Removal of Methylene Blue Dye from Aqueous Solution using Mango Seed Kernel–derived Activated Carbon

Abstract

Dyes removal by adsorption using modified activated carbon is by far the most common and effective method for wastewater contaminants removal. The aim of this study was to remove MB dye from aqueous solution using modified mango seed kernels as adsorbent. The lignocellulosic-based dried mango seed kernel modified with 50% H2SO4 and 40% H3PO4 was followed by heating in an electrical furnace at 500ºC for 2 hr for enhancement of MB adsorption from the aqueous solution. The surface characterization of raw MSK and MKAC before and after adsorption was carried out by proximate analysis, FTIR, XRD and SEM analysis. FTIR results showed different functional groups like aldehydes, ester, amide group and carboxylic acid were observed at different wave numbers. The batch adsorption studies were also carried out at optimum condition: adsorbent dose 0.2 g/L, initial MB concentration 10 mg/L, contact time 60 min, pH 8 and shaking speed 150 rpm . It was observed that the maximum adsorption efficiencies of the MKAC with 50% H2SO4 and 40% H3PO4 were found to be 91.5% and 89.3% at room temperature, respectively. UV-Vis spectrophotometer technique was used for the measurement of concentration of dye before and after adsorption of MB at maximum wave length (λmax) of 665 nm.. The linear form of Langmuir and Freundlich models were applied to represent adsorption isotherm. The calculated equilibrium data of MB fitted Langmuir isotherm models with maximum adsorption capacity (qmax) for 50% H2SO4 and 40% H3PO4 were 10 mg/g and 5.8 mg/g respectively. Pseudo second-order kinetic model was found to be well fitted to the data obtained from R2 value