植物多酚改性膨润土吸附重金属镉实验研究

对钙基膨润土、酸活化膨润土、自制单宁酸改性膨润土,通过表征测试研究了膨润土改性后的形态结构变化。结果表明:单宁酸改性膨润土较钙基膨润土结构未发生较大变化;并分别探讨了不同投加量、反应pH及不同初始浓度对单宁酸改性膨润土吸附镉的影响。实验表明:单宁酸改性膨润土对Cd2+的吸附性能优于钙基膨润土及酸活化膨润土,在材料用量越小及反应pH越低时,单宁酸对膨润土吸附Cd2+的促进作用越明显。单宁酸改性膨润土对Cd2+的吸附能用Langmuir吸附方程进行描述,其最大吸附量约为31.25mg/g,比钙基膨润土提高了20.6%。本研究将为非金属矿物在水体及土壤重金属污染修复方面的应用提供理论基础和科学依据。

Experimental Study on Adsorption of Cadmium with Bentonite Modified by Plant Polyphenol

Characterization test was performed to study the morphological changes among calcium bentonite,acid-activated bentonite and homemade tannin-modified bentonite.The results showed that tannin-modified bentonite remained nearly unchanged structure compared with calcium bentonite.And batch equilibrium experiments of Cd2＋ adsorption by the modified bentonite were performed.Effects of dosage,pH,and initial concentration on the adsorption of Cd2＋ were studied.The results showed that the adsorption capacity of Cd2＋ with tannin-modified bentonite was greatly better than that of calcium bentonite and acid-activated bentonite.The improvement of the adsorption capacity of Cd2＋ after bentonite modified by tannin was increasingly remarkable with the decreasing dosage of tannin-modified bentonite and initial pH.The adsorption of Cd2＋ with tannin-modified bentonite fitted Langmuir adsorption isotherm,and the maximum adsorption capacity of Cd2＋ with tannin-modified bentonite was 31.25mg/g,which was 20.6％ higher than that of calcium bentonite.Concisely,this study provides theoretical foundation and scientific basis for the application of non-metallic minerals in remediation of heavy metal pollution in water and soil.