Effect of NaOH Concentration in Alkaline Treatment Process for Producing Nano Crystal Cellulose-Based Biosorbent for Methylene Blue

Abstract

The development of textile industry in Indonesia has been increasing rapidly. The vast and continuous development of the textile industry results in an evitable increase of wastewater. One of the wastewater ingredients that difficult to be treated is dye. Dye is a pollutant with complex aromatic structure that is difficult to degrade. There are many dyes could be used, however, methylene blue is mostly used. To treat MB, several treatment methods are available. Among the methods, adsorption has been widely applied, due to its simplicity and effectiveness. In this research, nano crystal cellulose (NCC), which has a large surface area dan better mechanical properties, was prepared from the oil palm trunk and it was proposed to adsorb the methylene blue. Briefly, the process of making NCC as a biosorbent consists of the raw material pretreatment, alkaline treatment, bleaching, hydrolysis, and sonication steps. Alkaline treatment plays an important role for extracting hemicellulose, lignin and other extractive substances, so that NCC is expected to have high cellulose purity. The alkaline treatment was conducted by extraction methode using NaOH at 80 °C for 2 hours. The result showed that the percent of removal of hemicellulose dan lignin were 50.0, 55.6, and 51.73 % for NaOH concentration of 3, 4, and 5 % (w/v) respectively. This result was also supported by the result of FTIR spectra analysis on each corresponding sample. Based on these data, it can be confirmed that the optimum NaOH concentration for alkaline treatment of oil palm trunk is 4 % (w/v). Furthermore, adsorption test of NCC using methylene blue solution gave percent removal of methylene blue in the range of 69.46-72.51%.