Optimization and modeling of process variables for adsorption of Basic Blue 41 on NaOH-modified rice husk using response surface methodology

The aim of this study was to optimize the conditions of the Basic Blue 41 (BB41) adsorption on NaOH-modified rice husk (NaOH-RH) using response surface methodology based on Box-Behnken design. The three-level factors considered were pH (4, 7, and 10), initial concentration of BB41 (50, 75, and 100mgL(-1)), and adsorbent dose (0.025, 0.0875, and 0.15gL(-1)). Statistical analysis of result has shown that the predicted values for BB41 adsorption were close to the experimental values and were in a good agreement, on the other hand, the F-value (40.48), p-value (0.0004), and R-2 (0.9865) indicated that the regression is able to give a good prediction of response for the adsorption process in the range studied. According to the results, when the response was set in maximize and all the three factors were set in a range, the optimized values for BB41 adsorption were predicted as follows: pH value of 8.47, and BB41 initial concentration of 67.9mgL(-1) and adsorbent dose of 0.12gL(-1) for removal efficiency of 97.65%.