M. A. Zarami1, A. L Yaumi1, M. M. Aji1*, S. Kiman1, H. Umar1 and B. Tijjani2
1Department of Chemical Engineering, University of Maiduguri, Borno State, Nigeria
2Department of Chemical Engineering, Federal University of Technology Owerri, Imo State
*Corresponding author’s Email: moduajim@unimaid.edu.ng, doi.org/10.55639/607.02010007
ABSTRACT
This study developed a composite material from Neem Leaves (NL) and Moringa Seed Husk (MSH) for the adsorption of Methylene Blue (MB) dye effluent. The MSH and NL were pyrolyzed at 400°C to synthesize MSH and NL biochar. The biochar was further treated with sodium hydroxide (NaOH) and potassium hydroxide (KOH) as activating agents, separately. The precursors were characterized using Fourier Transform Infrared (FTIR) analysis, Energy Dispersive X-ray Spectroscopy (EDS), and Scanning Electron Microscopy (SEM). SEM analysis revealed transformations in the surface morphology of the material. EDS analysis showed variations in the elemental composition of the materials before and after adsorption of MB dye. FTIR analysis identified the functional groups involved in MB dye removal. Response Surface Methodology (RSM) was performed to determine the optimum operating conditions and to optimize the adsorption capacity. Factors affecting adsorption, including pH, contact time, temperature, concentration, and dosage, were investigated. The produced activated carbon was tested to determine its adsorptive capacity and efficiency using MB dye.It was observed that KOH-impregnated activated carbon exhibited better results than NaOH. KOH, as an activating agent, produced a more porous structure with a higher surface area and better-developed surface functional groups compared to NaOH. This enhanced both physical adsorption and chemical interactions, making KOH-activated carbon more effective in adsorbing MB dye. The surface of KOH-activated carbon was found to be more hydrophilic, facilitating the adsorption of MB from aqueous solutions. Hydrophilic surfaces tend to interact better with aqueous environments, improving the accessibility of the dye to adsorption sites. The best results were achieved at an MB concentration of 400 mg/L, using 0.7 g of residue at a stirring rate of 250 rpm for one hour, with an adsorption efficiency of up to 95%. The adsorption equilibrium and kinetics of MB dye on the activated carbon were examined at 30°C. Adsorption isotherms were determined and correlated with common isotherm equations. The equilibrium data for MB adsorption fit well with the Langmuir model, indicating monolayer coverage of the adsorbate over a homogeneous adsorbent surface. Kinetic studies showed that the adsorption of MB onto NL and MSH-activated carbon fit the pseudo-second-order model, implying that the rate-limiting step is chemisorption.
Keywords:
Neem Leave,
Moringa Seed Husk,
Methylene Blue,
Adsorption