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.

In recent years color removal from textile effluents on an industrial scale has received a lot of attention not only because of its potential toxicity but also because of its visibility issue. The current study investigated the use of Banana Peel (BP) as a low-cost adsorbent for Reactive Red 43 (RR43) and Malachite Green (MG) removal from aqueous solution. There are numerous color removal techniques, the most common of which is adsorption. The practical performance evaluation in a batch reactor is carried out due to its feasibility of operation. In our batch system, we looked at variables like initial dye concentration, contact time, adsorbent dose, and solution temperature. Thermodynamic, kinetic, and adsorption isotherm studies have all been evaluated. The adsorbent was characterized using different techniques. The equilibrium data was analyzed by Langmuir and Freundlich isotherm and showed a good fit with the Freundlich isotherm (R 2 =0.964 for RR43,0.996 for MG). kinetic data were analyzed using pseudo-first order and pseudo-second order kinetic, the adsorption kinetics data were fitted to pseudo-second order kinetic 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 optimized conditions were (2.15, 6.3) solution pH for RR43 and MG respectively,10mg/L initial dye concentration, adsorbent dose 0.1 gm/20 ml, and adsorption time 80 min,100 min for RR43 and MG respectively, and (92.82% and 82.52%) of RR43 and MG were removed by BP at experimental optimum conditions. The experimental results show that BP has good potential as a bio-sorbent to remove the colour from textile effluent and as an alternate low-cost adsorbent.