Micellar enhanced ultrafiltration (MEUF) and activated carbon fibre (ACF) hybrid processes for chromate removal from wastewater Original Research Article

Chromate removal from aqueous solutions by micellar enhanced ultrafiltration (MEUF) at different operating parameters initial retentate pressure, initial permeate flux, initial chromate concentration, pH, and molar ratio of chromate to cetylpyridinium chloride (CPC) has been investigated. At the separate experiment for each parameter, with the increase of the initial permeate flux, initial retentate pressure, and molar ratio of chromate to CPC, the removal increased while the permeate flux declined. Considering higher chromate removal efficiency and higher permeate flux, operating initial permeate flux of 43.7 L/m2.h, chromate to CPC molar ratio of 1:5 and operating initial retentate pressure of 0.14 MPa were found to be the optimum parameters within the experimental conditions. The chromate removal efficiencies were 98.6% and 99.5% respectively for molar ratio of 1:5 and 1:10 with the corresponding average fluxes of 33.3 L/m2.h and 24.6 L/m2.h. The CPC removal efficiencies were only 60.7% and 76.2% respectively. The adsorption capacity of the activated carbon fibre (ACF) was 259 mg/g. With ACF cartridge CPC removal reached above 98%. The MEUF–ACF hybrid process has the removal efficiencies of 99.9% and 98.6% respectively for CPC and chromate with the corresponding effluent concentrations of 0.29 mg/L and 0.27 mg/L at the molar ratio of chromate to CPC of 1:5. Two ACF cartridge units in series have removed CPC efficiently from the wastewater.