In this work,porous biochar(MN-TRB_(750))was fabricated via direct pyrolysis of tea residue(TR)and Mg(NO_(3))_(2)·6H_(2)O(MN).The as-synthesized MN-TRB_(750) reached a specific surface area of 839.54 m^(2)·g...In this work,porous biochar(MN-TRB_(750))was fabricated via direct pyrolysis of tea residue(TR)and Mg(NO_(3))_(2)·6H_(2)O(MN).The as-synthesized MN-TRB_(750) reached a specific surface area of 839.54 m^(2)·g^(-1)and an average pore size of 3.75 nm with multi-level pore architecture.MN decreased TR's carbonization temperature and promoted the aromatics extent,pore structure for the frizzly flake-like biochar.Rhodamine B(RhB)was chosen as the adsorbate to explore the removal performance of organic dyes in this study.The results indicated that the maximum adsorption capacity of RhB on MN-TRB_(750) at 20℃ is up to 809.0 mg·g^(-1)with isotherms fitted well to Freundlich and Dubinin-Radushkevic models.The adsorption kinetics followed pseudo-second-order and Elovich models with an equilibrium adsorption capacity of 757.6 mg·g^(-1)as the initial concentration of RhB is 260 mg·L^(-1).High pore filling,hydrogen bond,π-πinteraction determined the adsorption of RhB onto MN-TRB850 through a multi-active center and exothermic chemical sorption process.展开更多
We investigated the effects of different barium compounds on the thaumasite form of sulphate attack（TSA）resistance of cement-based materials when they were used as admixtures in mortars.Moreover,we analyzed the inhi...We investigated the effects of different barium compounds on the thaumasite form of sulphate attack（TSA）resistance of cement-based materials when they were used as admixtures in mortars.Moreover,we analyzed the inhibition mechanisms within different types of barium salts,namely BaCO_3 and Ba（OH）_2,on the thaumasite formation.The controlcement mortar and mortars with barium salts to cement and limestone weight ratios of 0.5%,1.0%,and 1.5% were immersed in 5%（by weight）MgSO_4 solution at 5 ℃ to mimic TSA.Appearance,mass,and compressive strength of the mortar samples were monitored and measured to assess the generaldegradation extent of these samples.The products of sulphate attack were further analyzed by XRD,FTIR,and SEM,respectively.Experimentalresults show that different degradation extent is evident in allmortars cured in MgSO_4 solution.However,barium salts can greatly inhibit such degradation.Barium in hydroxide form has better effectiveness in protection against TSA than carbonate form,which may be due to their solubility difference in alkaline cement pore solution,and the presence of these barium compounds can reduce the degree of TSA by comparison with the almost completely decomposed controlsamples.展开更多
The heterojunction effect can effectively improve the separation efficiency of the photocatalyst’s photo-generated electron and hole pairs,thereby greatly improving the photocatalytic hydrogen production performance ...The heterojunction effect can effectively improve the separation efficiency of the photocatalyst’s photo-generated electron and hole pairs,thereby greatly improving the photocatalytic hydrogen production performance of the photocatalyst.In this paper,Bi_(6)O_(6)(OH)_(3)(NO_(3))_(3)·1.5H_(2)O(BBN)and ZnO are used to construct and synthesize Bi_(6)O_(6)(OH)_(3)(NO_(3))_(3)·1.5H_(2)O/ZnO(BBN/ZnO)heterojunction photocatalyst.Under UV-vis light irradiation,the BBN/ZnO composite could generate H_(2)with a rate of 28.66μmol·g^(−1)·h^(−1),which is higher than pure BBN(0.92μmol·g^(−1)·h^(−1))and ZnO(6.54μmol·h^(−1)·g^(−1))at around 31.1 and 4.4 times,respectively.Moreover,the experimental results found that the composite still exhibits excellent photocatalytic activity and maintains a high and stable activity in the 12-hour experiment with 3 cycles.The possible mechanism to enhance the photocatalytic behavior is attributed to the expanded light absorption range,reduced surface migration resistance,and inhibited recombination of photo-generated electron and hole pairs.展开更多
基金Supported by the Innovation and Entrepreneurship Plan Project of Shaanxi Province and Shaanxi Xueqian Normal University for College Students(S202314390048,2023DC048)。
文摘In this work,porous biochar(MN-TRB_(750))was fabricated via direct pyrolysis of tea residue(TR)and Mg(NO_(3))_(2)·6H_(2)O(MN).The as-synthesized MN-TRB_(750) reached a specific surface area of 839.54 m^(2)·g^(-1)and an average pore size of 3.75 nm with multi-level pore architecture.MN decreased TR's carbonization temperature and promoted the aromatics extent,pore structure for the frizzly flake-like biochar.Rhodamine B(RhB)was chosen as the adsorbate to explore the removal performance of organic dyes in this study.The results indicated that the maximum adsorption capacity of RhB on MN-TRB_(750) at 20℃ is up to 809.0 mg·g^(-1)with isotherms fitted well to Freundlich and Dubinin-Radushkevic models.The adsorption kinetics followed pseudo-second-order and Elovich models with an equilibrium adsorption capacity of 757.6 mg·g^(-1)as the initial concentration of RhB is 260 mg·L^(-1).High pore filling,hydrogen bond,π-πinteraction determined the adsorption of RhB onto MN-TRB850 through a multi-active center and exothermic chemical sorption process.
