Removal of chromium ions (VI) from underground water in the hybrid complexation-ultrafiltration process

Transport and separation properties of ultrafiltration membranes made from polyacrylonitrile have been characterized and their suitability for chromium ion (VI) removal from underground water by means of complexed hexadecylpyridine chloride has been evaluated. It has been found that membranes of a 17.5% polymer content retain 98% of the chromium complex (VI) while the remaining ions present in water pass to the permeate. Tests which aimed at determining the most favourable amount of a complexing substance in relation to the amount of chromium ions (VI) and the optimum pH of the solution for which a retention coefficient of the chromium complex (VI) was the highest have been conducted. The results obtained confirmed that the complexation-ultrafiltration system presents an effective method for chromium ion (VI) removal from abyssal water.