Desalting and recovering naphthalenesulfonic acid from wastewater with concentrated bivalent salt by nanofiltration process

• Published in: Journal of membrane science 2014-10, Vol.468, p.242-249
• Main Authors: Qin, Jiaxu, Dai, Xingguo, Zhou, Yong, Zhang, Lin, Chen, Huanlin, Gao, Congjie
• Format: Article
• Language: English
• Subjects: Applied sciences; Bivalent salt; Chemistry; Colloidal state and disperse state; Degradation; Exact sciences and technology; Exchange resins and membranes; Forms of application and semi-finished materials; Fouling; General and physical chemistry; Membranes; Nanofiltration; Nanofiltration membrane; Naphthalenesulfonic acid; Permeation; Polymer industry, paints, wood; Polymerization; Recovery; Rejection; Technology of polymers; Waste water; Wastewater
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2014.05.055

Naphthalenesulfonic acid effluents with concentrated bivalent salts cause serious environmental pollution and are regarded as recalcitrant pollutants for degradation. In this study, a piperazine–ethylenediamine (PIP–EDA) nanofiltration (NF) membrane with significantly different rejections for 1-naphthylamine-3,6,8-trisulfonic acid (T acid) and (NH4)2SO4 was designed to recover this kind of important intermediate compound for dyes from wastewater with concentrated bivalent salt. The membrane was fabricated by regulating the chain structure and membrane property of PIP NF membrane using linear EDA through interfacial polymerization. The optimized PIP–EDA NF membrane exhibited excellent rejection (>94%) for T acid and the rejection for (NH4)2SO4 is only 36%. NF experiment and characterization results indicated that the addition of a small amount of EDA can obviously improve the permeation flux and the difference between rejections for T acid and salt simultaneously. The effects of solute concentration and operation conditions on membrane performance were investigated to explore the feasibility of this NF process. The results demonstrated that the change in salt concentration had a much greater impact on membrane performance than the variation in T acid concentration. Operation pressure and pH of the feed solution also significantly affected the membrane performance. The rejections for T acid and salt showed opposite change laws in the membrane fouling experiment, likely because of their differences in mechanisms. This new NF process can be used for the effective recovery and reuse of naphthalenesulfonic acid from concentrated salt wastewater. [Display omitted] •T acid was recovered from effluent with concentrated bivalent salt by NF process.•We designed NF membrane by regulating chain structure and property of membrane.•EDA can improve both permeation flux and difference between rejections for solutes.•The membrane performance was affected significantly by operation condition.