Application of response surface methodology in optimization of cadmium adsorption by raw rice husk

This study was aimed to model and optimize the adsorption process of cadmium from aqueous solution onto raw rice husk (RRH). The batch experiment was carried out in four factors as a function of pH (A: 5 - 9), adsorbent dosage (B: 2 - 8 g/100 ml), contact time (C: 60 - 240 minutes) and initial concentration of adsorbate (D: 70 - 110 mg/L) to response (percentage of cadmium removal). Response surface methodology (RSM) was used to analyzed and optimize the effect of four factors in cadmium adsorption. The result showed that RRH can successfully reduce cadmium from aqueous solution in removal percentage from 79.45% to 97.978%. Value of pH, dosage, contact time and initial concentration was noted significant statistically. RSM was undoubtedly used to optimize the adsorption process where the optimum condition achieved at pH 9, dosage 5 g/100 ml, contact time 240 minutes and initial cadmium concentration 90 mg/L.