Removal of 2, 4 dichlorophenol from aqueous medium using chemically modified low-cost adsorbent: Kinetics, isotherm, thermodynamics and regeneration studies

Elimination of 2,4 D from water bodies is very much essential and possible using adsorption. Using commercial adsorbents, removal of 2,4 D can be efficient but requires high operating cost and hence this study focuses on feasibility of producing Activated Carbon (AC) from agricultural residue for removing the 2,4 D from aqueous solutions was analyzed. The adsorbent prepared using the chemical method with phosphoric acid at 1:2 ratio and activated at 500°C, washed and dried AC was characterized for understanding its properties. Batch adsorption analysis of 2, 4 D adsorption on AC was conducted to study the effects of initial 2, 4 D concentration (200 mg/L to 1000 mg/L), pH (2–12), contact time (0–360 min) and temperature (30–50°C). The adsorption efficacy of prepared AC on 2, 4 D was determined with the optimized adsorbing conditions. The equilibrium data were analyzed using different isotherm models (Langmuir, Freundlich, Temkin, and Dubinin Radushkevich) and kinetics models (Pseudo-first order, Pseudo-second order). Also, the adsorption mechanism was found using the intra-particle diffusion model. The activated carbon from the selected agricultural residue was shown to be an efficient adsorbent by removing 87.59% of 2, 4 D. The thermodynamic and regeneration studies were carried out to find the feasibility and reusability of adsorbent. From the results, it was confirmed that the system follows Langmuir isotherm, Pseudo-second order and the reaction is spontaneous and endothermic in nature. The maximum regeneration of adsorbent was obtained using NaOH among the other eluents.

Duke Scholars

Author Gayathri R. Devi Surgery, Surgical Sciences