Comparative investigation of indigo blue dye removal efficiency of activated carbon and natural clay in adsorption/ultrafiltration system.

In the present study, indigo blue dye removal efficiency of activated carbon (AC) and natural clay (NC) was evaluated and compared, firstly in an adsorption unit, and then in an adsorption coupling ultrafiltration (A/UF) system. Effect of operating variables like pH, contact time, adsorbent dosage, initial dyes concentration during the adsorption was investigated and consequently optimised. The optimal conditions were employed for the adsorbents during the removal of the dye in the A/UF system. The optimal amount of NC and AC was 0.4 g/L and 0.3 g/L, respectively, and NC and AC displayed adsorption capacity of 57 mg/g and 53 mg/g, respectively, at this condition. Application of UF reveals a decrease of membrane fouling for both adsorbents in A/UF system. In addition, colour retention, when the adsorbents were used in A/UF, increased significantly from 90.5% to 99% as compared to using adsorption only. The efficiency of the membrane regeneration was estimated by the determination of the water permeability after rinsing. It is noteworthy to mention that a total regeneration of the membrane after the application of continous hybrid A/UF was achieved, however, the use of UF alone exhibited a fouling decrease by 40%. [ABSTRACT FROM AUTHOR]