Multicomponent Sorption of Pyridine and Its Derivatives from Aqueous Solution onto Rice Husk Ash and Granular Activated Carbon

The present paper deals with the simultaneous removal of Pyridine (Py), $\alpha$ -picoline $\left(\alpha \text{Pi}\right)$ , and $\gamma$ -picoline $\left(\gamma \text{Pi}\right)$ from aqueous solutions by sorption onto rice husk ash (RHA) and granular activated carbon (GAC). Optimal design of experiments using Taguchi’s methodology has been applied to study the effects of various parameters, viz adsorbent dose, initial pH, contact time, initial concentrations, and temperature on the simultaneous removal of Py, $\alpha \text{Pi}$ , and $\gamma \text{Pi}$ . $3^{13}$ orthogonal array of Taguchi design has been used for parameter optimization for the sorption $\left(q_{\text{tot}}\right)$ of Py, $\alpha \text{Pi}$ and $\gamma \text{Pi}$ , by RHA and GAC. The ANOVA shows that the initial concentration of $\alpha \text{Pi}$ is the most significant parameter with 27.6% and 27.8% contribution to the $q_{\text{tot}}$ for raw and signal-to-noise (S/N) ratio data, respectively, for RHA. For GAC, the adsorbent dose $\left(m\right)$ is the most significant parameter with 32.2% and 17.5% contribution to the $q_{\text{tot}}$ for raw and S/N ratio data, respectively. The interactions between initial concentrations also contribute significantly to the overall sorption. Using the optimum conditions obtained by Taguchi’s experimental design, the respective percent removal of Py, $\alpha \text{Pi}$ , and $\gamma \text{Pi}$ was found to be $\sim 49$ %, $\sim 71$ %, and $\sim \mathrm{88\%}$ by RHA, and $\sim 42\%$ , $\sim 61\%$ , and $\sim 71\%$ by GAC. The spent RHA and GAC can be used as fuels in furnaces.