revealed two distinctive sealing mechanisms of WIS. For a low initial velocity of water, WIS turned the shear flow of water into an overall movement of a plug by absorbing water into the particles. For a high initial velocity and the situation that the particles reached the outlet before sufficiently expanding, WIS modified the rheology of the water in the channel and reduced its velocity till the static state. The distinctive feature of WIS brings a reformation on the sealing mechanism and provides an effective way to control water inflow with high pressure and velocity.展开更多
[Objectives] To establish Qu ECh ERS based extraction method for determining multiple pesticide residues in okra combined with programmed temperature vaporizer-gas chromatography-triple quadrupole mass spectrometry( P...[Objectives] To establish Qu ECh ERS based extraction method for determining multiple pesticide residues in okra combined with programmed temperature vaporizer-gas chromatography-triple quadrupole mass spectrometry( PTV-GC-MS/MS) and ultra high performance liquid chromatography-mass spectrometry( UPLC-MS/MS). [Methods] In this experiment,124 pesticide residues in okra were determined by an optimized Qu ECh ERS method combined with PTV-GC-MS/MS and UPLC-MS/MS. The pesticides in okra were extracted and purified by the optimized Qu ECh ERS pretreatment method and determined by PTV-GC-MS/MS and UPLC-MS/MS. [Results] In this experiment,124 kinds of pesticides had a good linearity with a limit of detection( LOD) of 0. 000 5-0. 008 0 mg/kg; the average recovery rate at three levels was 65. 5%-128. 1% with relative standard deviation of 2. 2%-9. 7%. [Conclusions] This method is simple,rapid,accurate and sensitive,and can provide reliable and valid data support for the determination of multiple pesticide residues in okra by GC-MS/MS and UPLC-MS/MS.展开更多
Electrolytic manganese metal residue(EMMR)harmless treatment has always lacked a low-cost and quick processing technology.In this study,surfactants,namely tetradecyl trimethylammonium chloride(TTC),sodium dodecyl benz...Electrolytic manganese metal residue(EMMR)harmless treatment has always lacked a low-cost and quick processing technology.In this study,surfactants,namely tetradecyl trimethylammonium chloride(TTC),sodium dodecyl benzene sulfonate(SDBS),sodium lignin sulfonate(SLS),and octadecyl trimethylammonium chloride(OTC),were used in the solidification of Mn^(2+)and removal of NH_(4)^(+)-N from EMMR.The Mn^(2+)and NH_(4)^(+)-N concentrations under different reaction conditions,Mn^(2+)solidification and NH_(4)^(+)-N removal mechanisms,and leaching behavior were studied.The results revealed that the surfactants could enhance the Mn^(2+)solidification and NH_(4)^(+)-N removal from EMMR,and the order of enhancement was as follows:TTC>SDBS>OTC>SLS.The NH_(4)^(+)-N and Mn^(2+)concentrations were 12.3 and 0.05 mg·L^(-1)with the use of 60.0 mg·kg^(-1)TTC under optimum conditions(solid–liquid ratio of 1.5:1,EMMR to BRM mass ratio of 100:8,temperature of 20℃,and reaction duration of 12 h),which met the integrated wastewater discharge standard(GB8978-1996).Mn^(2+)was mainly solidified as Mn(OH)_(2),MnOOH and MnSiO_(3),and NH_(4)^(+)-N in EMMR was mostly removed in the form of ammonia.The results of this study could provide a new idea for cost-effective EMMR harmless treatment.展开更多
Spent lead paste(SLP)presents a major recycling challenge in lead-acid battery treatment due to its insoluble lead compounds.This study develops an innovative and environmentally sustainable approach by integrating(NH...Spent lead paste(SLP)presents a major recycling challenge in lead-acid battery treatment due to its insoluble lead compounds.This study develops an innovative and environmentally sustainable approach by integrating(NH_(4))_(2)SO_(4)-NH_(3)·H_(2)O with suspension electrolysis,effectively converting poorly soluble PbSO_(4)into soluble[Pb(NH_(3))_(4)]^(2+)complexes.The electrolytic conversion mechanisms of SLP components are systematically elucidated,revealing four distinct transformation pathways:1)metallic Pb undergoes complete dissolution as[Pb(NH_(3))_(4)]^(2+)complexes followed by cathodic reduction to elemental lead;2)PbO_(2)increases after suspension electrolysis since part of PbO is oxidized;3)PbO demonstrates dual behavior,with 45.74%undergoing anodic oxidation to PbO_(2) while the remainder(54.26%)participates in cathodic electrodeposition;4)PbSO_(4)exhibits triple conversion routes,including:1)32.98%transformation through intermediate(NH_(4))Pb(OH)SO_(4)formation followed by anodic conversion to PbO·PbSO_(4),2)21.36%direct cathodic reduction to metallic lead,and 3)the residual fraction maintaining soluble[Pb(NH_(3))_(4)]^(2+)speciation in the electrolyte.The optimized process achieves exceptional current efficiency(95.49%)and lead recovery(45.67%),with anode residues comprising 67.58%PbO_(2)and 32.42%PbO·PbSO_(4).Remarkably,this process exhibits significant economic and environmental advantages,with recycling 1 kg of SLP through the(NH_(4))_(2)SO_(4)-NH_(3)·H_(2)O suspension electrolysis process resulting in a net profit of 0.3466 USD and a reduction in carbon emissions of 119.758 kg CO_(2)eq.,offering dual advantages of environmental and economic benefits.This work provides fundamental insights into lead phase conversion during suspension electrolysis while presenting a practical,effective solution for battery recycling industries.展开更多
