开放系统下方解石对邻苯二甲酸的吸附

Sorption of o-Phthalate onto Calcite in Open-System

通过批量平衡法,研究开放系统条件下方解石对邻苯二甲酸的吸附特性.结果表明:1邻苯二甲酸在方解石上的吸附3 h后渐趋平衡,一级动力学方程与二级动力学方程都能较好拟合吸附过程;2当p H从7.7增加到9.7时,邻苯二甲酸的吸附率逐渐降低,溶液中HCO-3和CO2-3的竞争效应及方解石表面的静电效应是其主导因素;3邻苯二甲酸的吸附率随离子强度升高而减少,这是由于电解质的"盐效应"作用增大了竞争离子HCO-3和CO2-3的浓度;4与间、对苯二甲酸相比,邻苯二甲酸的吸附率明显较高,可能是由于邻苯二甲酸的两个羧基距离较近,容易在方解石表面形成环状的络合物结构.通过研究邻苯二甲酸在方解石上的吸附特性,有助于了解二者的相互作用机制,为利用方解石去除环境中的邻苯二甲酸提供理论支持.

The batch sorption methods were deployed to study the sorption of o-phthalate on calcite in open-system.Results show that:1 The o-phthalate sorption reached the equilibrium within 3 hours.Both pseudo first-order and pseudo second-order models described the kinetic characteristics well; 2 The o-phthalate sorption rate decreased with p H( 7.7-9.7).This phenomenon was due to the competition effect of HCO-3and CO2-3,and the electrostatic effect on the surface; 3The o-phthalate sorption rate also decreased with the increase in ionic strength.This was due to the rise in concentration of HCO-3and CO2-3induced by salt effect; 4 Compared with m-phthalate and p-phthalate,o-phthalate sorption rate was much higher due to the proximity of its two carboxyl groups which easily formed a chelate ring of surface complex.By studying the factors that influence o-phthalate sorption onto calcite,the sorption mechanism can be well understood.This mechanism can be applied in the removal of o-phthalate from the environment.