Arsenic(As)contamination in groundwater is a major problem in many countries,which causes serious health issues.In this paper,a novel method has been developed for the simultaneous removal of ROX and As(Ⅲ/Ⅴ)using th...Arsenic(As)contamination in groundwater is a major problem in many countries,which causes serious health issues.In this paper,a novel method has been developed for the simultaneous removal of ROX and As(Ⅲ/Ⅴ)using the modified sorghum straw biochar(MSSB).The MSSB was characterized by X-ray diffraction,scanning electron microscopy,Fourier Transform Infrared,and Brunauer–Emmet–Teller(BET)surface area.The removal performance of MSSB for ROX,arsenite[As(Ⅲ)],and arsenate(As(Ⅴ))was investigated using batch experiments.At pH of 5,the arsenic concentration of 1.0 mg/L,adsorbent dose of 1.0 g/L,the maximum adsorptioncapacities of ROX,As(Ⅲ),and As(Ⅴ)were 12.4,5.3,and 23.0 mg/g,respectively.The adsorption behaviors were fit well with the Langmuir and the pseudo-second-order rate model.The results showed that MSSB acted as a highly effective adsorbent to simultaneously remove the composite pollution system consisted of ROX and As(Ⅲ/Ⅴ)in aqueous solutions,providing a promising method in environmental restoration applications.展开更多
The effects of operating conditions and pre-densification on the torrefaction performance parameters and the properties of the torrefied sorghum straw were studied.A full-factor experiment was performed on a fixed tub...The effects of operating conditions and pre-densification on the torrefaction performance parameters and the properties of the torrefied sorghum straw were studied.A full-factor experiment was performed on a fixed tube furnace,in which sorghum straw powder and pellets were heated to 230℃,260℃,280℃ and 300℃ at 2.5℃/min,5℃/min and 7.5℃/min,respectively.The pyrolysis characteristics of the sorghum straw torrefied under various operating conditions were complemented by thermogravimetric analysis.It was observed that the high temperature led to the high calorific value of the torrefied sorghum straw with an acceptable mass and energy yield.The sorghum straw torrefied at a temperature above 280℃ had a higher heating value(HHV)that was comparable to that of the low rank coal while maintaining its energy yield above 85%.The results suggested that temperature was an important factor determining the properties of the torrefied products,and the heating rate would affect the internal temperature of the torrefied biomass by affecting the heat transfer during the torrefaction.The energy densification index of the pellets decreased uniformly as the heating rate increased proportionally,indicating that pre-densification can be used as a potential method to solve the heat transfer delay in the fixed reactors at high heating rates,especially for high temperatures.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 41773136 and41703129)Innovation Talent Support Project of Liaoning (Grant No.LR2017073)+1 种基金the National Key Rand D Program of China (No.2017YFD0800301)the basic research projects of Source-sink transformation of arsenic and roxarsone in sediments (XXLJ2019007)。
文摘Arsenic(As)contamination in groundwater is a major problem in many countries,which causes serious health issues.In this paper,a novel method has been developed for the simultaneous removal of ROX and As(Ⅲ/Ⅴ)using the modified sorghum straw biochar(MSSB).The MSSB was characterized by X-ray diffraction,scanning electron microscopy,Fourier Transform Infrared,and Brunauer–Emmet–Teller(BET)surface area.The removal performance of MSSB for ROX,arsenite[As(Ⅲ)],and arsenate(As(Ⅴ))was investigated using batch experiments.At pH of 5,the arsenic concentration of 1.0 mg/L,adsorbent dose of 1.0 g/L,the maximum adsorptioncapacities of ROX,As(Ⅲ),and As(Ⅴ)were 12.4,5.3,and 23.0 mg/g,respectively.The adsorption behaviors were fit well with the Langmuir and the pseudo-second-order rate model.The results showed that MSSB acted as a highly effective adsorbent to simultaneously remove the composite pollution system consisted of ROX and As(Ⅲ/Ⅴ)in aqueous solutions,providing a promising method in environmental restoration applications.
基金This work was carried out in the Chinese Academy of Agricultural Engineering under the guidance of Dr.Zonglu YaoThe first authors thank the Chinese Academy of Agricultural Sciences and the Chinese Academy of Agricultural Engineering for their financial support。
文摘The effects of operating conditions and pre-densification on the torrefaction performance parameters and the properties of the torrefied sorghum straw were studied.A full-factor experiment was performed on a fixed tube furnace,in which sorghum straw powder and pellets were heated to 230℃,260℃,280℃ and 300℃ at 2.5℃/min,5℃/min and 7.5℃/min,respectively.The pyrolysis characteristics of the sorghum straw torrefied under various operating conditions were complemented by thermogravimetric analysis.It was observed that the high temperature led to the high calorific value of the torrefied sorghum straw with an acceptable mass and energy yield.The sorghum straw torrefied at a temperature above 280℃ had a higher heating value(HHV)that was comparable to that of the low rank coal while maintaining its energy yield above 85%.The results suggested that temperature was an important factor determining the properties of the torrefied products,and the heating rate would affect the internal temperature of the torrefied biomass by affecting the heat transfer during the torrefaction.The energy densification index of the pellets decreased uniformly as the heating rate increased proportionally,indicating that pre-densification can be used as a potential method to solve the heat transfer delay in the fixed reactors at high heating rates,especially for high temperatures.