The concept of zero waste is an ideal situation that will require different solutions for different categories of waste.Electronic waste(E-waste),the fastest growing category of solid hazardous waste presents various ...The concept of zero waste is an ideal situation that will require different solutions for different categories of waste.Electronic waste(E-waste),the fastest growing category of solid hazardous waste presents various unique challenges.Electronic product repair,reuse and remanufacture(3re)are crucial for effective source reduction of E-waste and the integration of the electronics industry into a circular or zero-waste economy framework.Increasingly,3re implementation is restricted by regulatory difficulties,particularly the invocation of copyright laws.Here,we use the examples of electronic printer cartridges and restored compact discs(CDs)to identify the challenges and to explore solutions for managing the risks associated with E-waste through circular economy and the opportunities presented by innovative Blockchain solutions.A set of international consensuses on judicial definitions,such as 3re,refurbish fake/counterfeit product and copyright exhaustion,are proposed to accelerate source reduction in E-waste management toward the goal of zero waste.展开更多
Copper recovery is the core of waste printed circuit boards （WPCBs） treatment. In this study, we proposed a feasible and efficient way to recover copper from WPCBs concentrated metal scraps by direct electrolysis an...Copper recovery is the core of waste printed circuit boards （WPCBs） treatment. In this study, we proposed a feasible and efficient way to recover copper from WPCBs concentrated metal scraps by direct electrolysis and thctors that affect copper recovery rate and purity, mainly CuSO4.5H2O concentration, NaCI concentration, H2SO4 concentration and current density, were discussed in detail. The results indicated that copper recovery rate increased first with the increase ofCuSO4- 5H2O, NaCI, H2SO4 and current density and then decreased with further increasing these conditions. NaCI, H2SO4 and current density also showed a similar impact on copper purity, which also increased first and then decreased. Copper purity increased with the increase of CuSO4.5H2O. When the concentration of CuSO4-5H2O NaCI and H2oSO4 was respectively 90, 40 and 118 g/L and current density was 80 mA/cm-, copper recovery rate and purity was up to 97.32% and 99.86%, respectively. Thus, electrolysis proposes a feasible and prospective approach for waste printed circuit boards recycle, even for e-waste, though more researches are needed for industrial application.展开更多
Superfine copper particles could be directly prepared from waste printed circuit boards by slurry electrolysis.Meanwhile,copper fractal growth could be observed.To better understand this phenomenon,the factors that af...Superfine copper particles could be directly prepared from waste printed circuit boards by slurry electrolysis.Meanwhile,copper fractal growth could be observed.To better understand this phenomenon,the factors that affect copper dendrites in a point-cathode system were discussed in detail.These results showed that the fractal degree of copper dendrites increased as the increase of applied voltage and the decrease of copper sulfate and gelatin concentrations.Sodium lauryl sulfate and hydrochloric acid concentrations could not significantly impact the fractal degree of copper dendrites,while gelatin concentration could.The minimum copper fractal dimension was 1.069 when gelatin and copper sulfate concentration was 120 mg/L and 0.1 mol/L,respectively with an applied voltage of 11 V.Moreover,the results diffusion-limited aggregation model demonstrated that particle translational speed,particle numbers and binding probability significantly affected copper dendrite patterns.The scanning electron microscopy results indicated that the three additives greatly affected the refinement of the copper crystal.These findings contribute to enrich the theoretical study on metals recovery from e-waste by slurry electrolysis.展开更多
基金supported by the Key Research and Development Program of Hubei Province(No.2021BAA057)the National Natural Science Foundation of China(Nos.U20A20279,12174296 and 12102310)+5 种基金the Major Program(JD)of Hubei Province(No.2023BAA019-5)the Natural Science Foundation of Hubei Province(No.2022CFB474)the Science and Technology Program of Guangxi Province(No.AA22068080)the Taishan Industry Leading Talent Project(No.2020007)the Leading Innovation and Pioneering Team of Zhejiang Province(2021R01020)the 111 Project(No.D18018).
