Study on the adsorption of phosphate over biochar-based adsorbents from peanut shell and orange peel in water
Yue Zhao, Xue He, Kezhen Qi, Amir Zada, Jing Pan
Abstract
ABSTRACT The presence of complex functional groups and a well-developed pore structure make biochars highly effective in the removal of hazardous substances from water. In this work, peanut shell and orange peel biochars were produced by slow pyrolysis at different temperatures (300°C, 400°C, 500°C) for 6 h. The prepared biochars were used to treat phosphate in water to explore the effect of contact time and initial concentration of phosphate on adsorption performance. The kinetic models were fitted to study the adsorption mechanisms. The results showed that the highest yields of peanut shell (86.7%) and orange peel biochars (81.2%) were achieved at 400°C and 300°C, respectively. 5.0 g of peanut shell biochars removed about 5.94 mg/g phosphate in 26 h and the removal rate was 83.2%, while the same amount of orange peel biochars removed about 5.79 mg/g phosphate in 26 h and the removal rate was 81.1%. The adsorption processes of phosphate by peanut shell and orange peel biochars fitted with the secondary kinetic models, which were dominated by chemical adsorption.