Cationic hydrophilic polymers coupled to ultrafiltration membranes to remove chromium (VI) from aqueous solution Original Research Article

The removal of chromate anions is analyzed by liquid-phase polymer based retention (LPR) technique using both washing and enrichment methods with cationic hydrophilic polymers containing quaternary ammonium salts and different counterions. Using the washing method, the Cr(VI) removal experiments were performed at different pH with P(ClAPTA), P(ClVBTA) and P(SAETA) as extracting agents. The results showed highest retention capacity of Cr(VI) for all polymers at pH 9. The retention capacity is maximum for polymers with chloride counterions. The optimum molar ratio of polymer: Cr(VI) for efficient chromium separation was 10:1 to reach the maximum chromium (VI) removal. The enrichment method shows the maximum retention capacity (mg Cr(VI)/g polymer) of 164 for P(ClVBTA), 152 for P(ClAPTA), and 90 for P(SAETA). The FT-IR spectra of P(ClVBTA) and P(ClVBTA)–Cr(VI) were compared before and after maximum retention capacity, showing differences due to the presence of Cr(VI).