Removal of Methylene Blue Dye from Aqueous Solution using Magnetite Impregnated Khat Stem Nanocellulose Composites

Abstract

The increased development of industrial, urban, and agricultural activities around the world is primarily responsible for the remove of different contaminants, including hazardous heavy metals, nutrients, dyes, etc., into aquatic environments. This study focused on the synthesis and characterization of nanocellulose derived from Khat stems, which was then impregnated with magnetite to form composite materials. The aim was to investigate the removal of methylene blue (MB) dye from aqueous solutions using these composite adsorbents. Magnetite impregnated nanocellulose composite (MNC) was synthesized by the coprecipitation method of nanocellulose with two iron oxides (FeCl2 and FeCl3) and characterized using phase transitions by Differential Scanning Calorimetry (DSC), crystallography by X-ray Diffraction (XRD), Functional groups by Fourier Transforms Infrared (FTIR), morphology by Scanning Electron Microscopy (SEM), and Surface area by Brunauer, Emmett and Teller (BET). The MNC was more thermally stable than nanocellulose. The XRD spectra of MNC exhibited peaks at 2θ 16.6° and 22.6° which are supposed to represent the typical cellulose I structure and at 2θ of 18.4°, 30.4°, 35.5°, 43.2°, 53.9°, 57.2°, 62.8°, and 74.2° indicating the structure of magnetite iron oxide nanoparticles. The BET multi point surface area, average pore size, and total pore volume of MNC were 511.74 m2/g, 0.619 nm, and 1.335 cc/g, respectively. Batch adsorption experiments were conducted to examine the influence of various parameters, including pH, contact time, adsorbent dose and initial dye concentration, on the sorption of MB dye. The maximum MB dye removal efficiency was 97%, which was achieved at a pH of 8, an initial MB dye concentration of 10 mg/L, an adsorbent dosage of 0.07 g/100mg/L, and a contact time of 80 minutes. The adsorption mechanisms were more closely aligned with Langmuir isotherm model than Freundlich model, demonstrating a maximum adsorption capacity of 102.35 mg/g and a R2 of 0.996. The kinetics of the adsorption process was well described by the pseudo second order kinetic model, which achieved a high R2 of 0.996. The reusability test was investigated using a single sample weighing 0.07 g/100mL for five cycles, and up to 88.97% of methylene blue was eliminated. It has been observed that magnetite impregnated khat stem based nanocellulose composites has great adsorption capabilities for removing MB dye from an aqueous solution