铁改性海泡石吸附镉和砷效果及其影响因素

Adsorption Efficiency of Cadmium and Arsenic by Iron-modified Sepiolite and Its Influencing Factors

海泡石是一种纤维形态多孔的含镁硅酸盐,具有很大的比表面积,在重金属污染治理中具有很大的潜力。本实验研究天然海泡石铁改性前后对Cd2+和As3+的吸附效果及其影响因素,旨在为镉和砷复合污染的水体或土壤治理提供参考。研究结果表明铁改性海泡石形成了新的羟基键,且其表面粗糙程度提高。固液比为1:100条件下,海泡石铁改性后对As3+(20 mg/L)和Cd2+(10 mg/L)的吸附效率分别由34%和55%提高至98%和95%。与天然海泡石相比,铁改性海泡石对砷和镉的最大吸附容量约分别提高了9倍和2.5倍。pH对2种材料吸附砷和镉的效率影响较小,但在pH为6时有最佳效果。随着固液比增加,两种材料对Cd2+的吸附效率增加,但对砷的吸附效率影响较小。铁改性海泡石是一种治理镉和砷复合污染的潜在材料。

Sepiolite is a porous,magnesium-containing silicate with a large specific surface area and has great potential for the remediation of heavy metal pollution.This study investigated the adsorption effects of cadmium(Cd2+)and arsenic(As3+)before and after iron modification of natural sepiolite and its influencing factors,aiming to provide reference for the management of Cd and As combined pollution to water or soil.The results showed that the iron-modified sepiolite formed new hydroxyl bonds and its surface roughness was improved.The adsorption efficiency of As3+(20 mg/L)and Cd2+(10 mg/L)increased from 34%and 54%to 98%and 95%,respectively,when natural sepiolite was modified.The maximum adsorption capacity of iron-modified sepiolite for arsenic and cadmium was 9 times and 2.5 times higher than that of natural sepiolite respectively.The pH value had less effect on the adsorption of As and Cd by the two materials,but had the finest effect at p H 6.With the increase of solid-liquid ratio,the adsorption efficiency of two materials for Cd2+,increased,but it had little effect on the adsorption efficiency of As3+.Iron-modified sepiolite is a potential material for dealing with the combined pollution of Cd and As.