Agricultural By-Products as Green Chemistry in Elimination of Reactive Red 43 From Aqueous Media- Adsorption Properties, Kinetics and Thermodynamics Study

Document Type : Original Article

Authors

Department of Chemistry, Faculty of Science (Gils), Al-Azhar University (Girls),Yousef Abbas Str, P.O. Box:11754, Nasr City, Cairo, Egypt

Abstract

The aim of this study is to find an effective green waste (GW) natural material as an adsorbent for the removal of C.I. Reactive Red 43 (RR43) from an aqueous solution using batch experiments. Agricultural-by-products such as Peanut Shell (PS) and Corn Cobs (CC) have been used as (GW). Scanning electron microscopy (SEM) coupled with Energy Dispersive X-ray (EDX) and Fourier transform infrared spectrometer (FTIR) techniques were used to characterize the adsorbent before and after adsorption process. The influence of operating factors such as adsorbent dose, initial concentration of dye, contact time, pH solution and temperature were studied. The equilibrium data was analyzed by Langmuir and Freundlich isotherm models and showed a good fit with the Freundlich isotherm (R2=0.999). Batch kinetic data were analyzed using pseudo-first order and pseudo-second order kinetic models, the adsorption kinetics data were fitted to pseudo-second order kinetic model with a good agreement with the intra-particle diffusion model. The parameters of thermodynamic including enthalpy ΔH°, entropy ΔS° and free energy ΔG° demonstrated that the adsorption process was feasible, spontaneous, and exothermic in nature. The results clarified that a large percentage removal, and the optimized conditions were (7.6±0.2 and 4.3±0.2) solution pH for PS and CC respectively, 20mg/L initial dye concentration, adsorbent dose 0.1 gm/20 ml, and 90 min adsorption time. 80.46% and 86.76% of dyes were removed by PS and CC respectively at experimental optimum conditions. These agricultural by-products are renewable, biodegrade able, inexpensive, and easily accessible with little or no cost. Their application as adsorbents is in line with the current trend of green chemistry and green environmental policies.

Keywords

Main Subjects