Fixed-bed column study for the removal of hexavalent chromium ions from aqueous solutions via pyrolysis of rice husk

The elimination of hexavalent chromium ions from laden aqueous solution using rice husk ash (RHA) as a biosorbent from rice husk (RH) was investigated based on different experimental parameters of the continual fixed-bed column system. Fourier transform infrared spectrometry and scanning electron microscopy (SEM) were used to characterize RHA and RH. The result of varied parameters such as bed height (2.5, 4.3 and 5.8 cm), influent flow rate (5, 10 and 15 mL/min) and initial hexavalent chromium concentrations (50, 100 and 150 mg/L) seemed to be researched. The exhaustion period elevated with an increasing in bed height but reduced with a decreasing of both flow rate and initial concentration. The Thomas, Yoon-Nelson, Adams-Bohart mathematical models were successfully utilized to the biosorption within different experimental parameters conditions to predict the breakthrough curves and to assess the model experimental parameters of the fixed-bed column, which are valuable for process design. Yoon-Nelson model was found suitable for describing the experimental data than Thomas and Adams-Bohart models. The performance of RHA column investigation states the value of the good biosorption capacity for elimination of hexavalent chromium from laden aqueous solution.