Low-cost chemically treated sugarcane bagasse for removal of cationic, anionic and neutral dyes from aqueous solution

This study presents use of low-cost chemically treated sugarcane bagasse for the adsorption of three dyes: cationic (methylene blue-MB), anionic (Methyl orange-MO) and neutral (Neutral red - NR) dyes. The prepared sugarcane bagasse was characterised using a scanning electron microscope (morphology) and Fourier transform infrared techniques. The FTIR spectra revealed that all the bands were identified in the sugarcane bagasse due to cellulose, pectin and lignin presence. The effect of adsorbent dose, contact time, pH and concentration on the adsorption performance of sugarcane bagasse for the removal of MB, MO and NR dyes was studied. Kinetic and isotherm studies were also carried out to study the adsorption process further. The maximum adsorptive removal efficiency of MB, MO and NR dyes was found to be 98.2%, 50.3% and 81.2%, respectively, at the optimised condition of adsorbent dose: 8 g/L, time: 120 min, pH: 10 and concentration: 50 ppm. From adsorption kinetics, it was established that the adsorption process followed pseudo-second-order rather than pseudo-first-order. The correlation coefficient values for the PFO and PSO models were 0.9319 and 0.9994, respectively, for MB dye adsorption on SCB. The adsorption isotherm study established that the adsorption process followed the Langmuir model rather than the Freundlich model.