The Adsorption Equilibrium and Kinetic Studies for The Removal of Crystal Violet Dye (Methyl Violet 6b) from Aqueous Solution Using Avocado Pear Seed Activated Carbon

In this study, adsorption equilibrium and kinetic studies for the removal of crystal violet (CV) from an aqueous solution were investigated using a batch adsorption process. The activated carbon was prepared by carbonizing the avocado pear seed at a carbonization temperature of 500OC for 1hr and was impregnated with a 30% concentration of aqueous HCl solution which was further activated in a muffle furnace at a temperature of 500OC for 1hr. The avocado pear seed activated Carbon obtained was characterized using proximate analysis, Fourier Transform Infra-Red Spectrophotometer (FT-IR) analysis and Scanning Electron Microscope (SEM) analysis. The effect of various adsorption parameters such as contact time (15-150 min), initial dye concentration (25-150 mg/L), adsorbent dosage (1-9 g), particle size and pH of dye solution were investigated. The adsorption equilibrium data were fitted into different isotherm models and the Langmuir model exhibited the best fit which implied that the adsorption of CV dyes onto avocado pear seed activated carbon was monolayer and the adsorbent surface was homogeneous and also; adsorption energy was uniform for all sites and there was no transmigration of adsorbate in the plane of the surface. The kinetic studies revealed that the adsorption data fitted well to the pseudo-second-order model with a high correlation coefficient of 0.977 when compared to other models, thus; signifying that the adsorption’s mechanism was chemisorption. APSAC shows a much better adsorption capacity for CV dye removal having a maximum adsorption capacity of 3.3254 mg/g and percentage removal of 99.995 %. Hence, APSAC can be used as an effective and low-cost adsorbent for the removal of CV dye from an aqueous solution.