Influence of Salt and Surfactant on Copper Removal by Xanthan Gum-g-Itaconic Acid/Bentonite Hydrogel Composite from Water Using Fractional Factorial Design

Abstract

A novel xanthan gum-g-itaconic acid/bentonite (XG-g-PIA/BET) hydrogel composite was synthesized using free radical polymerization in the presence of ammonium persulfate as initiator and N,N’-methylenebis(acrylamide) as crosslinker. The Fourier transform infrared spectroscopy spectra of XG-g-PIA/BET composite before and after adsorption gave strong evidence of the successful adsorbance of copper ions with COOH groups. Influence of the presence of three typical salts (NaCl, CaCl2, and FeCl3) and three types of surfactants including anionic (Brij 35), cationic (N-Cetyl-N,N,N-trimethyl ammonium bromide), anionic (sodium dodecyl sulfate), and their two-term interactions on copper ions adsorption capacity were investigated using 32 experiments with fractional factorial experimental design. The analysis of variance (ANOVA) showed that the fitted model had a significant p value (<0.0001), and except FeCl3, all other variables present in the aqueous solution increased the copper adsorption capacity. In addition, there was no significant two-term interaction between different variables.