羧甲基纤维素钠炭化物吸附水中铅离子研究  

Study on Lead Ion Adsorption on Carbonized Sodium Carboxymethyl Cellulose

作　　者：艾硕 玉万国[1] 黄承都[1] AI Shuo;YU Wanguo;HUANG Chengdu(Department of Biological and Chemical Engineering,Guangxi University of Science and Technology,Liuzhou 545006,China)

机构地区：[1]广西科技大学生物与化学工程学院,广西柳州545006

出　　处：《水处理技术》2022年第10期57-62,共6页Technology of Water Treatment

基　　金：国家自然科学基金项目(32060205);广西自然科学基金(2018GXNSFBA281147)。

摘　　要：通过炭化羧甲基纤维素钠(CMC)制备了新型吸附剂,脱铅率高达98.7%。SEM和TEM测试结果表明该吸附剂含有大量内壁光滑的椭球形大孔。TG-MS结果表明CMC于300℃下剧烈分解,放出CO、CO_(2)、水蒸汽。红外及拉曼光谱显示,炭化时羟基和糖苷键断裂,碳原子重排为芳环,羧酸根减少。初始铅浓度为50 mg/L时,平衡吸附量达到最大值171 mg/g。Zeta电位测试结果表明,吸附剂的等电点高达5.6。此外,铅离子水解产生的质子会与吸附剂表面-COO^(−)基团结合生成-COOH,导致表面电位升高,减弱了吸附剂对铅离子的静电引力。XPS测试结果表明铅离子在吸附过程中得到电子。使用EDTA溶液可洗脱吸附剂表面的铅,实现吸附剂的再生。再生5次后,脱铅率基本不变。本研究可为重金属吸附剂的表面修饰及多孔碳材料的制备提供理论指导。Sodium carboxymethyl cellulose(CMC)was carbonized to prepare a novel adsorbent,and the lead removal rate was up to 98.7%.SEM and TEM results showed that the adsorbent contained a large number of ellipsoidal macropores with smooth inner walls.TG-MS measurement results show that CMC decomposed dramatically at 300℃ to release CO,CO_(2),and vapor.Infrared and Raman spectra showed that hydroxyl and glycoside bonds were broken during carbonization,the carbon atoms were rearranged to form aromatic rings,and the number of carboxylate groups decreased.Under the condition of initial lead content of 50 mg/L,the equilibrium adsorption capacity reached a maximum of 171 mg/g.Zeta potential measurement results showed that the isoelectric point of the adsorbent was as high as 5.6.In addition,the protons generated from the hydrolysis of lead ions would bond with-COO^(−)groups on the surface of the adsorbent to yield-COOH,increasing the surface potential and weakening the electrostatic attraction to lead ions.XPS measurement results showed that electrons were obtained by lead ions during the adsorption process.The lead adsorbed on the surface of the adsorbent could be eluted with a dilute EDTA solution for the regeneration of adsorbent.After the adsorbent was regenerated five times,the removal rate for lead was almost kept constant.This study may shed light on the surface modification of heavy-metal adsorbents and preparation of porous carbon materials.

关 键 词：铅 吸附 炭化 羧酸根 ZETA电位 

分 类 号：TQ424[化学工程]