As a two dimensional(2D)visible‐light‐responsive semiconductor photocatalyst,the photoreactivity of Bi2WO6 is not high enough for practical application owing to its limited response to visible light and rapid recomb...As a two dimensional(2D)visible‐light‐responsive semiconductor photocatalyst,the photoreactivity of Bi2WO6 is not high enough for practical application owing to its limited response to visible light and rapid recombination of photogenerated electron‐hole pairs.In this paper,2D core‐shell structured Bi2WO6@Bi2S3 nanoplates were prepared by calcination of a mixture of Bi2WO6(1.3 g)and a certain amount of Na2S·9H2O(0–3.0 g)at 350°C for 2 h.The reactivity of the resulting photocatalyst materials was evaluated by photocatalytic degradation of Brilliant Red X‐3B(X3B),an anionic dye,under visible light irradiation(?>420 nm).As the amount of Na2S·9H2O was increased from 0 to 1.5 g,the degradation rate constant of X3B sharply increased from 0.40×10?3 to 6.6×10?3 min?1.The enhanced photocatalytic activity of Bi2WO6@Bi2S3 was attributed to the photosensitization of Bi2S3,which greatly extended the light‐responsive range from the visible to the NIR,and the formation of a heterojunction,which retarded the recombination rate of photogenerated electron‐hole pairs.However,further increases in the amount of Na2S·9H2O(from 1.5 to 3.0 g)resulted in a decrease of the photocatalytic activity of the Bi2WO6@Bi2S3 nanoplates owing to the formation of a photo‐inactive NaBiS2 layer covering the Bi2WO6 surface.展开更多
In this study, the modified rice bran was tested to remove Pb(II) from water. Batch experiments were carried out to evaluate the adsorption characteristics of the modified rice bran for Pb(II) removal from aqueous sol...In this study, the modified rice bran was tested to remove Pb(II) from water. Batch experiments were carried out to evaluate the adsorption characteristics of the modified rice bran for Pb(II) removal from aqueous solutions. The adsorption isotherms, thermodynamic parameters, kinetics, pH effect, and desorbability were examined. The results show that the maximum adsorption capacity of the modified rice bran was approximately 70.8 mg Pb(II)/g absorbent at temperature of 25℃ and at the initial Pb(II) concentration of 400 mg/L and pH 7.0. And the adsorption isotherm data could be well fitted by both Langmuir equation and Freundlich equation. Thermodynamic studies confirmed that the process was spontaneous and endothermic. The adsorbed amounts of Pb(II) tend to increase with the increase of pH. The adsorption kinetic data can be satisfactorily described by either of the power functions and simple Elovich equations. The desorbability of Pb(II) is about 15-20%, and it is relatively difficult for the adsorbed Pb(II) to be desorbed. The relatively low cost and high capabilities of the rice bran make it potentially attractive adsorbent for the removal of Pb(II) from wastewater.展开更多
基金supported by the National Natural Science Foundation of China(51672312,21571192,21373275)the Science and Technology Program of Wuhan(2016010101010018,2015070504020220)+1 种基金the Key Project in the National Science&Technology Pillar Program during the Twelfth Five-Year Plan Period(2015BAB01B01)the Natural Science Foundation of South-Central University for Nationalities(XTZ15016,CZP17062)~~
文摘As a two dimensional(2D)visible‐light‐responsive semiconductor photocatalyst,the photoreactivity of Bi2WO6 is not high enough for practical application owing to its limited response to visible light and rapid recombination of photogenerated electron‐hole pairs.In this paper,2D core‐shell structured Bi2WO6@Bi2S3 nanoplates were prepared by calcination of a mixture of Bi2WO6(1.3 g)and a certain amount of Na2S·9H2O(0–3.0 g)at 350°C for 2 h.The reactivity of the resulting photocatalyst materials was evaluated by photocatalytic degradation of Brilliant Red X‐3B(X3B),an anionic dye,under visible light irradiation(?>420 nm).As the amount of Na2S·9H2O was increased from 0 to 1.5 g,the degradation rate constant of X3B sharply increased from 0.40×10?3 to 6.6×10?3 min?1.The enhanced photocatalytic activity of Bi2WO6@Bi2S3 was attributed to the photosensitization of Bi2S3,which greatly extended the light‐responsive range from the visible to the NIR,and the formation of a heterojunction,which retarded the recombination rate of photogenerated electron‐hole pairs.However,further increases in the amount of Na2S·9H2O(from 1.5 to 3.0 g)resulted in a decrease of the photocatalytic activity of the Bi2WO6@Bi2S3 nanoplates owing to the formation of a photo‐inactive NaBiS2 layer covering the Bi2WO6 surface.
文摘In this study, the modified rice bran was tested to remove Pb(II) from water. Batch experiments were carried out to evaluate the adsorption characteristics of the modified rice bran for Pb(II) removal from aqueous solutions. The adsorption isotherms, thermodynamic parameters, kinetics, pH effect, and desorbability were examined. The results show that the maximum adsorption capacity of the modified rice bran was approximately 70.8 mg Pb(II)/g absorbent at temperature of 25℃ and at the initial Pb(II) concentration of 400 mg/L and pH 7.0. And the adsorption isotherm data could be well fitted by both Langmuir equation and Freundlich equation. Thermodynamic studies confirmed that the process was spontaneous and endothermic. The adsorbed amounts of Pb(II) tend to increase with the increase of pH. The adsorption kinetic data can be satisfactorily described by either of the power functions and simple Elovich equations. The desorbability of Pb(II) is about 15-20%, and it is relatively difficult for the adsorbed Pb(II) to be desorbed. The relatively low cost and high capabilities of the rice bran make it potentially attractive adsorbent for the removal of Pb(II) from wastewater.
