Factorial design analysis of As(V) adsorption onto iron-aluminum binary oxide-doped clinoptilolite

Abstract

Arsenic adsorption onto an iron-aluminum binary oxide-doped clinoptilolite was studied by using response surface methodology. The Box-Behnken experimental design was used to estimate the effects of major process parameters, namely pH (3-7), temperature (25-65 degrees C), and initial arsenate (As(V)) concentration (0.5-9.5 mg L-1). The experimental data fitted to the empirical second-order model was found to be significant, as was evident from the model F-value of 341.23. The coefficient of determination value of second-order regression model was found to be 0.9977 (R-adj = 0.9948), indicating the accuracy and general availability of the model. The initial arsenic concentration of 9.4 mg L-1, pH of 6.0, and temperature f 62.4 degrees C were found to be optimum for maximum As(V) uptake. The results showed that adsorption capacity increased with increasing temperature, indicating the endothermic nature of the adsorption process.