Removal of Reactive Blue 49 (RB) Onto Untreated Peanut Shell (UPS) Waste-Kinetic Study, Modeling, Mechanism, and Regeneration of the Adsorbent

Pollution of water caused by different contaminants is a serious threat and a challenging problem. Various toxins are discharged into water bodies from several industries and other sources thus causing a large pollution. Because of their hazardous nature, excessive usage of textile dyes is a major environmental concern. Therefore, the aim of this study was to evaluate the adsorption of Reactive Blue 49 (RB), a recalcitrant dye onto untreated Peanut Schell (UPS) from aqueous solutions in a batch system. However, the effects of operational factors like initial pH (2-12), contact time (0-60 min), adsorbent dose (1-10 g/L), RB concentrations (10-40 mg/L), and temperature (298-318 K) were investigated on the adsorption efficiency of UPS. The latter was characterized by BET surface area (S-area = 30.05 m(2)/g), the point of zero charge (pH(pzc) = 6), FT-IR spectroscopy, and scanning electron microscopy (SEM). Batch studies were conducted to determine the optimal parameters required to reach the adsorption equilibrium. The maximum adsorption capacity of UPS for RB at 298 K was found to be (q(max) = 30.30 mg/g). The adsorption kinetic data were analyzed using the pseudo-first-order and pseudo-second-order models. It was established that the adsorption process obeys the pseudo-second-order kinetic model with a determination coefficient (R-2) equal to 0.999. The thermodynamics parameters such as the standard free energy & UDelta;G & DEG; (0.999, -4.45, and -9.82 kJ/mol), negative enthalpy & UDelta;H & DEG; (-172.2 kJ/mol), and change of entropy (-0.544 J/mol/K) indicated a spontaneous and exothermic physisorption.

Automated summary

Water pollution caused by various contaminants is a serious problem. This study aimed to evaluate the adsorption of Reactive Blue 49 onto untreated Peanut Shell. The effects of operational factors on the adsorption efficiency were investigated, and it was found that the maximum adsorption capacity of Peanut Shell for Reactive Blue 49 was 30.30 mg/g. The adsorption process followed the pseudo-second-order kinetic model and exhibited spontaneous and exothermic physisorption.