Performance of Chitosan Beads after treatment with spent coffee grounds for the adsorption of methylene blue

Abstract

Spent coffee grounds are one of the ingredients that are abundantly available today and can be used as a crosslinking material with other materials. The objective of this work was chitosan (CS) beads and treatment spent coffee grounds (TCG) made into beads to determine their ability to adsorb methylene blue (MB). The ratios of CS to TCG (by weight) were varied to make beads with the following composition: 1:0 (CS), 1:1 (CS/TCG 3%), 1:2 (CS/TCG 6%), and 1:3 (CS/TCG 9%). Glutaraldehyde crosslinking was performed to increase the stability of the beads in water; these beads were used to test the capacity to adsorb MB. The beads of different compositions were assessed using several techniques, including scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) and ultraviolet-visible spectroscopy (UV-Vis). The results of the morphological analysis showed that adding TCG resulted in the formation of more pores and cavities in each sample. It enhances its effectiveness as an adsorbent. Analysis of the composition of TCG via XRF showed the presence of a carbon atom, a precursor of activated carbon. The FTIR spectrum indicated that functional groups played a crucial role in adsorption. The UV-Vis results showed that the degradation percentage increased with an increase in the weight ratio of CS/TCG beads. The CS beads treated with TCG could be used to adsorb MB for up to seven repetitions, with an adsorption percentage of 87.8%.Therefore, it is concluded that the measured CS/TCG data were numerically fitted using Langmuir and Freundlich models to analyze the adsorption isotherm behavior.