阴阳离子种类对荷正电纳滤膜分离NH4^+性能的影响  

Effect of anions and cations on performance of NH4^+separation by positively charged nanofiltration membrane

作　　者：刘曼曼 莫恒亮 陈亦力 文剑平[2] 李锁定 丑树人 俞开昌[2] 吴文辉 孟佳意 LIU Manman;MO Hengliang;CHEN Yili;WEN Jianping;LI Suoding;CHOU Shuren;YU Kaichang;WU Wenhui;MENG Jiayi(Beijing Origin Water Membrane Technology Company Limited,Beijing 101400,China;Beijing Origin Water Technology Company Limited,Beijing 102206,China)

机构地区：[1]北京碧水源膜科技有限公司,北京101400 [2]北京碧水源科技股份有限公司,北京102206

出　　处：《膜科学与技术》2021年第1期116-122,共7页Membrane Science and Technology

基　　金：国家重点研发计划(2016YFF0204301);北京市科协金桥工程种子资金(ZZ19035)。

摘　　要：采用荷正电纳滤膜进行市政水体中低浓度氨氮(NH3-N主要以NH4^+形式存在)去除性能研究,从离子微观理化参数的角度探究了共存阴离子Cl^-和SO24^-以及共存阳离子Mg^2+和Na^+对荷正电纳滤膜分离NH4^+性能的影响.结果表明,由于Cl^-与SO4^2-的微观理化参数区别很大,Cl^-比SO4^2-更优先透过荷正电纳滤膜,为保持膜过滤产水为电中性,进料液中的低电荷、小水合半径、小平均离子势、大扩散系数的NH+4会比Mg^2+优先透过膜.如果进料液中没有Na^+,则会导致NH+4的低截留,反之,由于NH4^+和Na^+微观理化参数较为相近,均可以透过膜,则会导致NH+4的优先透过失效.不同体系下的多级循环实验证明,MgCl^2+NH4Cl体系和Na2SO4^+(NH4)2SO4体系,利用荷正电纳滤膜均难以实现NH4^+与Mg^2+、Na^+的完全分离.A positively charged nanofiltration membrane was used to study the removal performance of low-concentration ammonia nitrogen(NH4^+)in municipal water.The effects of co-existing anions Cl^-and SO4^2-as well as co-existing cations Mg^2+and Na^+on performance of NH+4 separation by positively charged nanofiltration membrane were investigated from the perspective of ionic microscopic physicochemical parameters.The results showed that Cl^-could preferentially permeated the positively charged nanofiltration membrane than SO4^2-,mainly due to the huge difference between the microscopic physicochemical parameters of Cl^-and SO4^2-,and then NH4^+with lower charge,smaller hydration radius,smaller average ion potential and larger diffusion coefficient in the feed liquid could preferentially permeate the membrane than Mg^2+in order to keep the water outlet side of the membrane electrically neutral.If there was no Na^+in the feed liquid,the rejection rate of NH4^+would be lower.Conversely,since the microscopic parameters of NH4^+and Na+were similar,both could permeate the membrane,leading to the failure of NH4^+preferential permeation.The multi-stage cycling experiments under different systems proved that it was difficult to achieve complete separation of NH4^+from Mg^2+and Na^+using positively charged nanofiltration membrane for MgCl2^+NH4Cl system and Na2SO4^+(NH4)2SO4 system.

关 键 词：荷正电纳滤膜 脱铵 共存离子 微观理化参数 截留率 

分 类 号：TQ028.8[化学工程] X703.1[环境科学与工程—环境工程]