Green synthesis of AC/ZnO nanocomposites for adsorptive removal of organic dyes from aqueous solution

Abstract

In the current study, a facile and green route for synthesis zinc oxide supported activated carbon nanocomposites (AC/ZnO) using Pontederia crassipes leaves has been conducted. The synthesized ZnO/AC nanocomposites have been obtained as adsorbents to remove Malachite Green (MG) and Congo Red (CR) dyes after characterization via XRD, FTIR, FE-SEM, EDX, BET-BJH, TEM and Raman spectroscopy techniques. The influence of five parameters such as time, adsorbent dosage, solution pH, dye concentration and temperature has been optimized as batch experiments. The results showed that the ZnO/AC (10 %) nanocomposite showed the better removal efficiency of 98.87 % for CR and 99.23 % for MG with an estimated maximum adsorption capacity of 987.77 mg/g for CR and 74.36 mg/g for MG. The Freundlich, Halsey isotherms (R2 = 0.9969 for CR and 0.9842 for MG) and pseudo-second-order (R2 = 0.9996 for CR and = 0.9997 for MG) models were most appropriate in the description of the adsorption process. These findings confirmed that ZnO/AC fabricated via green approach is an efficient adsorbent for the removal of cationic and anionic dyes and could possibly be used for the treatment of other industrial textile effluents.