In this study,we investigated the performance of a synthetic resin for the adsorption of Li from predesilicated solution which is the waste liquid produced by extracting aluminum from fly ash.The adsorption kinetics a...In this study,we investigated the performance of a synthetic resin for the adsorption of Li from predesilicated solution which is the waste liquid produced by extracting aluminum from fly ash.The adsorption kinetics and isotherms of the resin were obtained and analyzed.The saturated adsorption sites of the resin were in agreement with the quasi-second-order kinetic model.Then,the pore diffusion model(PDM)was applied to represent the lithium adsorption kinetics which confirming that the external mass is the limiting step.Moreover,we evaluated the adsorption properties of this resin in fixed-bed mode.We established a feasible extraction process for Li from strong alkaline solutions with low Li concentrations.The process parameters,such as the flow rate,initial adsorption solution concentration,water washing process,desorption agent concentration,and flow rate were studied.The desorption rate of the Li;ions was directly proportional with the concentration of the desorption agent.The time required to accumulate Li decreased as the hydrochloric acid concentration and flow rate increased.Time of the peak appeared increased from 0.5 bed volume(BV)to 2.5 BV as the concentration was increased from 1 to3 mol·L^(-1),and the peak increased from 231 to 394 mg·L^(-1).The resin presented good selectivity for Li;ions and could effectively separate impurity ions from the pre-desilication solution.展开更多
A combined acid–alkali hydrothermal method was used to prepare fly ash–derived SAPO-34 molecular sieves from a thermal power plant in Inner Mongolia(China).The specific surface area of the prepared fly-ash-derived S...A combined acid–alkali hydrothermal method was used to prepare fly ash–derived SAPO-34 molecular sieves from a thermal power plant in Inner Mongolia(China).The specific surface area of the prepared fly-ash-derived SAPO-34 molecular sieves was 579 m^2 g^-1,the total pore volume was about 0.27 cm^3 g^-1,and the pore size was 0.56 nm;the molar ratios of Al2O3:P2O5:SiO2 were 1:0.86:0.45.Cu/SAPO-34 catalysts were prepared by impregnation of low-cost fly-ash-derived SAPO-34 molecular sieves as a support and tested in selective catalytic reduction with NH3(NH3-SCR).Powder X-ray diffraction(XRD),N2 adsorption–desorption,X-ray photoelectron spectroscopy(XPS),H2 temperatureprogrammed reduction(H2-TPR),NH3 temperature-programmed desorption(NH3-TPD),electron paramagnetic resonance(EPR),nuclear magnetic resonance(NMR),X-ray fluorescence analysis(XRF)and scanning electron microscopy(SEM)were used for catalyst characterization and investigation of the relationships between the catalyst structure and the catalytic activity.The actual silica:alumina ratio of the molecular sieves did not increase with increasing Cu loading,indicating that increasing the Cu loading does not change the original structure of the SAPO-34 molecular sieves.The XRF and NMR results showed that replacement by Cu results in more Si islands.The molecular sieve acidity decreased because of the increased number of Si islands.The NH3-TPD results showed that for the Cu/SAPO-34 catalysts there was a low correlation between the low-temperature activity and the amount of acidic sites.SCR activity is closely related to the location of Cu.The 4.47 Cu/SAPO-34 catalyst has the highest isolated Cu2+showed the highest NH3-SCR activities(>90%)at 250–350℃.This work opens up new avenues for recycling fly ash formed in coal-fired power plants(reducing environmental pollution)and developing low-cost SCR catalysts for NOx pollution control.展开更多
A thermal insulating material is synthesized via a non-steam-cured and non-fired route by using fly-ash, sorel cement and hydrogen peroxide solution as raw material. Properties such as apparent density, compressive st...A thermal insulating material is synthesized via a non-steam-cured and non-fired route by using fly-ash, sorel cement and hydrogen peroxide solution as raw material. Properties such as apparent density, compressive strength, bending strength, thermal conductivity, water resistance, and thermal tolerance of this matrial are studied, some influencing factors on its performance discussed. This material has an apparent density of 360 kg/m^3, a compressive strength of 1.86 MPa, a thermal conduction coefficient of 0.072 W/（m·K）, a softening coefficient of 0.55, and a thermal tolerant temperature of 300 ℃. Test results show that this material is light in weight, of high strength, and good thermal insulation. In addition, neither steam-curing nor sintering is needed in producing it. Further more, large amount of fly ash is used in this material, making it a low cost and environment-friendly building material.展开更多
