改性茶叶渣/膨润土复合材料对饮水中硝酸盐的吸附性能

Adsorption characteristics of nitrate onto modified tea residue/bentonite composite in aqueous solution

利用茶叶渣和膨润土为原料,通过水热合成法制备新型复合材料,评价该材料对饮水中硝酸盐的吸附效果。试验结果表明,材料的制备条件对硝酸盐去除率有较大影响,茶叶渣和膨润土经5%盐酸酸化后,将1.5g的混合粉末(茶叶渣和膨润土的质量比为1∶1)加入到100mL浓度为1.0mol/L的氯氧化锆溶液中,经0.03mol/L的十六烷基三甲基溴化铵修饰后制备的复合材料,对25mg/L硝酸盐的吸附效果最好,其最大去除率为44.9%。相对原材料,硝酸盐去除率分别提高6.4倍和7.9倍。另外,溶液特征也对硝酸盐去除率有一定影响,当pH为2.0、吸附剂剂量为20g/L、反应时间为120min、硝酸盐初始浓度为150mg/L时,改性茶叶渣/膨润土复合材料对硝酸盐的最大吸附量为13.07mg/g。

Modified tea residue/bentonite composite as a novel adsorbent was prepared from tea residue and bentonite and assessed its removing rate of nitrate in aqueous solution.The results indicated that the preparation condition had obvious effect on the removing rate of nitrate.After tea residue and bentonite was acid by 5% hydrochloric acid,1.5g mixed powder（the ratio of tea to bentonite was 1∶1）was reacted with 100 mL zirconium chloride solution whose concentration was 1.0mol/L and modified by 0.03mol/L CTMB solution.The composite had the highest removing rate 44.9%.Comparison to tea residue and bentonite,the removing rate of composite for nitrate increased 6.4and 7.9times,respectively.Besides,solution condition had certain effect on the removing rate of composite for nitrate.When the pH value was 2.0,dosage was 0.2g,reaction time was 120 min,the initial concentration of nitrate was 150mg/L,the highest adsorption capacity13.07mg/g was got.