Removal methylene blue from aqueous solution using silica aerogel prepared from bagasse ash

Abstract

One important component in the manufacturing industry is coloring substance. Methylene blue (MB) is one of the coloring substances commonly use industry. The frequent use of the substance may result in the accumulation of methylene blue in the environment and thus creates an environmental waste that is dangerous for living. To control the condition of the environment, efforts to minimize the accumulation of methylene blue with the least possible negative effect in the manufacturing industries need to be made. Synthesized silica aerogel, the bagasse-ash-based solid, originated from sugar factory can be a simple and cheap solution to the problem. This study is intended to discuss the use of silica aerogel as an adsorbent of methylene blue. The influence of experimental factors such as contact time, initial MB concentration, and the temperature was investigated. The adsorption equilibrium was represented with Langmuir and Freundlich isotherm models. Langmuir equations were found to have the correlation coefficient value in good (R2 = 0.9998). Adsorption of MB onto silica aerogel followed pseudo second order kinetics. The thermodynamic parameters such as the change in free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) were determined and the negative values of ΔG° indicated that the process of removal was spontaneous at all values of temperatures. The adsorption process was spontaneous and exothermic nature.