1-{4-[（2-hydroxy-benzylidene）amino]phenyl}ethanone functionalized silica gel was synthesized and used as a highly efficient, selective and reusable solid phase extractant for separation and preconcentration of trace...1-{4-[（2-hydroxy-benzylidene）amino]phenyl}ethanone functionalized silica gel was synthesized and used as a highly efficient, selective and reusable solid phase extractant for separation and preconcentration of trace amount of Zn（II） from environmental matrices. The adsorbent was characterized by fourier transform infrared spectroscopy （FT-IR）, elemental analysis,~3C CPMAS NMR spectroscopy, scanning electron microscopy （SEM）, thermogravimetric analysis （TGA） and BET surface area analysis. The dependence of zinc extraction on various analytical parameters such as pH, type and amount of eluent, sample flow rate and interfering ions were investigated in detail. The material exhibited superior adsorption efficiency for Zn（II） with high metal loading capacity of 1.0 mmol/g under optimum conditions. After adsorption, the recovery （〉 98%） of metal ions was accomplished using 1.0 mol/L HNO3 as an eluent. The sorbent was also regenerated by microwave treatment in milder acidic environment （0.1 mol/L HNO3）. The lower detection limit and preconcentration factor of the present method were found out to be 0.04 ~tg/L and 312.5 respectively. The modified silica surface possessed excellent selectivity for the target analytes and the adsorption/desorption process remained effective for at least ten consecutive cycles. The optimized procedure was successfully implemented for the extraction of Zn（II） from mycorrhizal treated fly ash and pharmaceutical samples with reproducible results.展开更多
Copper particles emitted from braking have become a significant source of environmental pollution.However,copper plays a crucial role in resin-based braking materials.Developing high-performance braking materials with...Copper particles emitted from braking have become a significant source of environmental pollution.However,copper plays a crucial role in resin-based braking materials.Developing high-performance braking materials without copper has become a significant challenge.In this paper,the resin-based braking materials were filled with flyash cenospheres to develop copper-free braking materials.The effects of fly-ash cenospheres on the physical properties,mechanical and friction and wear properties of braking materials were studied.Furthermore,the wear mechanism of copper-free resin-based braking materials filled with fly-ash cenospheres was discussed.The results indicate that the inclusion of fly-ash cenospheres in the braking materials improved their thermal stability,hardness and impact strength,reduced their density,effectively increased the friction coefficient at medium and high temperatures,and enhanced the heat-fade resistance of the braking materials.The inclusion of fly-ash cenospheres contributed to the formation of surface friction film during the friction process of the braking materials,and facilitated the transition of form from abrasive wear to adhesive wear.At 100-350℃,the friction coefficient of the optimal formulation is in the range of 0.57-0.61,and the wear rate is in the range(0.29-0.65)×10^(-7) cm^(3)·N^(-1)·m^(-1),demonstrating excellent resistance to heat-fade and stability in friction coefficient.This research proposes the use of fly-ash cenospheres as a substitute for environmentally harmful and expensive copper in brake materials,which not only improves the performance of braking materials but also reduces their costs.展开更多
In this paper, the fly-ash ceramics with prior physical propertieswas fabricated in a low sintering temperature range. XRD, SEM wereused to study the microstructure and sintering mechanism. The resultsshow that in thi...In this paper, the fly-ash ceramics with prior physical propertieswas fabricated in a low sintering temperature range. XRD, SEM wereused to study the microstructure and sintering mechanism. The resultsshow that in this fly-ash ceramics, three kinds of matter form itsstructure frame such as the glass pearls from the fly-ash rawmaterials, quartz and mullite in which glass liquid phase wasproduced during sintering. And the sintering mechanism is that ofliquid sintering.展开更多
