污泥复合玉米芯碳化吸附剂对Pb^(2+)的吸附特性  

Adsorption characteristics of lead(Ⅱ)in wastewater by carbonized adsorbent prepared from dewatered sludge and corncob

作　　者：李亚飞 杨毅[1,2,3] 王一博[1,4] 张亚楠 陈元 熊慧玲 LI Ya-fei;YANG Yi;WANG Yi-bo;ZHANG Ya-nan;CHEN Yuan;XIONG Hui-ling(School of Environmental & Municipal Engineering,Xi’an University of Architecture & Technology,Xi’an 710055,China;Key Laboratory of Northwest Water Resources,Environment and Ecology,Ministry of Education,Xi’an 710055,China;Experimental Teaching Demonstration Center of National Environmental Specialty,Xi’an University of Architecture &Technology,Xi’an 710055,China;Shaanxi Environmental Monitoring Center Station,Xi’an 710075,China)

机构地区：[1]西安建筑科技大学环境与市政工程学院,陕西西安710055 [2]西北水资源与环境生态教育部重点实验室,陕西西安710055 [3]西安建筑科技大学国家级环境类专业实验教学示范中心,陕西西安710055 [4]陕西省环境监测中心站,陕西西安710075

出　　处：《应用化工》2021年第5期1211-1217,共7页Applied Chemical Industry

基　　金：国家自然科学基金资助项目(21407119);陕西省教育厅重点实验室科研计划项目(18JS055);西安建筑科技大学预研基金项目(ZR18032)。

摘　　要：采用城市污水处理厂脱水污泥和玉米芯复合碳化制备吸附剂,利用BET、SEM和FTIR对吸附剂进行表征,通过吸附因素影响实验、解吸实验、选择性吸附实验、吸附动力学和等温模型拟合考察其对废水中Pb^(2+)的吸附特性,并对实际废水进行了吸附研究。结果表明,污泥复合玉米芯碳化吸附剂比表面积为991.20 m^(2)/g,以中孔为主,其对模拟废水中Pb^(2+)的较佳吸附条件:初始pH、吸附温度和吸附时间分别为4.0~5.5、25℃和4.0 h,当Pb^(2+)初始浓度为10 mg/L、较佳吸附剂投加量为6 g/L时,Pb^(2+)去除率为90.10%,吸附量为1.50 mg/g。经0.5 mol/L的HCl解吸6次,吸附剂对Pb^(2+)的去除率仍达92%以上。污泥复合玉米芯碳化吸附剂对Pb^(2+)的吸附符合准二级动力学模型(R2为0.9971~0.9995)和Freundlich吸附等温模型(R2为0.9920~0.9966),为非均匀化学吸附,羟基和羧基起主要作用。Cu^(2+)、Cd^(2+)和Ni^(2+)对Pb^(2+)产生竞争吸附作用,选择性吸附顺序为:Cu^(2+)>Pb^(2+)>Ni^(2+)>Cd^(2+)。实际废水(COD、Pb^(2+)和Cu^(2+)初始浓度分别为563,23.20,29.86 mg/L)处理结果表明,当吸附剂投加量为32 g/L时,Pb^(2+)去除率达96.10%,剩余浓度为0.90 mg/L,达到《污水综合排放标准》(GB 8978—1996)第一类污染物最高允许排放浓度限值,此时Cu^(2+)几乎被完全吸附。The lead(Ⅱ)adsorption in wastewater by carbonized adsorbent prepared from corncob and dewatered sludge of municipal sewage treatment plant was studied by the experiments on the factors affecting adsorption(initial pH,adsorbent dosage,adsorption temperature and adsorption time),desorption experiments,selective adsorption experiments,adsorption kinetic model fitting and adsorption isotherm model fitting.The adsorbent was characterized by BET,SEM and FTIR.And the adsorption of lead(Ⅱ)in actual wastewater was also studied.The results show that the carbonized adsorbent prepared from dewatered sludge and corncob has a specific surface area of 991.20 m^(2)/g,mainly mesopores.The preferred conditions of lead(Ⅱ)adsorption are as follows:initial pH is 4.0~5.5,adsorption temperature is 25℃and adsorption time is 4.0 h,respectively.Under this condition,when the initial lead(Ⅱ)concentration is 10 mg/L,with the preferred adsorbent dosage of 6 g/L,the removal rate of lead(Ⅱ)can reach 90.10%and adsorption capacity is 1.50 mg/g.After desorption of 0.5 mol/L HCl for 6 times,the removal rate of lead(Ⅱ)by the adsorbent can still reach over 92%.The lead(Ⅱ)adsorption process by the carbonized adsorbent prepared from dewatered sludge and corncob is more in line with the quasi-secondary kinetic model(R 2=0.9971~0.9995)and Freundlich adsorption isotherm model(R 2=0.9920~0.9966),which indicates that the adsorption type is heterogeneous chemisorption.The hydroxyl and carboxyl groups are involved in the lead(Ⅱ)adsorption.Coexisting metal ions(Cu(Ⅱ),Cd(Ⅱ)and Ni(Ⅱ))compete for the adsorption of lead(Ⅱ),and the selective adsorption order of metal ions on the carbonized adsorbent is Cu(Ⅱ)>Pb(Ⅱ)>Ni(Ⅱ)>Cd(Ⅱ).The results of actual wastewater treatment show that when the adsorbent dosage is 32 g/L,the lead(Ⅱ)concentration after adsorption is 0.90 mg/L with a removal rate of 96.10%,which reaches the maximum allowable discharge concentration of class I pollutant in the integrated wastewater discharge standard(GB 897

关 键 词：吸附剂 污泥 玉米芯 Pb^(2+) 实际废水 

分 类 号：TQ085[化学工程] TQ424