热酸处理凹凸棒石黏土对Pb^(2+)吸附性能的研究

Study on Adsorption Properties of Heat-and Acid-treatment Palygorskite Clays for Pb^(2+)

考察了吸附时间、加入量、粒径和溶液pH值等因素对凹凸棒石黏土(凹土)吸附Pb2+性能的影响。结果表明,除溶液pH值外,其它因素数值的增大,均可提高凹土对Pb2+的吸附率。随着热处理温度的升高,凹土对Pb2+的吸附率呈现先增大后减小的变化趋势;而随着酸处理浓度的增大,凹土对Pb2+的吸附率呈现先减小后增大的变化趋势。在Pb2+初始浓度为688mg/L、吸附液pH值为6.50、凹土粒径为200目、加入量为0.15g和吸附时间4h时,热处理温度300℃和酸处理浓度12mol/L时的凹土,对Pb2+的吸附率分别达到86.91%和84.52%。凹土样品经盐酸洗脱后可重复使用,重复使用性能依次为:浓盐酸处理土>300℃处理土>原土。

The effects of adsorption time, pH value of adsorption solution, amount and mesh of clay on adsorption properties of nature palygorskite clay for Pb^2＋ were studied. The results indicated that increase adsorption time, amount and mesh of clay are benefited for increase of adsorption capacities of nature palygorsldte clay for Pb^2＋, The adsorption capacities of heat-treated palygorsldte clay for Pb^2＋ increase from 100℃ to 300℃, and then decrease with further increasing heated temperature. The adsorption capacities of acid-treated palygorskite clay for Pb^2＋ decrease with the increase of HCl concentration from 2 mol/L to 4 mol/L, and then increase with further increasing HCl concentration. In the conditions of mesh of palygorskite clay is 200, amount of palygorskite clay is 0.15g, adsorption time is 4h, pH value of initial adsorption solution is 6.50 and Pb^2＋ concentration of adsorption solution is 688mg/L, the adsorption capacity of heat-treated and acid-treated palygorskite clays for Pb^2＋ is reached 86.91% and 84.52%, respectively. Natural, heat and acid activated treatment palygorskite clays can be reused. The properties of reuse are in the order of HCl-treated palygorskite 〉 300℃ -treated palygorskite 〉 non-treated palygorskite.