Removal of Nickel by Means of Micellar-Enhanced Ultrafiltration (MEUF) Using Two Anionic Surfactants

Abstract

Micellar-enhanced ultrafiltration (MEUF) is an effective separation technique for removing metal ions from aqueous environments. The critical micellar concentration (CMC) of two anionic surfactants, sodium dodecyl sulfate (SDS) and linear alkylbenzene sulfonate (LAS), was determined by means of conductometry. The effects of pH, conductivity, and surfactant concentration on the permeate flow, retention of surfactants and nickel by MEUF, was studied. Results showed that for surfactant concentrations beyond the CMC, Ni(II) retention with SDS was slightly higher than with LAS (S/M = 45: Ni(II) retention was 70% and 55% for SDS and LAS, respectively). LAS surfactant was always retained in higher quantities than SDS. An increase in conductivity produced large reduction in Ni(II) retention and slightly increased surfactant retention. pH values between 4 and 8 did not affect nickel retention but enhanced the SDS and LAS surfactant retentions.