不同地域白云石对铅吸附特性的研究

Adsorption Characteristics of Lead from Dolomite from Different Areas

以3种不同来源白云石为吸附剂,结合zeta电位等分析方法,通过吸附动力学及等温吸附试验研究白云石对Pb^(2+)的吸附特性。结果表明:1#~3#白云石对Pb^(2+)吸附最佳p H值为5。白云石zeta电位与其吸附效果密切相关,Pb^(2+)去除率与白云石zeta电位的变化趋势相似;随着Pb^(2+)去除率的增加并逐渐接近最大值,1#、2#、3#白云石等电点明显向碱性范围移动。准二级动力学模型能够更好地描述白云石对溶液中Pb^(2+)的吸附动力学特征,其结果与试验数值更为接近,该吸附过程主要以化学吸附为主。Langmuir方程能够较好地描述白云石对Pb^(2+)的吸附行为,吸附过程主要以单层吸附为主,1#、2#、3#白云石拟合得到最大吸附容量分别为35.798 1 mg/g、31.711 4 mg/g、33.752 2 mg/g。1#白云石呈现出最优的去除效果,为最佳吸附剂。

Using three different sources of dolomite as adsorbent,combined zeta potential and other analytical methods,adsorption kinetics and isothermal adsorption experiments were conducted to study the adsorption characteristics of dolomite on lead ions.The results showed that the optimal pH for adsorption of Pb2+from 1#to 3#dolomite was 5.The zeta potential of dolomite was closely related to its adsorption effect,and the removal rate of Pb2+was similar to that of dolomite zeta potential.With the increase of Pb2+removal rate and gradually approaching the maximum value,the isoelectric point of dolomite 1#、2#、3#moved to the alkaline range obviously.The pseudo-second-order kinetics model can better described the adsorption kinetics of Pb2+in dolomite solution.The result was closer to the experimental value,and the adsorption process was dominated by chemical adsorption.The Langmuir equation can described the adsorption behavior of dolomite to Pb2+.The adsorption process was mainly monolayer adsorption,and the maximum adsorption capacity of 1#、2#、3#dolomite fittings could reached 35.798 1 mg/g,31.711 4 mg/g,33.752 2 mg/g,respectively.1#dolomite presents the best removal effect and is the best adsorbent.