Optimization of the preparation of Millettia thonningii seed pods activated carbon for use in the remediation of dye-contaminated aqueous solutions

Abstract

An increasing research interest in the use of waste-derived activated carbon in the remediation of contaminated water as a renewable alternative to commercial activated carbon has been noted. This research evaluates the optimization of the preparation of activated carbon from Millettia thonningii seed pods for application in the removal of synthetic dyes from aqueous solutions. The Box-Behnken experimental design, a subset of response surface methodology is employed in this research as it provides an economical strategy to optimize the process using a minimal number of experiments. The effect of preparation factors such as activation temperature, activation time and impregnation ratio on the preparation process was evaluated and these conditions optimized by maximizing the activated carbon yield and the adsorption efficiencies of two synthetic dyes, Basic Violet 3 and Basic Blue 9. The optimal conditions established were activation temperature of 400 °C, activation time of 30 min and impregnation ratio of 2.0. The activated carbon yield, Basic Violet 3 and Basic Blue 9 adsorption efficiencies approached 39.12%, 83.25% and 91.05% respectively under these optimal experimental conditions. The optimized activated carbon was characterized via physicochemical and proximate analysis, Fourier transform infrared spectroscopy and scanning electron microscopy. Millettia thonningii seed pods activated carbon produced at the optimum activation conditions possessed desirable properties such as low ash content, low moisture content and suitable bulk density. The activated carbon also holds great potential for application in the removal of hazardous synthetic dyes from wastewater. Keywords Activated carbon • Optimization • Desirability function • Box-Behnken design • Millettia thonningii Abbreviations RSM Response surface methodology BBD Box-Behnken design°C Degrees centigrade OFAT One factor at a time BV3 Basic Violet 3 BB9 Basic Blue 9 MTSP Millettia thonningii seed pods MTSPAC Millettia thonningii seed pods activated carbon ANOVA Analysis of variance FTIR Fourier transform infrared A Activation temperature B Activation time C Impregnation ratio Y 1 Activated carbon yield Y 2 Basic Violet 3 adsorption efficiency Y 3 Basic Blue 9 adsorption efficiency D Desirability function DF Degrees of freedom Adj SS Adjusted sum of squares Adj MSS Adjusted mean of sum of squares

Screening of factors that influence the preparation of Dialium guineense pods active carbon for use in methylene blue adsorption: a full factorial experimental design

“…The term was however retained in the model being a hierarchical one. Similar results have been reported by Jasper et al (2019). The magnitude of the coefficient A (concentration of activating agent) as seen from the model equation, and its F value were highest indicating that the concentration of the activating agent had the most significant effect on the dye adsorption capacity.…”

Enhancing the Decolorization of Methylene Blue Using a Low-Cost Super-Absorbent Aided by Response Surface Methodology

“…The chemical treatment of OPTAC altered its carboxylate group, which explains the disappearance of the peak at 1372 cm −1 for the spectrum of OPTAC, whereas the appearance of peaks at 1796.2 cm −1 (stretching vibration of C=O in –COOH), 1557.5 (cm −1 assignable to stretching vibration of C=C), and 953 cm −1 correspond to the stretching vibration of C–O, C–X, or C–C [ 43 ]. The OPTAC spectrum has fewer strong peaks due to the heating effect during the activation process, where the decomposition of lignin, cellulose, and hemicellulose took place [ 44 ].…”