回收栗子壳探索两种KOH活性生物炭对水中Cd的去除效果差异  

Chestnut Shell Recovery was used to Explore the Difference in the Removal Effect of Two KOH Activated Biochars on Cd in Water

作　　者：关君男 彭书传 田丰 Guan Junnan;Peng Shuchuan;Tian Feng(Hefei University of Technology,Hefei 230041,China;Anhui Changzhiyuan Environmental Engineering Co.,Ltd.,Hefei 230041,China)

机构地区：[1]合肥工业大学,安徽合肥230041 [2]安徽长之源环境工程有限公司,安徽合肥230041

出　　处：《广东化工》2024年第4期44-48,86,共6页Guangdong Chemical Industry

基　　金：国家自然科学基金项目(41390244,41772035)。

摘　　要：本研究以栗子壳为原料,以KOH为活化剂,通过一步法和二步法热解成功合成了两种高比表面积的多孔生物炭KBC7001和KBC7002。产品表现出对水体Cd2+优异的去除能力,并进行了一系列批量吸附实验和表征实验,研究其活化机制的差异和两种改性生物炭的吸附机制。结果表明,KBC7001具有较大的比表面积(1887.04 m^(2)/g)和较丰富的孔隙结构,平均孔径为1.07 nm,孔隙大小主要分布在0.5~2 nm之间。KBC7001在308K时对Cd^(2+)的理论最大吸附量为83.86 mg/g。KBC7001和KBC7002对Cd^(2+)的吸附是一种自发的吸热反应,4 h内达到吸附平衡。KOH的一步活化促进了O元素在生物炭上的固定化,使KBC7001表面形成了更多的含氧官能团,参与了吸附过程。循环再生实验和模拟废水吸附实验表明,KBC7001具有更稳定的吸附性能。此外,KBC7001主要通过静电吸引、孔隙填充、沉淀-络合和离子交换来固定Cd^(2+)。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 Cd^(2+) 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 m^(2)/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 Cd^(2+) at 308 K was 83.86 mg/g.The adsorption of Cd^(2+)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 thethe 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 Cd^(2+)primarily by electrostatic attraction,pore filling,precipitation-complexation,and ion exchange.

关 键 词：生物炭 氢氧化钾 改性 吸附 镉 

分 类 号：X7[环境科学与工程—环境工程]