Study of Glutamate-Modified Cellulose Beads for Cr(III) Adsorption by Response Surface Methodology

Abstract

A cellulose-based adsorbent was prepared from a cellulose–ionic liquid solution by emulsification followed by modification with glutamic acid for Cr(III) adsorption from aqueous solution. Response surface methodology (RSM) coupled with central composite design (CCD) was employed to optimize the adsorption process to ensure high adsorption efficiency. Three independent variables [initial Cr(III) concentration, pH, and adsorbent dose] were coded as x1, x2, and x3 at five levels (−1.68179, −1, 0, 1, −1.68179), and a second-order polynomial regression equation was then derived to predict the responses. The standardized effects of the independent variables and their interactions were tested by preparing a Pareto chart. Analysis of variance (ANOVA) showed that a high coefficient of determination value (R2 = 0.9959) and a satisfactory predicted second-order regression model were achieved in the study. Therefore, the optimum conditions for Cr(III) adsorption were established, and the optimum values of the selecte...