Cadmium(Cd) contamination in soils is a global ecological threat. Conventional powdered biochar added to soil can temporarily immobilize Cd but is difficult to separate from soil, leading to secondary release of Cd an...Cadmium(Cd) contamination in soils is a global ecological threat. Conventional powdered biochar added to soil can temporarily immobilize Cd but is difficult to separate from soil, leading to secondary release of Cd and posing potential ecological and human health risks. The blocky biochar is also difficult to separate from the soil due to its fragile nature. One of the keys to overcome the difficulties in separating biochar from soil is to improve its mechanical strength. Blocky zeolite-biochar composites(ZBC) that have good mechanical strength were obtained after pyrolyzing the mixture of 50% feedstock and 50% zeolite powder at 400 ℃. ZBC and NaOH-activated ZBC(ZBC_a) were applied to remove Cd from soil. After sieving Cd-loaded ZBC and ZBC_a from soil, the bioavailable Cd content in the soil decreased by 59.70% and 68.54%,respectively. Zeolite contributed to improving both adsorption performance and mechanical properties of the composites. After repeating the process of “remediation-sieving-desorption-regeneration” three times, the recoveries of ZBC and ZBC_a were above 97.00%, and regeneration rates were 48.70-83.26%,respectively. Under simulated mechanical sieving conditions, ZBC and ZBC_a lost only 4.06% and 5.40%of their mass and retained their integrity. Remediation of Cd-contaminated soil with blocky zeolitebiochar composite is sustainable and safe because the removal of bioavailable Cd from soil is permanent rather than a temporary decrease of bioavailability. This study provides a reference for the preparation of separable and recyclable adsorbents for the removal of contaminants from soil.展开更多
Due to strong synergistic effect of the elements,a series of XEuMnO_(x) ternary oxides(X=Ce,Ni,Co,Sb,Sn,Mo) were synthesized by one-pot co-precipitation method,and composite components were identified and optimized to...Due to strong synergistic effect of the elements,a series of XEuMnO_(x) ternary oxides(X=Ce,Ni,Co,Sb,Sn,Mo) were synthesized by one-pot co-precipitation method,and composite components were identified and optimized to maintain high activity and superior SO_(2)and H_(2)O endurance in selective catalytic reduction of NO_(x)with NH_(3)(NH_(3)-SCR).NO_(x)conversion of CeEuMnO_(x) ternary oxide catalysts attains more than 90% at 100-250℃,and finally achieves 74%under existence of 50×10^(-6)SO_(2) and 10 vol% H_(2)O at 230℃.The facile electron transfer through redox cycle of Mn^(3+)+Ce^(4+)■Mn4++Ce^(3+) and enhanced oxygen mobility can promote formation of more Mn species in high oxidation state and chemisorbed oxygen,accelerating oxidation of NO and the adsorbed NO_(2) formed can facilitate"fast SCR"reaction to improve low-temperature activity.In situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)study reveals that addition of Ce to EuMnO_(x)catalyst boosts adsorption of NH_(3)and NO_(x)species.NH_(3)species are activated as crucial intermediate(NH_(2))to promote NH_(3)-SCR reaction.This research provides a novel material for practical deNO_(x)application of stationary source combustion flue gas in the future.展开更多
Volatile organic compounds(VOCs)with high toxicity and carcinogenicity are emitted from kinds of industries,which endanger human health and the environment.Adsorption is a promising method for the treatment of VOCs du...Volatile organic compounds(VOCs)with high toxicity and carcinogenicity are emitted from kinds of industries,which endanger human health and the environment.Adsorption is a promising method for the treatment of VOCs due to its low cost and high efficiency.In recent years,activated carbons,zeolites,and mesoporous materials are widely used to remove VOCs because of their high specific surface area and abundant porosity.However,the hydrophilic nature and low desorption rate of those materials limit their commercial application.Furthermore,the adsorption capacities of VOCs still need to be improved.Porous organic polymers(POPs)with extremely high porosity,structural diversity,and hydrophobic have been considered as one of the most promising candidates for VOCs adsorption.This review generalized the superiority of POPs for VOCs adsorption compared to other porous materials and summarized the studies of VOCs adsorption on different types of POPs.Moreover,the mechanism of competitive adsorption between water and VOCs on the POPs was discussed.Finally,a concise outlook for utilizing POPs for VOCs adsorption was discussed,noting areas in which further work is needed to develop the next-generation POPs for practical applications.展开更多
Research on particulate characteristics has been an important frontier in physics and chemistry during the past decades. It has however been mostly focused on granular materials with short-range interactions. In this ...Research on particulate characteristics has been an important frontier in physics and chemistry during the past decades. It has however been mostly focused on granular materials with short-range interactions. In this work, it was found that the power law of particle size distribution applied to the long-range interacting system of floating dust in air, from which we deduced that self-organized criticality might hold for floating dust just as granular materials with short-range interactions. This feature may reveal underlying kinetic mechanisms, important in dispersed particle systems. In industry, power law of size distribution of dispersed particles can be used to investigate the change of dust size, and the power law parameter could be taken as an important index for dust separation.展开更多
基金supported by the National Key Research and Development Program of China, China (2019YFC1904102)。
文摘Cadmium(Cd) contamination in soils is a global ecological threat. Conventional powdered biochar added to soil can temporarily immobilize Cd but is difficult to separate from soil, leading to secondary release of Cd and posing potential ecological and human health risks. The blocky biochar is also difficult to separate from the soil due to its fragile nature. One of the keys to overcome the difficulties in separating biochar from soil is to improve its mechanical strength. Blocky zeolite-biochar composites(ZBC) that have good mechanical strength were obtained after pyrolyzing the mixture of 50% feedstock and 50% zeolite powder at 400 ℃. ZBC and NaOH-activated ZBC(ZBC_a) were applied to remove Cd from soil. After sieving Cd-loaded ZBC and ZBC_a from soil, the bioavailable Cd content in the soil decreased by 59.70% and 68.54%,respectively. Zeolite contributed to improving both adsorption performance and mechanical properties of the composites. After repeating the process of “remediation-sieving-desorption-regeneration” three times, the recoveries of ZBC and ZBC_a were above 97.00%, and regeneration rates were 48.70-83.26%,respectively. Under simulated mechanical sieving conditions, ZBC and ZBC_a lost only 4.06% and 5.40%of their mass and retained their integrity. Remediation of Cd-contaminated soil with blocky zeolitebiochar composite is sustainable and safe because the removal of bioavailable Cd from soil is permanent rather than a temporary decrease of bioavailability. This study provides a reference for the preparation of separable and recyclable adsorbents for the removal of contaminants from soil.
