DOI: https://doi.org/10.55373/mjchem.v26i5.387

Keywords: Azadirachta; isotherm; kinetic; neem; xanthate

Abstract

This research investigates the behaviour of a xanthate-modified neem leaf powder (XNL) in removing methylene blue (MB) from an aqueous solution. Different treatments will create different unique characteristics of adsorbent. At the same time, each specific treated adsorbent will behave differently with different adsorbates. XNL is proven as an efficient and low-cost adsorbent for removing methylene blue (MB) dye from an aqueous solution. Fourier Transform Infra-red (FTIR), Thermogravimetric (TGA), Energy Dispersive X-ray spectroscopy (EDX), and Brunauer–Emmett–Teller (BET) were used to investigate the properties of XNL. These characterisations suggest that XNL has a specific area of 6.02 m2 g-1. The influence of adsorption parameters such as adsorbent dosage, solution pH, contact time, and initial MB concentrations was studied, and it was found that the optimum condition for MB adsorption is at pH 6 with the adsorbent dosage of 0.02 g. The adsorption results were well described by pseudo-second-order (PSO) kinetic, and adsorption isotherm, followed by both Langmuir and Freundlich models. The maximum adsorption capacity (qmax) of XNL for MB dye was found to be 263.80 mg g-1 at 318 K. Thus; this work indicates that the XNL can be used as a promising adsorbent for MB dye from aqueous solution. The MB dye adsorption mechanism by XNL can be assigned to several types of interactions, such as electrostatic attractions, H-bonding interaction, and n-π interaction.