煤系腐植酸磁性颗粒对水中Pb^(2+)和Hg^(2+)的选择性吸附  

Humic acid magnetic nanoparticles for the selective removal of Pb^(2+)and Hg^(2+) in water

作　　者：万克记 范津津 王国强 许恩乐 贺琼琼[1] 苗真勇[1,2] 张明亮 WAN Keji;FAN Jinjin;WANG Guoqiang;XU Enle;HE Qiongqiong;MIAO Zhenyong;ZHANG Mingliang(National Engineering Research Center of Coal Preparation and Purification,China University of Mining and Technology,Xuzhou 221116,China;School of Chemical Engineering&Technology,China University of Mining and Technology,Xuzhou 221116,China;Inner Mongolia Yitai Jingyue Suancigou Coal Co.,Ltd.,Ordos 010300,China)

机构地区：[1]中国矿业大学国家煤加工与洁净化工程技术研究中心,江苏徐州221116 [2]中国矿业大学化工学院,江苏徐州221116 [3]内蒙古伊泰京粤酸刺沟矿业有限公司,内蒙古鄂尔多斯010300

出　　处：《煤炭学报》2021年第9期2746-2754,共9页Journal of China Coal Society

基　　金：国家自然科学基金资助项目(52004280);江苏省自然科学基金资助项目(BK20190629);国家重点研发计划资助项目(2019YFC1904301)。

摘　　要：由于重金属的难降解性,为避免治理过程中的污染转移,重金属的资源化回收是实现环境与经济效益双赢的有效途径,这就要求吸附剂对目标重金属具有一定的吸附选择性。通过羟甲基化改性提高煤系腐植酸(HA)表面含氧基团密度,形成对重金属吸附的多齿配位结构,来提高HA吸附选择性。改性后的腐植酸进一步与Fe_(3)O_(4)共沉淀,生成具有吸附速率快、选择性高且易于固液分离的羟甲基化煤系腐植酸磁性颗粒(OHA-MNPs),用于废水中重金属的深度分离。对吸附剂进行系统表征,并研究其吸附动力学、吸附热力学、微观吸附机制和多金属共存溶液体系中Pb^(2+)和Hg^(2+)的吸附选择性。结果表明OHA-MNPs表面腐植酸含量约为9.81%,颗粒粒径主要分布于7~11 nm,具有很好的溶液分散性;Langmuir和准二级动力学模型能够准确的描述OHA-MNPs对Pb^(2+)或Hg^(2+)的吸附热力学和动力学;OHA-MNPs对Pb^(2+)或Hg^(2+)的吸附作用以高密度含氧基团多齿络合配位为主,还伴有酸性基团离子交换和静电吸附;在模拟多金属离子共存废水中,OHA-MNPs对Pb^(2+)和Hg^(2+)均表现出较高的吸附选择性,吸附序列满足Hg^(2+)>Pb^(2+)Cu^(2+)Ni^(2+)/Cd^(2+),且在总阳离子质量浓度是Pb^(2+)的44.78倍的实际酸性矿井废水中,能够对93.76%的Pb^(2+)选择性去除。OHA-MNPs同时具有良好的再生能力,是一种高效、绿色、低成本重金属吸附剂。Because of the non-degradation of heavy metals(HMs),the control on the pollution transfer of HMs in water treatment,and their recycling utilization would be an effective way to achieve a win-win situation of environmental and economic benefits.In this case,the adsorbent with a selectivity for the target heavy metals is required.Therefore,the density of oxygen-containing functional groups on the surface of humic acid(HA)was improved by hydroxymethylation modification to promote the formation of multi-coordination structure,which had a high adsorption stability and affinity towards certain HMs.Finally,the hydroxymethylated HA magnetic nanoparticles(OHA-MNPs)with high selectivity and easy solid-liquid separation were prepared by co-precipitation,which was used for the deep removal of heavy metals in wastewater.The characterization of adsorbent,adsorption kinetics,adsorption thermodynamics,adsorption mechanism,adsorption selectivity for Pb^(2+)and Hg^(2+)under competitive adsorption,and the regeneration of adsorbent were studied.The results show that the content of HA attached on the surface of OHA-MNPs is about 9.81%.The particle size of adsorbent is mainly distributed in 7-11 nm,which shows good dispersion.The pseudo-second order kinetics and Langmuir adsorption model could well describe the adsorption kinetics and thermodynamics of Pb^(2+)or Hg^(2+)on OHA-MNPs.The adsorption of OHA-MNPs towards Pb^(2+)or Hg^(2+)is mainly attributed to the coordination of oxygen-containing functional groups,accompanied by ion exchange and electrostatic adsorption.In the solution with mixed metals,OHA-MNPs has a high selectivity for Pb^(2+)and Hg^(2+)and the selective adsorption sequence is Hg^(2+)>Pb^(2+)Cu^(2+)Ni^(2+)/Cd^(2+).About 93.76%of Pb^(2+)can be selectively removed in acid mine wastewater with total cation concentration 44.78 times that of Pb^(2+).Besides,OHA-MNPs also has good regeneration ability.Therefore,OHA-MNPs is a kind of efficient,green and low-cost adsorbent for the removal of heavy metals in wastewater.

关 键 词：煤系腐植酸 磁性纳米颗粒 羟甲基化 重金属吸附 酸性矿井废水 

分 类 号：TD984[矿业工程—选矿]