Chromate Removal from Water Using Surfactant-Enhanced Crossflow Filtration

• Published in: Separation science and technology 1997-07, Vol.32 (11), p.1899-1920
• Main Authors: Keskinler, B., Danis, U., Çakici, A., Akay, G.
• Format: Article
• Language: English
• Subjects: Applied sciences; Chromate removal; Crossflow filtration; Exact sciences and technology; General purification processes; Pollution; Surfactant enhanced filtration; Surfactant removal; Wastewater treatment; Wastewaters; Water treatment and pollution
• ISSN: 0149-6395; 1520-5754
• DOI: 10.1080/01496399708000744

Removal of chromate from water was investigated using the surfactant enhanced crossflow filtration technique in which the cationic surfactant, cetyl trimethylammonium bromide (CTAB), was the carrier for the metal ions. The variation of chromate and surfactant rejections, and permeate flux with time were measured as a function of CTAB/chromate concentration ratio, while maintaining a constant transmembrane pressure drop, membrane pore size, and pH of the feed solution. The method was found to be effective in removing chromate from water. It was observed that the efficiency of chromate removal increased with increasing CTAB/ chromate ratio. It was also found that the chromate concentration had a significant effect on the CTAB concentration in the permeate and on the time taken to establish the secondary membrane which consists of a highly viscous surfactant phase in the hexagonal state in the absence of chromate. In the presence of chromate, permeate flux increased at the same CTAB concentration although the surfactant and chromate rejections decreased, indicating lowering of the secondary membrane resistance to permeate flow. These conclusions were confirmed by deadend filtration experiments which showed that the fouling index decreased by the addition of chromate while the opposite was valid when sodium chloride was present in the surfactant/water/electrolyte ternary system.