Adsorption of Methylene Blue from Aqueous Solution Using Steam-Activated Carbon Produced from <i>Lantana camara</i> Stem

Abstract

This study investigated the adsorption of Methylene Blue (MB) present in wastewater onto the activated carbon produce from Lantana camara stem. The agricultural material ( Lantana camara stem) was carbonized at 300° C for 2 h, ground and steam-activated. The Steam-Activated Lantana camara (SALC) stem carbon was characterized using Scanning Electron Microscope (SEM) and Fourier Transform Infrared (FTIR) Spectrophotometry before and after adsorption. Batch model experiments were conducted at 20° C to study the effects of pH, agitation time, adsorbent dosage and initial concentration of methylene blue. The equilibrium adsorption isotherms and kinetics were investigated. The FTIR bands at 3500, 2500, 2196 and 1682 cm -1 were shifted to 3646.3, 3030, 2822, 1709.05 cm -1 after MB adsorption. Similarly, the Scanning Electron Microscopy (SEM) analysis showed that the average pore size on the activated carbon was 20 μm. The Methylene Blue (MB) uptake increased with the increase in pH. Similarly, the dye adsorption increased as contact time increased, and reached equilibrium at 60 minutes. The removal of the dye increased when the dosage was increased from 0.5 - 2.0 g · L -1 , at different dye concentrations (50 - 200 mg · L -1 ). The percentage removal decreased with increasing initial dye concentration for SALC. The adsorption isotherm data fitted well to the Freundlich isotherm (R 2 = 0.989) while the experimental data fitted very well to the pseudo-second-order kinetic model (R 2 = 0.99). This study suggests that adsorbent prepared from Lantana camara stem can be used effectively for the adsorption of methylene blue in wastewater.