基金Funded by the National Natural Science Foundation of China(No.51372076)the Project of Science&Technology Department of Hubei Province(No.2014BCB027)
文摘We investigated the effects of different barium compounds on the thaumasite form of sulphate attack（TSA）resistance of cement-based materials when they were used as admixtures in mortars.Moreover,we analyzed the inhibition mechanisms within different types of barium salts,namely BaCO_3 and Ba（OH）_2,on the thaumasite formation.The controlcement mortar and mortars with barium salts to cement and limestone weight ratios of 0.5%,1.0%,and 1.5% were immersed in 5%（by weight）MgSO_4 solution at 5 ℃ to mimic TSA.Appearance,mass,and compressive strength of the mortar samples were monitored and measured to assess the generaldegradation extent of these samples.The products of sulphate attack were further analyzed by XRD,FTIR,and SEM,respectively.Experimentalresults show that different degradation extent is evident in allmortars cured in MgSO_4 solution.However,barium salts can greatly inhibit such degradation.Barium in hydroxide form has better effectiveness in protection against TSA than carbonate form,which may be due to their solubility difference in alkaline cement pore solution,and the presence of these barium compounds can reduce the degree of TSA by comparison with the almost completely decomposed controlsamples.
基金This work was supported by the Natural Science Foundation of Fujian Province[2020J01833]the Fujian Engineering Research Center of New Chinese lacquer Material[No.323030030702]+3 种基金the humbly acknowledge international funding provided by Fujian Agriculture and Forestry University[No.KXB16001A]the Education Research Program for Young and Middle-aged Teachers of Fujian Education Department[No.JAT190132]the open fund of the Key Laboratory of National Forestry&Grassland Bureau for Plant Fiber Functional Materials,Fujian Agriculture and Forestry University[No.2019KFJJ15]Key Laboratory of New Functional Textile Fiber and Material of Fujian Province will open fund project in 2020[MJUKF-FMSM202005,FKLTF 1708].
文摘The heterojunction effect can effectively improve the separation efficiency of the photocatalyst’s photo-generated electron and hole pairs,thereby greatly improving the photocatalytic hydrogen production performance of the photocatalyst.In this paper,Bi_(6)O_(6)(OH)_(3)(NO_(3))_(3)·1.5H_(2)O(BBN)and ZnO are used to construct and synthesize Bi_(6)O_(6)(OH)_(3)(NO_(3))_(3)·1.5H_(2)O/ZnO(BBN/ZnO)heterojunction photocatalyst.Under UV-vis light irradiation,the BBN/ZnO composite could generate H_(2)with a rate of 28.66μmol·g^(−1)·h^(−1),which is higher than pure BBN(0.92μmol·g^(−1)·h^(−1))and ZnO(6.54μmol·h^(−1)·g^(−1))at around 31.1 and 4.4 times,respectively.Moreover,the experimental results found that the composite still exhibits excellent photocatalytic activity and maintains a high and stable activity in the 12-hour experiment with 3 cycles.The possible mechanism to enhance the photocatalytic behavior is attributed to the expanded light absorption range,reduced surface migration resistance,and inhibited recombination of photo-generated electron and hole pairs.