With the rising of IGCC and the second generation PFBC-CC, and with the development of tech-nology of staged combustion to lower emission of NOx, the desulfurization efficiency under reducingatmosphere is raised. In t...With the rising of IGCC and the second generation PFBC-CC, and with the development of tech-nology of staged combustion to lower emission of NOx, the desulfurization efficiency under reducingatmosphere is raised. In this paper, with the application of the fly-ash recycle and tworstage combus-tion technologies in a fluidized bed combustor, the desulfurization test under reducing atmosphere isdescribed. Meanwllile, ammonia injection test was also conducted. Results show that desulfurizationunder reducing atmosphere has higher efficiency, and ammonia injection denitrification effect is veryperfect.展开更多
Geopolymer, an inorganic aluminosilicate material activated by alkaline medium solution, can perform as an inorganic adhesive. The geopolymer technology has a viability to substitute traditional concrete made of portl...Geopolymer, an inorganic aluminosilicate material activated by alkaline medium solution, can perform as an inorganic adhesive. The geopolymer technology has a viability to substitute traditional concrete made of portland cement （PC） because replacing PC with fly ash leads to reduced carbon dioxide emissions from cement productions and reduced materials cost. Although fly ash geopolymer stimulates sustainability, it is slow geopolymerization reaction poses a challenge for construction technology in term of practicality. The development of increasing geopolymerization reaction rate of the geopolymer is needed. The purpose of this study is to evaluate seeding nucleation agents （NA） of fly ash geopolymer that can accelerate polymerization reactions such that the geopolymer can be widely used in the construction industry. Results from the present study indicate that the use of NA （i.e., Ca（OH）2） can be potentially used to increase geopolymerization reaction rate and improve performance characteristics of the fly ash geopolymer product.展开更多
粉煤灰长期堆存会释放大量有毒有害物质,并对水环境构成威胁。为全面了解该领域的研究进展,采用文献计量学方法,系统并深入地对CNKI和Web of Science数据库中从建库至2023年间的相关文献进行了可视化分析。结果表明:该领域的年总发文量...粉煤灰长期堆存会释放大量有毒有害物质,并对水环境构成威胁。为全面了解该领域的研究进展,采用文献计量学方法,系统并深入地对CNKI和Web of Science数据库中从建库至2023年间的相关文献进行了可视化分析。结果表明:该领域的年总发文量整体呈上升趋势,其中:中国科学家在该领域进行了大量研究工作,发文量最多,占总发文量的18.87%,为后续研究提供了重要科学依据,美国发文的中介中心性(0.51)明显高于其他国家,研究成果更具国际影响力;研究热点主要围绕粉煤灰中重金属等污染物,探究其在不同条件下的浸出、淋溶释放规律,揭示粉煤灰堆场污染物迁移带来的环境影响。基于高频关键词分析,探讨了粉煤灰污染物组成特征和可能释放到水环境中的污染物类型,系统梳理和分析了污染物的释放机制、规律和关键影响因素,以及污染物在环境介质中的迁移规律研究进展。未来研究应进一步关注粉煤灰堆存过程中Pb、Cr、Hg等重金属,As、Se、Mo等微量元素和F^(-)、Cl^(-)、SO_(4)^(2-)、PO_(4)^(3-)等特征污染物的释放问题,探究复杂环境影响下特征污染物的释放特性,并明确不同因素是否存在协同或抑制机制,建立粉煤灰固相中污染物指标与其释放进入水环境的指标间的定量关系,为科学评价粉煤灰环境影响提供理论基础,进而有效防范粉煤灰中污染物对水环境的潜在威胁。展开更多
基金supported by National Key Research and Development Program of China(2017YFB0603104)Sponsored by Shanghai Pujiang Program(2019PJD011)the financial support from the State Key Laboratory of Green Chemistry Synthesis Technology(Zhejiang University of Technology,Hangzhou 310032)。
文摘In this study,we investigated the performance of a synthetic resin for the adsorption of Li from predesilicated solution which is the waste liquid produced by extracting aluminum from fly ash.The adsorption kinetics and isotherms of the resin were obtained and analyzed.The saturated adsorption sites of the resin were in agreement with the quasi-second-order kinetic model.Then,the pore diffusion model(PDM)was applied to represent the lithium adsorption kinetics which confirming that the external mass is the limiting step.Moreover,we evaluated the adsorption properties of this resin in fixed-bed mode.We established a feasible extraction process for Li from strong alkaline solutions with low Li concentrations.The process parameters,such as the flow rate,initial adsorption solution concentration,water washing process,desorption agent concentration,and flow rate were studied.The desorption rate of the Li;ions was directly proportional with the concentration of the desorption agent.The time required to accumulate Li decreased as the hydrochloric acid concentration and flow rate increased.Time of the peak appeared increased from 0.5 bed volume(BV)to 2.5 BV as the concentration was increased from 1 to3 mol·L^(-1),and the peak increased from 231 to 394 mg·L^(-1).The resin presented good selectivity for Li;ions and could effectively separate impurity ions from the pre-desilication solution.
