改性花生壳生物质炭对土壤中Cr(Ⅵ)的吸附机制

Study on the Adsorption Performance of Biomass Carbon from the Modified Peanut Hull to Cr(Ⅵ)in Soil

为了提高土壤中重金属Cr(Ⅵ)的去除率,采用简单高效的吸附法,筛选廉价且吸附效果好的吸附剂成为土壤中重金属去除的研究热点.以农业废弃物花生壳为原料,用FeCl_(3)和ZnCl_(2)改性得到改性花生壳生物质炭(MPS),将其用于土壤中重金属Cr(Ⅵ)吸附研究实验中.考察pH值、投加量、反应温度、初始浓度和反应时间对Cr(Ⅵ)去除率的影响,并对吸附机制进行探讨.结果表明,在pH值为3时,MPS添加量为土壤质量的5%,反应温度为30℃,初始质量浓度为120mg·L^(-1),反应时间为120min,得到的最高去除率为98.23%.参数拟合结果表明,改性花生壳生物质炭Langmuir吸附模型的相关系数R^(2)高达0.993,准二级动力学拟合的相关系数R^(2)为0.987,表明是单分子层反应.

In order to improve the removal rate of heavy metal Cr(VI)in soil,the use of simple and efficient adsorption methods to screen cheap and effective adsorbents has become a research hotspot for heavy metal removal in soil.This study uses agricultural waste peanut shells as raw materials and modifies them with FeCl_(3)and ZnCl_(2)to obtain the biochar from the modified peanut shell(MPS),which is used in experiments on the adsorption of heavy metal Cr(VI)in soil.The effects of pH value,dosage,reaction temperature,initial concentration,and reaction time on Cr(VI)removal rate were investigated,and the adsorption mechanism was explored.The results showed that at a pH of 3,the addition of MPS was 5%of the soil mass,the reaction temperature was 30℃,the initial concentration was 120 mg·L^(-1),and the reaction time was 120 minutes.The highest removal rate obtained was 98.23%.The parameter fitting results indicate that the correlation coefficient R^(2)of the Langmuir adsorption model for modified peanut shell biochar is as high as 0.993,and the correlation coefficient R^(2)of the quasi second-order kinetic fitting is 0.987,indicating a single-molecule layer reaction.