文摘The low-density medium-Mn steel is widely studied and applied in the automobile and construction machinery due to the low costs and high strength-ductility.Adding lightweight elements,such as aluminum,is considered an efficient way to reduce the density of the steels.A novel 5Al-5Mn-1.5Si-0.3C(wt%)low-density and high-strengthδ-ferrite/martensite(δ-F/M)steel was designed in this study.The study indicated that the designed steel annealed at 1080℃was characterized by an excellent combination of tensile strength of 1246 MPa and density of 7.24 g/cm^(3).Microscopic characterization shows that the higher prior-austenite volume fraction(i.e.,martensite plus retained austenite)significantly increases the tensile strength,and the strip-like martensite and retained austenite(M&RA)mixture benefits elongation.High martensite fraction owns higher origin geometrically necessary dislocations,contributing to better work-hardening behaviors.Concurrently,the synergistic presence of M&RA mixtures’volume fraction and morphology enhances their capability to absorb stress and obstruct crack propagation,significantly improving mechanical performance.The extended strength formula,accounting for the contribution of the M&RA mixture,is consistent with the quantitative agreement observed in experimental results.These insights provide a valuable technological reference for the knowledge-based design and prediction of the mechanical properties of low-density and high-strength steel.
基金supported by the Key Research and Development Program of Guangxi Province,China (No.AB23075174)the National Natural Science Foundation of China (No.52174386)the Science and Technology Plan Project of Sichuan Province,China (No.2022YFS0459).
文摘Iron-rich electrolytic manganese residue(IREMR)is an industrial waste produced during the processing of electrolytic metal manganese,and it contains certain amounts of Fe and Mn resources and other heavy metals.In this study,the slurry electrolysis technique was used to recover high-purity Fe powder from IREMR.The effects of IREMR and H2SO4 mass ratio,current density,reaction temper-ature,and electrolytic time on the leaching and current efficiencies of Fe were studied.According to the results,high-purity Fe powder can be recovered from the cathode plate,and the slurry electrolyte can be recycled.The leaching efficiency,current efficiency,and purity of Fe reached 92.58%,80.65%,and 98.72wt%,respectively,at a 1:2.5 mass ratio of H2SO4 and IREMR,reaction temperature of 60℃,electric current density of 30 mA/cm^(2),and reaction time of 8 h.In addition,vibrating sample magnetometer(VSM)analysis showed that the coercivity of electrolytic iron powder was 54.5 A/m,which reached the advanced magnetic grade of electrical pure-iron powder(DT4A coercivity standard).The slurry electrolytic method provides fundamental support for the industrial application of Fe resource recovery in IRMER.
