Abstract
The adsorption results of Cr(VI) removal from aqueous solutions on Litchi chinensis have been optimized by the Box-Behnken design of response surface methodology. Three experimental parameters (dose, temperature, and pH) were chosen as independent variables. The maximum Cr(VI) adsorption was obtained at the initial pH of 2. Analysis of variance (ANOVA) of the results was successfully used to check the significance of the independent variables and their interactions. The three-dimensional (3D) response surface plots were used to study the interactive effects of the independent variables on % Cr(VI) removal. These figures successfully interpret the effect of interaction between pH (0.1-1.0), adsorbent dose (0.1-1.0 g.) and temperature (0-50 A degrees C). The second-order polynomial equation was generated for the response. A statistical hypothesis test was conducted to critically analyze the experimental data by applying t test, paired t test, and Chi-square test. The comparison of t-calculated and t-tabulated values showed that the results were in favour of the conducted experiment.