基金support by the National High Technology Research and Development Program (“863” program) of China (2012AA06A115)China Postdoctoral Science Foundation (2017M610723)
文摘A combined acid–alkali hydrothermal method was used to prepare fly ash–derived SAPO-34 molecular sieves from a thermal power plant in Inner Mongolia(China).The specific surface area of the prepared fly-ash-derived SAPO-34 molecular sieves was 579 m^2 g^-1,the total pore volume was about 0.27 cm^3 g^-1,and the pore size was 0.56 nm;the molar ratios of Al2O3:P2O5:SiO2 were 1:0.86:0.45.Cu/SAPO-34 catalysts were prepared by impregnation of low-cost fly-ash-derived SAPO-34 molecular sieves as a support and tested in selective catalytic reduction with NH3(NH3-SCR).Powder X-ray diffraction(XRD),N2 adsorption–desorption,X-ray photoelectron spectroscopy(XPS),H2 temperatureprogrammed reduction(H2-TPR),NH3 temperature-programmed desorption(NH3-TPD),electron paramagnetic resonance(EPR),nuclear magnetic resonance(NMR),X-ray fluorescence analysis(XRF)and scanning electron microscopy(SEM)were used for catalyst characterization and investigation of the relationships between the catalyst structure and the catalytic activity.The actual silica:alumina ratio of the molecular sieves did not increase with increasing Cu loading,indicating that increasing the Cu loading does not change the original structure of the SAPO-34 molecular sieves.The XRF and NMR results showed that replacement by Cu results in more Si islands.The molecular sieve acidity decreased because of the increased number of Si islands.The NH3-TPD results showed that for the Cu/SAPO-34 catalysts there was a low correlation between the low-temperature activity and the amount of acidic sites.SCR activity is closely related to the location of Cu.The 4.47 Cu/SAPO-34 catalyst has the highest isolated Cu2+showed the highest NH3-SCR activities(>90%)at 250–350℃.This work opens up new avenues for recycling fly ash formed in coal-fired power plants(reducing environmental pollution)and developing low-cost SCR catalysts for NOx pollution control.
基金Project 20062147 supported by the Liaoning Province Natural Science Foundation of China
文摘A thermal insulating material is synthesized via a non-steam-cured and non-fired route by using fly-ash, sorel cement and hydrogen peroxide solution as raw material. Properties such as apparent density, compressive strength, bending strength, thermal conductivity, water resistance, and thermal tolerance of this matrial are studied, some influencing factors on its performance discussed. This material has an apparent density of 360 kg/m^3, a compressive strength of 1.86 MPa, a thermal conduction coefficient of 0.072 W/（m·K）, a softening coefficient of 0.55, and a thermal tolerant temperature of 300 ℃. Test results show that this material is light in weight, of high strength, and good thermal insulation. In addition, neither steam-curing nor sintering is needed in producing it. Further more, large amount of fly ash is used in this material, making it a low cost and environment-friendly building material.
文摘1-{4-[（2-hydroxy-benzylidene）amino]phenyl}ethanone functionalized silica gel was synthesized and used as a highly efficient, selective and reusable solid phase extractant for separation and preconcentration of trace amount of Zn（II） from environmental matrices. The adsorbent was characterized by fourier transform infrared spectroscopy （FT-IR）, elemental analysis,~3C CPMAS NMR spectroscopy, scanning electron microscopy （SEM）, thermogravimetric analysis （TGA） and BET surface area analysis. The dependence of zinc extraction on various analytical parameters such as pH, type and amount of eluent, sample flow rate and interfering ions were investigated in detail. The material exhibited superior adsorption efficiency for Zn（II） with high metal loading capacity of 1.0 mmol/g under optimum conditions. After adsorption, the recovery （〉 98%） of metal ions was accomplished using 1.0 mol/L HNO3 as an eluent. The sorbent was also regenerated by microwave treatment in milder acidic environment （0.1 mol/L HNO3）. The lower detection limit and preconcentration factor of the present method were found out to be 0.04 ~tg/L and 312.5 respectively. The modified silica surface possessed excellent selectivity for the target analytes and the adsorption/desorption process remained effective for at least ten consecutive cycles. The optimized procedure was successfully implemented for the extraction of Zn（II） from mycorrhizal treated fly ash and pharmaceutical samples with reproducible results.
基金Supported by National Natural Science Foundation of China(Grant No.52275178)Fujian Provincial Natural Science Foundation of China(Grant Nos.2020J05115,2022J01073)Project National United Engineering Laboratory for Advanced Bearing Tribology,Henan University of Science and Technology of China(Grant No.202103).