基金The National Natural Science Foundation of China(22276153,51974262)funded this work。
文摘To address the hazardous by-product of zinc smelting and resource utilization of jarosite residue,this study applies an electric field-assisted hot acid treatment to completely recycle iron(Fe).This innovative approach aims to enhance the leaching efficiency of Fe from jarosite residue.The introduction of an electric field changes the charge distribution on the surface of the particles to enhance ions and electrons exchange and promotes the collision between particles to strengthen reaction kinetics.Based on the above,the leaching efficiency of Fe in jarosite under sulfuric acid attack has improved observably.The result shows that Fe leaching efficiency reaches 98.83%,which is increased by 28%under the optimal experimental conditions:current density of 30 mA·cm^(-2),H_(2)SO_(4) concentration of 1.5 mol·L^(-1),solid-liquid ratio of 70 g·L^(-1),temperature of 80℃ and time of 12 h.Leaching kinetics calculations show that the apparent activation energy is 16.97 kJ·mol^(-1) and the leaching of jarosite residue is controlled by a mixture of chemical reaction and diffusion,as well as the temperature and concentration of the leaching solution have an influence on leaching.This work provides a feasible idea for the efficient leaching of Fe from jarosite residue.
基金the financial supports from National Key Research and Development Project(No.2019YFC1805402)National Natural Science Foundation of China(Nos.U1906229 and U1706223)Project supported by the Science Fund for Creative Research Groups of the National Natural Science Foundation of China(No.52021005)。
文摘Grouting is the most commonly used method to control water inrush in underground engineering.Traditional cement-based materials are easy to dilute and hard to coagulate under the influence of large flow and high-velocity water inrush.To address these deficiencies,a new type of polymer grouting material with an excellent expansion ratio was synthesised.The material quickly absorbs water and has an expansion ratio of 1:300.The material is composed of a superabsorbent polymer(SAP),glycerol,and ethanol.The effects of water quality on the expansion ratio and expansion rate of the material were examined,and the best solid–liquid ratio for the slurry was determined by fluidity measurements.A karst specially designed pipeline water inrush test device showed that 800 g of SAP can achieve 0.6 m/s water flow blockage in the smooth pipeline,demonstrating that the ability of the SAP slurry to block water inrush is superior to those of other materials.This study provides a reference for water inrush plugging,and has important implications for the reduction and control of karst pipeline-type water inrush disasters,ensuring the safety of construction sites and preventing loss of life and damage to property.
基金Supported by Science and Technology Planning Project of Huizhou City(20161117141959)
文摘[Objectives] This study was conducted to establish an LC-MS/MS method for the determination of three kinds of polyether residues in eggs with QuEChERS dSPE EMR-Lipid as a pretreatment method, which was established according to Agilent Bond Elut enhanced lipid removal EMR-Lipid technology. [ Methods] Egg was extracted by acidified acetonitrile, purified by Bond Elut EMR-Lipid QuEChERS, and detected by HPLC-MS/MS. [ Results] The three kinds of polyether residues had good linear relationships in the range of 2.0 - 100 μg/L with peak areas, r 〉 0. 999. The recoveries ranged from 84.6% to 107.0%. [ Conclusions ] The method is convenient and accurate, and the quantitative results are accurate and reproducible. It is suitable for the determination of the three kinds of polyether residues in eggs.
基金financially supported by National Postdoctoral Program for Innovative Talent (No. BX20200200)Youth Fund of National Natural Science Foundation of China (No. 52109126)Joint Funds of the National Natural Science Foundation of China (No. U1706223)。
文摘Recently a new grout material called water inflow sealing(WIS) was invented for sealing water inflow in tunneling and underground constructions. In this study, a special experimental method called intubated counter grouting(ICG) was proposed to investigate the influence of water dispersion on the rheological properties of the grout during the grouting process, and to testify the sealing performance of the grout,such as instant gelling ability(IGA) and anti-dispersion ability(ADA). In the experiment, dispersion was restricted in the downstream of the channel with a high turbulence intensity. The influences of ADA and IGA were therefore decoupled and evaluated separately. Experimental results revealed two distinctive sealing mechanisms of WIS. For a low initial velocity of water, WIS turned the shear flow of water into an overall movement of a plug by absorbing water into the particles. For a high initial velocity and the situation that the particles reached the outlet before sufficiently expanding, WIS modified the rheology of the water in the channel and reduced its velocity till the static state. The distinctive feature of WIS brings a reformation on the sealing mechanism and provides an effective way to control water inflow with high pressure and velocity.
