Pretreatment of membrane separation of glyphosate mother liquor using a precipitation method

• Published in: Desalination 2013-03, Vol.313, p.140-144
• Main Authors: Liu, Zhiying, Zhu, Mingxin, Yu, Peng, Xu, Yanhua, Zhao, Xianguang
• Format: Article
• Language: English
• Subjects: Applied sciences; Attenuation; Chemical engineering; desalination; Exact sciences and technology; Flux; fouling; glyphosate; Glyphosate mother liquor; HPO32; Membrane flux; Membrane separation; Membrane separation (reverse osmosis, dialysis...); Membranes; mixing; Nanofiltration; Pollution; Precipitation; Precipitation method; Separation; Stirring
• ISSN: 0011-9164; 1873-4464
• DOI: 10.1016/j.desal.2012.12.011

During the nanofiltration membrane separation of glyphosate mother liquor, a precipitation method was employed to remove HPO32−, which is often the cause of membrane fouling and blockage. Such removal reduces the speed of membrane flux attenuation. The purpose of the present study was to investigate the effects of precipitant quantity and type, pH value, stirring time and speed, and standing time, on the removal of HPO32−. In addition, the membrane flux separated by the nanofiltration membrane of the mother liquor post-pretreatment, was tested. Results indicated that when the initial pH was 9, the following pretreatment procedure resulted in the removal of more than 60% of the HPO32− from the glyphosate mother liquor: the addition of 0.24mol/L AlCl3·6H2O, stirring at 300r/min for 30s and 100r/min for 2.5min, followed by standing for 30min. This pretreatment–precipitation method can markedly enhance the nanofiltration membrane flux in the mother liquor and reduce the membrane flux attenuation, which facilitates nanofiltration membrane separation of the glyphosate mother liquor. ► HPO32− is removed effectively by the pretreatment–precipitation method. ► The precipitation can markedly enhance the nanofiltration membrane flux. ► It facilitates nanofiltration membrane separation of the liquor by precipitation.