| Effect of anions and cations on performance of NH4+ separation by positively charged nanofiltration membrane |
| Authors: Liu Manman , Mo Hengliang , Chen Yili , Wen Jianping , Li Shuoding , Chou Shuren , Yu Kaichang , Wu Wenhui , Meng Jiayi |
| Units: 1. Beijing Origin Water Membrane Technology Company Limited, Beijing, 101400; 2. Beijing Origin Water Technology Company Limited, Beijing, 102206 |
| KeyWords: positively charged nanofiltration membrane; ammonium removal; co-existing ions; microscopic physicochemical parameters; rejection rate |
| ClassificationCode:TQ028.8;X703.1 |
| year,volume(issue):pagination: 2021, 41(1):116-122 |
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Abstract: |
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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 SO42- as well as co-existing cations Mg2+ and Na+ on performance of NH4+ 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 SO42- , mainly due to the huge difference between the microscopic physicochemical parameters of Cl- and SO42-, and then NH4+ with lower charge, smaller hydration radius, smaller average ion potential and larger diffusion coefficient on the water inlet side of the membrane could preferentially permeate the membrane than Mg2+ in order to keep the water outlet side of the membrane electrically neutral. If there was no Na+ on the water inlet side of the membrane, the rejection rate of NH4+ would be negative. 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 Mg2+ and Na+ using positively charged nanofiltration membrane for MgCl2+NH4Cl system and Na2SO4+(NH4)2SO4 system. |
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Funds: |
| 北京市科协金桥工程种子资金(No.ZZ19035) |
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AuthorIntro: |
| 刘曼曼(1993-),女,湖北随州人,研发工程师,硕士,主要研究方向为脱铵原理及脱铵新技术,E-mail:1083289053@qq.com |
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Reference: |
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[1]Korzenowski C, Minhalma M, Bernardes A M, et al. Nanofiltration for the treatment of coke plant ammoniacal wastewaters [J]. Separation and purification technology, 2011, 76(3): 303-307. |
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