基金Supported by Science and Technology Planning Project of Guangdong Province(2014A040401008)
文摘[Objectives] To establish Qu ECh ERS based extraction method for determining multiple pesticide residues in okra combined with programmed temperature vaporizer-gas chromatography-triple quadrupole mass spectrometry( PTV-GC-MS/MS) and ultra high performance liquid chromatography-mass spectrometry( UPLC-MS/MS). [Methods] In this experiment,124 pesticide residues in okra were determined by an optimized Qu ECh ERS method combined with PTV-GC-MS/MS and UPLC-MS/MS. The pesticides in okra were extracted and purified by the optimized Qu ECh ERS pretreatment method and determined by PTV-GC-MS/MS and UPLC-MS/MS. [Results] In this experiment,124 kinds of pesticides had a good linearity with a limit of detection( LOD) of 0. 000 5-0. 008 0 mg/kg; the average recovery rate at three levels was 65. 5%-128. 1% with relative standard deviation of 2. 2%-9. 7%. [Conclusions] This method is simple,rapid,accurate and sensitive,and can provide reliable and valid data support for the determination of multiple pesticide residues in okra by GC-MS/MS and UPLC-MS/MS.
基金supported by National Natural Science Foundation of China(52174386,21806132)the National Key Research and Development Program of China(2018YFC1903500)+1 种基金the Science and Technology Plan Project of Sichuan Province(2021YFH0058)the Key Research and Development Program of Guangxi Province(AB18126088)。
文摘Electrolytic manganese metal residue(EMMR)harmless treatment has always lacked a low-cost and quick processing technology.In this study,surfactants,namely tetradecyl trimethylammonium chloride(TTC),sodium dodecyl benzene sulfonate(SDBS),sodium lignin sulfonate(SLS),and octadecyl trimethylammonium chloride(OTC),were used in the solidification of Mn^(2+)and removal of NH_(4)^(+)-N from EMMR.The Mn^(2+)and NH_(4)^(+)-N concentrations under different reaction conditions,Mn^(2+)solidification and NH_(4)^(+)-N removal mechanisms,and leaching behavior were studied.The results revealed that the surfactants could enhance the Mn^(2+)solidification and NH_(4)^(+)-N removal from EMMR,and the order of enhancement was as follows:TTC>SDBS>OTC>SLS.The NH_(4)^(+)-N and Mn^(2+)concentrations were 12.3 and 0.05 mg·L^(-1)with the use of 60.0 mg·kg^(-1)TTC under optimum conditions(solid–liquid ratio of 1.5:1,EMMR to BRM mass ratio of 100:8,temperature of 20℃,and reaction duration of 12 h),which met the integrated wastewater discharge standard(GB8978-1996).Mn^(2+)was mainly solidified as Mn(OH)_(2),MnOOH and MnSiO_(3),and NH_(4)^(+)-N in EMMR was mostly removed in the form of ammonia.The results of this study could provide a new idea for cost-effective EMMR harmless treatment.
基金sponsored by the National Natural Science Foundation of China(No.22276153).The authors would like to thank the Shiyanjia Lab for the XRD test.
文摘Spent lead paste(SLP)presents a major recycling challenge in lead-acid battery treatment due to its insoluble lead compounds.This study develops an innovative and environmentally sustainable approach by integrating(NH_(4))_(2)SO_(4)-NH_(3)·H_(2)O with suspension electrolysis,effectively converting poorly soluble PbSO_(4)into soluble[Pb(NH_(3))_(4)]^(2+)complexes.The electrolytic conversion mechanisms of SLP components are systematically elucidated,revealing four distinct transformation pathways:1)metallic Pb undergoes complete dissolution as[Pb(NH_(3))_(4)]^(2+)complexes followed by cathodic reduction to elemental lead;2)PbO_(2)increases after suspension electrolysis since part of PbO is oxidized;3)PbO demonstrates dual behavior,with 45.74%undergoing anodic oxidation to PbO_(2) while the remainder(54.26%)participates in cathodic electrodeposition;4)PbSO_(4)exhibits triple conversion routes,including:1)32.98%transformation through intermediate(NH_(4))Pb(OH)SO_(4)formation followed by anodic conversion to PbO·PbSO_(4),2)21.36%direct cathodic reduction to metallic lead,and 3)the residual fraction maintaining soluble[Pb(NH_(3))_(4)]^(2+)speciation in the electrolyte.The optimized process achieves exceptional current efficiency(95.49%)and lead recovery(45.67%),with anode residues comprising 67.58%PbO_(2)and 32.42%PbO·PbSO_(4).Remarkably,this process exhibits significant economic and environmental advantages,with recycling 1 kg of SLP through the(NH_(4))_(2)SO_(4)-NH_(3)·H_(2)O suspension electrolysis process resulting in a net profit of 0.3466 USD and a reduction in carbon emissions of 119.758 kg CO_(2)eq.,offering dual advantages of environmental and economic benefits.This work provides fundamental insights into lead phase conversion during suspension electrolysis while presenting a practical,effective solution for battery recycling industries.
