Sorption Kinects and Equilibrium for The Removal of Cadmium and Lead from Aqueous Phase on Rice Husk in Inverse Fluidization Technique

Abstract

The objectives of this study are to use the inverse fluidization technique to remove heavy metals from wastewater using inexpensive agricultural waste (Rice Husks) and to investigate the effects of operating factors on the dynamic behavior of the adsorption procedure in the inverse fluidized bed, such as the mass of modified rice husks, flow rate (Q), and particle size (dp ). During batch experiments, the best metal ion removal effectiveness was found to be at pH 5, which was discovered after investigating several pH values to achieve this goal. The ideal shaking speed for batch adsorption was 180 rpm. Adsorption efficiency was seen to rise as contact time in the process increased, and the ideal contact time was 3 hours. According to the findings, Cd and Pb had high removal efficiencies from aqueous solutions, 96.83 percent and 91.90%, respectively. Continuous column experiments (inverse fluidized bed) were used to confirm the adsorbent loading capacities for cadmium and lead, which were evaluated by batch research. The proposed adsorbent’s highest adsorption capacity in a batch system was determined to be 7.38 mg/g for Cd and 6.93 mg/g for Pb. Three models-Temkin, Freundlich, and Langmuir-were fitted to a series of equilibrium isothermal tests. The Freundlich isotherm model, with correlation coefficients R2 of 0.98 for Pb and 0.97 for Cd, offered the best fit to the experimental data for this system. The rice husk equilibrium isotherms were determined to be of a favorite kind. To investigate the impact of initial concentrations, bed depth, flow rate, and particle size at a temperature of 30 on the effectiveness of the adsorption process, numerous experiments were conducted in an inverse fluidized bed column. According to the results, rice husk appears to be a material that shows promise for cleaning wastewater of contaminants and toxins.