基金Project supported by the National Key R&D Program of China(2019YFC1904100,2019YFC1904102,2019YFC1903900,2019YFC1903902)the National Natural Science Foundation of China(U20A20132,52106180,22076136)+1 种基金the Hebei Province Major Scientific and Technological Achievement Transformation Fund Support Project(2021004012 A)the Central Government Guides the Local Science and Technology Development Fund Project(206Z3702G).
文摘Due to strong synergistic effect of the elements,a series of XEuMnO_(x) ternary oxides(X=Ce,Ni,Co,Sb,Sn,Mo) were synthesized by one-pot co-precipitation method,and composite components were identified and optimized to maintain high activity and superior SO_(2)and H_(2)O endurance in selective catalytic reduction of NO_(x)with NH_(3)(NH_(3)-SCR).NO_(x)conversion of CeEuMnO_(x) ternary oxide catalysts attains more than 90% at 100-250℃,and finally achieves 74%under existence of 50×10^(-6)SO_(2) and 10 vol% H_(2)O at 230℃.The facile electron transfer through redox cycle of Mn^(3+)+Ce^(4+)■Mn4++Ce^(3+) and enhanced oxygen mobility can promote formation of more Mn species in high oxidation state and chemisorbed oxygen,accelerating oxidation of NO and the adsorbed NO_(2) formed can facilitate"fast SCR"reaction to improve low-temperature activity.In situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)study reveals that addition of Ce to EuMnO_(x)catalyst boosts adsorption of NH_(3)and NO_(x)species.NH_(3)species are activated as crucial intermediate(NH_(2))to promote NH_(3)-SCR reaction.This research provides a novel material for practical deNO_(x)application of stationary source combustion flue gas in the future.
基金supported by the National Key R&D Pro-gram of China(Nos.2019YFC1904100,2019YFC1904102,2019YFC1903902,and 2016YFC0205300)the National En-gineering Laboratory for Mobile Source Emission Control Technology of China(No.NELMS2017A03)+3 种基金the Natural Na-tional Science Foundation of China(Nos.21503144,21690083)Tianjin Research Program of Ecological Environmental Treat-ment(Nos.18ZXSZSF00210,18ZXSZSF00060)the Tianjin Research Program of Application Foundation and Advanced Technique(No.16JCQNJC05400)Major Science and Tech-nology Project for Ecological Environment Management in Tianjin(No.18ZXSZSF00210)。
文摘Volatile organic compounds(VOCs)with high toxicity and carcinogenicity are emitted from kinds of industries,which endanger human health and the environment.Adsorption is a promising method for the treatment of VOCs due to its low cost and high efficiency.In recent years,activated carbons,zeolites,and mesoporous materials are widely used to remove VOCs because of their high specific surface area and abundant porosity.However,the hydrophilic nature and low desorption rate of those materials limit their commercial application.Furthermore,the adsorption capacities of VOCs still need to be improved.Porous organic polymers(POPs)with extremely high porosity,structural diversity,and hydrophobic have been considered as one of the most promising candidates for VOCs adsorption.This review generalized the superiority of POPs for VOCs adsorption compared to other porous materials and summarized the studies of VOCs adsorption on different types of POPs.Moreover,the mechanism of competitive adsorption between water and VOCs on the POPs was discussed.Finally,a concise outlook for utilizing POPs for VOCs adsorption was discussed,noting areas in which further work is needed to develop the next-generation POPs for practical applications.
基金The present project is currently sponsored by the National Natural Science Foundation of China through Contract#50406018the Scientific Research Foundation for Returned Overseas Chinese Scholars.
文摘Research on particulate characteristics has been an important frontier in physics and chemistry during the past decades. It has however been mostly focused on granular materials with short-range interactions. In this work, it was found that the power law of particle size distribution applied to the long-range interacting system of floating dust in air, from which we deduced that self-organized criticality might hold for floating dust just as granular materials with short-range interactions. This feature may reveal underlying kinetic mechanisms, important in dispersed particle systems. In industry, power law of size distribution of dispersed particles can be used to investigate the change of dust size, and the power law parameter could be taken as an important index for dust separation.