基金supported by a grant from the National Natural Science Foundation of China(Grant No.51974262)the Science&Technology Pillar Program of Sichuan Province(No.2019YFS0450)support from the Lincoln Dynamic Foundation’s World Institute for Sustainable Development of Materials(WISDOM).
文摘The concept of zero waste is an ideal situation that will require different solutions for different categories of waste.Electronic waste(E-waste),the fastest growing category of solid hazardous waste presents various unique challenges.Electronic product repair,reuse and remanufacture(3re)are crucial for effective source reduction of E-waste and the integration of the electronics industry into a circular or zero-waste economy framework.Increasingly,3re implementation is restricted by regulatory difficulties,particularly the invocation of copyright laws.Here,we use the examples of electronic printer cartridges and restored compact discs(CDs)to identify the challenges and to explore solutions for managing the risks associated with E-waste through circular economy and the opportunities presented by innovative Blockchain solutions.A set of international consensuses on judicial definitions,such as 3re,refurbish fake/counterfeit product and copyright exhaustion,are proposed to accelerate source reduction in E-waste management toward the goal of zero waste.
文摘Copper recovery is the core of waste printed circuit boards （WPCBs） treatment. In this study, we proposed a feasible and efficient way to recover copper from WPCBs concentrated metal scraps by direct electrolysis and thctors that affect copper recovery rate and purity, mainly CuSO4.5H2O concentration, NaCI concentration, H2SO4 concentration and current density, were discussed in detail. The results indicated that copper recovery rate increased first with the increase ofCuSO4- 5H2O, NaCI, H2SO4 and current density and then decreased with further increasing these conditions. NaCI, H2SO4 and current density also showed a similar impact on copper purity, which also increased first and then decreased. Copper purity increased with the increase of CuSO4.5H2O. When the concentration of CuSO4-5H2O NaCI and H2oSO4 was respectively 90, 40 and 118 g/L and current density was 80 mA/cm-, copper recovery rate and purity was up to 97.32% and 99.86%, respectively. Thus, electrolysis proposes a feasible and prospective approach for waste printed circuit boards recycle, even for e-waste, though more researches are needed for industrial application.
基金supported by the National Natural Science Foundation of China(No.51974262)by the Science&Technology Pillar Program of Sichuan Province(No.2019YFS0450).
文摘Superfine copper particles could be directly prepared from waste printed circuit boards by slurry electrolysis.Meanwhile,copper fractal growth could be observed.To better understand this phenomenon,the factors that affect copper dendrites in a point-cathode system were discussed in detail.These results showed that the fractal degree of copper dendrites increased as the increase of applied voltage and the decrease of copper sulfate and gelatin concentrations.Sodium lauryl sulfate and hydrochloric acid concentrations could not significantly impact the fractal degree of copper dendrites,while gelatin concentration could.The minimum copper fractal dimension was 1.069 when gelatin and copper sulfate concentration was 120 mg/L and 0.1 mol/L,respectively with an applied voltage of 11 V.Moreover,the results diffusion-limited aggregation model demonstrated that particle translational speed,particle numbers and binding probability significantly affected copper dendrite patterns.The scanning electron microscopy results indicated that the three additives greatly affected the refinement of the copper crystal.These findings contribute to enrich the theoretical study on metals recovery from e-waste by slurry electrolysis.
