Nitrate removal from aqueous solutions by magnetic cationic hydrogel:Effect of electrostatic adsorption and mechanism

作     者：Junyi Li Shuoxun Dong Yili Wang Xiaomin Dou Haotian Hao Junyi Li;Shuoxun Dong;Yili Wang;Xiaomin Dou;Haotian Hao

作者机构：College of Environmental Science and EngineeringBeijing Key Lab for Source Control Technology of Water PollutionBeijing Forestry UniversityBeijing 100083China Center for Water and EcologyState Key Joint Laboratory of Environment Simulation and Pollution ControlSchool of EnvironmentTsinghua UniversityBeijing 100084China Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China 

出 版 物：《Journal of Environmental Sciences》 (环境科学学报（英文版）)

年 卷 期：2020年第32卷第5期

页      面：177-188页

核心收录：

学科分类：0830[工学-环境科学与工程（可授工学、理学、农学学位）] 08[工学] 0815[工学-水利工程] 

基　　金：supported by the National Key Research and Development Program of China(No.2017YFC0505303) the China Major Science and Technology Project of Water Pollution Control and Management,China(No.2017ZX07202003) the National Natural Science Foundation of China(Nos.51478041 and 51678053) 

主　　题：Adsorption Nitrate removal Low concentration Electrical stern layer Magnetic cationic hydrogel 

摘      要：Excessive nitrate(NO3-)is among the most problematic surface water and groundwater pollutants.In this study,a type of magnetic cationic hydrogel(MCH)is employed for NO3-adsorption and well characterized herein.Its adsorption capacity is considerably pHdependent and achieves the optimal adsorption(maximum NO3--adsorption capacity is95.88±1.24 mg/g)when the pH level is 5.2-8.8.The fitting result using the homogeneous surface diffusion model indicates that the surface/film diffusion controls the adsorption rate,and NO3-approaches the center of MCH particles within 30 min.The diffusion coefficient(Ds)and external mass transfer coefficient(kF)in the liquid phase are1.15×10-6 cm2/min and 4.5×10-6 cm/min,respectively.The MCH is employed to treat surface water that contains 10 mg/L of NO3-,and it is found that the optimal magnetic separation time is 1.6 min.The high-efficiency mass transfer and magnetic separation of MCH during the adsorption-regeneration process favors its application in surface water treatment.Furthermore,the study of the mechanism involved reveals that both-N+(CH3)3 groups and NO3-are convoluted in adsorption via electrostatic interactions.It is further found that ion exchange between NO3-and chlorine occurs.