ADSORPTIVE REMOVAL OF CATIONIC TOXIC DYES FROM AQUEOUS SOLUTION: ADSORBENTS DEVELOPMENT AND PERFORMANCE INVESTIGATION

Co-effect of pore size and specific surface area of the two different kinds of synthetic adsorbents on the adsorptive performance/ removal against cationic toxic dyes i.e., methylene blue (MB) and crystal violet (CV) was observed. Two different kinds of synthetic adsorbents were prepared using waste coal fly-ash and bentonite mixed with paper fiber (AP) and enteromorpha powder (AE). The findings depicted that an equilibrium adsorptive capacity for AE and AP against MB were 167.0 and 157.0 mg/g, respectively. On the other hand, equilibrium adsorptive capacities of AE and AP against CV were 130.0 and 150.0 mg/g. respectively. The adsorptive performance of AP and AE against MB showed positive correlation with specific surface area which was 21,94 and 34,23 m(2)/g, respectively. In contrast, adsorptive performance of CV indicated positive correlation with pore size not with the specific surface area of the adsorbents, which were 4.28 and 1,52 nm, respectively. The findings hinted that the specific surface area controlled the adsorption capacity, if the contamination molecules could pass through the pores of adsorbents. In contrast, the pores size of the adsorbents governed the adsorption capacity, if contamination molecules could not reach the active/ vacant sites of the adsorbents. Overall, it can be assumed that the pore size has a promising effect on the removal efficiency of dye molecules by these adsorbents. Moreover, the adsorption kinetics of AP and AE against MB and CV hinted that the contaminant molecules diffused within adsorbents and played a significant role to control adsorptive rate.