胶州湾沉积物表面酸碱性质及对铜的吸附

摘要

选取胶州湾海域2个站点的沉积物进行了表面酸碱电位滴定实验,并考察了人工海水介质中对铜离子的吸附性能,比较了介质的盐度和温度等对吸附动力学曲线和吸附等温线的影响.结果发现:2个站点的沉积物随pH值由3增大到10表面质子电荷密度的值由正转负,零净质子电荷点pHPZNPC均在4.0～4.5之间,表面位浓度Hs在1.34×104～1.90×10-4 mol·L-1之间；沉积物对铜离子的动力学吸附曲线可用伪一级动力学方程、伪二级动力学方程、Elovich方程、双常数速率方程拟合,其中伪二级动力学方程符合较好,吸附在2h左右达到平衡；吸附等温线可用Langmuir等温式拟合.零净质子电荷点低、表面位浓度大的沉积物对铜离子的吸附能力较强.蒸馏水介质中,沉积物对铜离子的饱和吸附量小于在稀释人工海水中和人工海水中的结果；较高的温度使饱和吸附量增大.%In this paper, potentiometric titrations was used to study the surface acid-base properties of two sediments sampled from Jiaozhou Bay. The sorption kinetics and thermodynamics of copper ( II ) onto the sediments were also investigated. The test results'showed that with Ph increasing from 3 to 10, the sorption density of proton on the surface changed from positive to negative. The points of zero net proton charge (pHpzMc) of the sediments were between 4. 0 and 4. 5, and the surface reactive concentrations (Hs) were between 1. 34×10-4 and 1. 90×10-4 mol ? L-1. The sorption equilibrium of copper( II) on the sediments could be established within 2 h. Compared to the pseudo-first-order kinetic rate equation, two-constant rate equation and Elovich equation, the pseudo-second-order kinetic rate equation appeared to fit the kinetic data better. The sorption isotherms could be described by the Langmuir isotherm. The sediment with lower pHpzNrcand higher Hs could adsorb more copper( II ). The sorption was found to be favored by a higher salinity and higher temperature.