Removal of phenol from aqueous solution by coupling alternating current with biosorption

Abstract

The present research was devoted to water decontamination through the valorization of cellulosic fibers for the preparation of performing biosorbent, with high pollutant-uptake capacity and low cost. Luffa cylindrica (L.C) and zinc oxide were chosen for the synthesis of hybrid materials by precipitation with and without alternating current (AC). AC was used as a new alternative able to accelerate the reaction kinetics and to enhance the biosorption speed. The potential to remove phenol, from aqueous solution by coupling biosorption and AC, was highlighted. Pure L.C and hybrid materials (L.C + 4% Zn²⁺) synthesized with and without AC were chosen for the biosorption tests. The effects of pH, initial concentration, frequency, and contact time were studied. The efficiency of the coupling process was evaluated according to the quality of the treated water before and after purification. Results have shown that the percentages of chemical oxygen demand (COD), total organic carbon (TOC), germination indexes, and phenol removals have increased when adopting the coupling process. The maximal uptakes of phenol reached 15.4, 28.07, and 28.9 mg g^-1 for a concentration of 30 mg L^-1 of phenol, respectively, for raw L.C, L.C + 4% Zn²⁺ + AC, and L.C + 4% Zn²⁺ at pH = 2. Quantitative and qualitative characterizations confirmed the efficiency of the synthesized hybrid materials compared with pure L.C. The fractal model of Brouers Sotolongo was chosen for the description of the random distribution of the active sites. The kinetic and isotherm data showed a good correlation with the experimental results.

Keywords: Alternating current; Brouers–Sotolongo; Hybrid material; Phenol; Zn2+.