Microcrystalline Cellulose Based Adsorbent Derived from Watermelon Rind for Dye Removal

Abstract

This study investigated the potential of watermelon rind derived microcrystalline cellulose (MCC) for the removal of methylene blue dye from aqueous solutions. The objectives were to evaluate the adsorption capabilities of watermelon rind derived MCC and assess the effect of process variables on its adsorption capacity. FTIR analysis was conducted to compare the absorption patterns of untreated watermelon rind and MCC. The absence of peaks at 1720, 1584, and 1242 cm^-1 in the MCC spectra confirmed the successful removal of lignin and hemicellulose from the sample. Thermogravimetric analysis showed that MCC exhibited an earlier onset of degradation compared to watermelon rind and reached its peak degradation rate at 215°C, as indicated in the DTG curve. The scanning electron microscopy analysis revealed that the MCC exhibited a rod-like shape with a diameter of less than 74 µm and a length of less than 737 µm. With an intermittent breakdown of the fibrillar structure into individualised fibrils, this unique morphology provides a larger surface area for adsorption, thus increasing the potential of MCC as a bio-adsorbent. The adsorption behaviour of MCC in aqueous solution was then investigated, specifically focusing on the impact of contact time and initial dye concentration on its adsorption capacity. The results demonstrated that the optimum dye removal efficiency of 86.32% was achieved when the methylene blue dye concentration was 1.5 mg/L. Furthermore, the dye removal efficiency rapidly increased from 67.34% to 80.73% as the contact time increased from 20 minutes to 60 minutes, after which the rate of increase slowed down significantly. These findings highlight the importance of optimising these variables to maximise the adsorption potential of MCC for efficiently removing contaminants. These findings contribute to the development of sustainable and cost-effective methods for particle removal in water treatment applications.