酸热活化、有机化、柱撑改性海泡石对土壤中钒的吸附固定

采用酸热活化、巯基有机化、羟基铁铝柱撑3种方法对天然海泡石进行改性，研究不同改性方法对海泡石结构及比表面积的影响，并将其作为吸附剂加入土壤，采用批量吸附试验考察吸附剂添加量、吸附时间、初始钒V（Ⅴ）离子浓度等因素对吸附效果的影响，探究添加改性海泡石的土壤对V（Ⅴ）的吸附效果及机理。研究结果表明:改性后海泡石比表面积增大，部分结构发生改变，吸附能力增强；添加羟基铁铝柱撑、酸热活化、巯基有机化改性海泡石的土壤对V（Ⅴ）的最大吸附量分别为2159.71，1619.57，936.57 mg/kg；吸附方式为单分子层物理吸附；解吸试验表明，添加羟基有机化改性海泡石的土壤解吸率最高，酸热活化和羟基铁铝柱撑海泡石次之。添加柱撑及酸热活化海泡石的土壤对V的吸附效果较好，用量5%时对V（Ⅴ）的固化率分别为30.24%、22.67%，但柱撑海泡石的稳定性仍有待提升。

ADSORPTION AND FIXATION OF VANADIUM IN SOIL BY SEPIOLITES MODIFIED BY ACID-THERMAL ACTIVATION,SULFHYDRYL ORGANISATION AND HYDROXYL IRON-ALUMINUM PILLARING

The effects of acid-thermal activation, sulfhydryl organisation and hydroxyl iron-aluminum pillaring modified sepiolite as adsorbent to fix V(Ⅴ) in soil were studied. Batch adsorption tests were carried out to investigate the effects of adsorbent addition, adsorption time, and initial V(Ⅴ) concentration on adsorption. The Langmuir and Freundlich isothermal adsorption curves were used to explore the adsorption effect and mechanism of soil system added with modified sepiolite on V(Ⅴ). The results showed that after modification the specific surface area of sepiolite increased, the structure changed, and the adsorption capacity enhanced. The maximum adsorption amount of hydroxyl iron-aluminum pillaring modified sepiolite (F-SEP), acid-thermal activation (H-SEP), and sulfhydryl organisation (S-SEP) applied soils were 2159.71, 1619.57, 936.57 mg/kg, respectively. The adsorption of V(Ⅴ) in soil by modified sepiolite was a single molecular layer physical adsorption. The desorption test showed that S-SEP had the highest desorption rate, while the desorption rate of F-SEP and H-SEP was lower. The H-SEP and F-SEP had better adsorption effect on V(Ⅴ) in soil than S-SEP, when the dosage was 5%, their solidification rate was 30.24% and 22.67%, respectively. Thus, sepiolite modified by acid-thermal activation, sulfhydryl organisation and hydroxyl iron-aluminum pillaring could be used as potential adsorbent for the treatment of vanadium polluted soils, but the stability of F-SEP still needs to be improved.