文摘Copper particles emitted from braking have become a significant source of environmental pollution.However,copper plays a crucial role in resin-based braking materials.Developing high-performance braking materials without copper has become a significant challenge.In this paper,the resin-based braking materials were filled with flyash cenospheres to develop copper-free braking materials.The effects of fly-ash cenospheres on the physical properties,mechanical and friction and wear properties of braking materials were studied.Furthermore,the wear mechanism of copper-free resin-based braking materials filled with fly-ash cenospheres was discussed.The results indicate that the inclusion of fly-ash cenospheres in the braking materials improved their thermal stability,hardness and impact strength,reduced their density,effectively increased the friction coefficient at medium and high temperatures,and enhanced the heat-fade resistance of the braking materials.The inclusion of fly-ash cenospheres contributed to the formation of surface friction film during the friction process of the braking materials,and facilitated the transition of form from abrasive wear to adhesive wear.At 100-350℃,the friction coefficient of the optimal formulation is in the range of 0.57-0.61,and the wear rate is in the range(0.29-0.65)×10^(-7) cm^(3)·N^(-1)·m^(-1),demonstrating excellent resistance to heat-fade and stability in friction coefficient.This research proposes the use of fly-ash cenospheres as a substitute for environmentally harmful and expensive copper in brake materials,which not only improves the performance of braking materials but also reduces their costs.
文摘In this paper, the fly-ash ceramics with prior physical propertieswas fabricated in a low sintering temperature range. XRD, SEM wereused to study the microstructure and sintering mechanism. The resultsshow that in this fly-ash ceramics, three kinds of matter form itsstructure frame such as the glass pearls from the fly-ash rawmaterials, quartz and mullite in which glass liquid phase wasproduced during sintering. And the sintering mechanism is that ofliquid sintering.
文摘With the rising of IGCC and the second generation PFBC-CC, and with the development of tech-nology of staged combustion to lower emission of NOx, the desulfurization efficiency under reducingatmosphere is raised. In this paper, with the application of the fly-ash recycle and tworstage combus-tion technologies in a fluidized bed combustor, the desulfurization test under reducing atmosphere isdescribed. Meanwllile, ammonia injection test was also conducted. Results show that desulfurizationunder reducing atmosphere has higher efficiency, and ammonia injection denitrification effect is veryperfect.
文摘Geopolymer, an inorganic aluminosilicate material activated by alkaline medium solution, can perform as an inorganic adhesive. The geopolymer technology has a viability to substitute traditional concrete made of portland cement （PC） because replacing PC with fly ash leads to reduced carbon dioxide emissions from cement productions and reduced materials cost. Although fly ash geopolymer stimulates sustainability, it is slow geopolymerization reaction poses a challenge for construction technology in term of practicality. The development of increasing geopolymerization reaction rate of the geopolymer is needed. The purpose of this study is to evaluate seeding nucleation agents （NA） of fly ash geopolymer that can accelerate polymerization reactions such that the geopolymer can be widely used in the construction industry. Results from the present study indicate that the use of NA （i.e., Ca（OH）2） can be potentially used to increase geopolymerization reaction rate and improve performance characteristics of the fly ash geopolymer product.
文摘粉煤灰长期堆存会释放大量有毒有害物质,并对水环境构成威胁。为全面了解该领域的研究进展,采用文献计量学方法,系统并深入地对CNKI和Web of Science数据库中从建库至2023年间的相关文献进行了可视化分析。结果表明:该领域的年总发文量整体呈上升趋势,其中:中国科学家在该领域进行了大量研究工作,发文量最多,占总发文量的18.87%,为后续研究提供了重要科学依据,美国发文的中介中心性(0.51)明显高于其他国家,研究成果更具国际影响力;研究热点主要围绕粉煤灰中重金属等污染物,探究其在不同条件下的浸出、淋溶释放规律,揭示粉煤灰堆场污染物迁移带来的环境影响。基于高频关键词分析,探讨了粉煤灰污染物组成特征和可能释放到水环境中的污染物类型,系统梳理和分析了污染物的释放机制、规律和关键影响因素,以及污染物在环境介质中的迁移规律研究进展。未来研究应进一步关注粉煤灰堆存过程中Pb、Cr、Hg等重金属,As、Se、Mo等微量元素和F^(-)、Cl^(-)、SO_(4)^(2-)、PO_(4)^(3-)等特征污染物的释放问题,探究复杂环境影响下特征污染物的释放特性,并明确不同因素是否存在协同或抑制机制,建立粉煤灰固相中污染物指标与其释放进入水环境的指标间的定量关系,为科学评价粉煤灰环境影响提供理论基础,进而有效防范粉煤灰中污染物对水环境的潜在威胁。
