Chestnut Shell Recovery was used to Explore the Difference in the Removal Effect of Two KOH Activated Biochars on Cd in Water
In this study,two kinds of porous biochars KBC7001 and KBC7002 with high specific surface area were successfully synthesized by one-step and two-step pyrolysis using chestnut shell as raw material and KOH as activator.The product showed excellent removal ability of Cd2+ in water,and a series of batch adsorption experiments and characterization experiments were carried out to study the difference of its activation mechanism and the adsorption mechanism of two modified biochars.The results show that KBC7001 has a large specific surface area(1887.04 m2/g)and a rich pore structure,with an average pore size of 1.07 nm and a pore size mainly distributed between 0.5～2 nm.The theoretical maximum adsorption capacity of KBC7001 for Cd2+ at 308 K was 83.86 mg/g.The adsorption of Cd2+ by KBC7001 and KBC7002 is a spontaneous endothermic reaction that reaches adsorption equilibrium within 4 h.The one-step activation of KOH promoted the immobilization of O elements on biochar,so that more oxygen-containing functional groups were formed on the surface of KBC7001,which participated in the adsorption process.Recycling experiments and simulated wastewater adsorption experiments show that KBC7001 has more stable adsorption performance.In addition,KBC7001 immobilizes Cd2+ primarily by electrostatic attraction,pore filling,precipitation-complexation,and ion exchange.
NETL
NSTL
万方数据
