载镁活化天然沸石处理高氟地下水实验研究

Experimental Study on Fluoride Removal from Groundwater by MgCl_2-activated Natural Zeolite

为了研究地下水中阴离子对载镁活化天然沸石除氟效果的影响,考察了4种主要阴离子——Cl-,HCO3-,SO42-,PO43-的影响,并分析了吸附剂的除氟机理及表面结构和成分。结果表明:对于初始氟浓度不同的水样,随着阴离子浓度的增加,吸附剂对氟的去除效率逐渐降低。Cl-对吸附剂除氟效果影响较小,氟去除率降低较慢;随着HCO3-浓度的增大(由100 mg/L到1 000 mg/L),水样pH缓慢由7.48增大到9.44,而氟去除率则由63.78%缓慢下降到52.70%(2 mg/L);SO42-及PO43-对改性沸石除氟效果影响较大,氟去除率降低较快,且SO42-的影响大于PO43-。所以,镁改性天然沸石对该4种阴离子的吸附顺序是:SO42->PO43->HCO3->Cl-。

Effects of 4 anions in groundwater such as Cl-,HCO3-,SO42-,PO43-on the capacity of defluoridation of MgCl2activated natural zeolite were investigated.Mechanism of defluoridation and surface composition and structure of adsorbent were analyzed.Results showed that removal efficiencies of fluoride for different initial fluoride concentrations of water samples were gradually reduced with concentrations of anions increasing.Effects of Cl-on the adsorbent were tiny with slower decrease of fluorine removal rate.With the increase of HCO3-concentration from 100 mg/L to 1 000 mg/L,pH of water samples slowly increased to 9.44 from 7.48,and removal efficiency of fluoride tardily declined to 52.70% from 63.78%（2 mg/L）.Effects of SO42-and PO43-on the capacity of defluoridation of the modified zeolite were greater,with rapidly decrease of fluorine removal rate.The impact of SO42-was greater than PO43-.The adsorption capacity of MgCl2-activated natural zeolite on the anions is PO43-SO42-HCO3-Cl-.