Efficient Removal of Methyl Red from Aqueous Solutions Using Chemically Modified Bentonite Clays: A Study of Adsorption Dynamics

The extensive discharge of synthetic organic dyes from the textile and leather industries has become a major environmental concern due to their toxic, persistent, and non-biodegradable nature. Among these pollutants, methyl red dye poses significant risks to aquatic ecosystems and human health. The present study aims to evaluate the adsorption efficiency of cetyltrimethylammonium bromide (CTAB)-modified bentonite as a low-cost and effective adsorbent for the removal of methyl red from aqueous solutions. Bentonite powder was modified using 0.5 mol L<sup>-1</sup> CTAB to enhance its surface properties and adsorption capacity. Batch adsorption experiments were carried out at pH 7 with initial dye concentrations ranging from 10 to 30 ppm. The adsorption process was monitored using UV–Vis spectrophotometry at a wavelength of 360 nm. The experimental results demonstrated excellent adsorption performance, with removal efficiencies exceeding 98% across all studied concentrations. A maximum removal efficiency of 99.62% was achieved at an initial concentration of 30 ppm within 90 minutes of contact time. The superior adsorption behavior is attributed to the increased surface area, mesoporous structure, and improved surface functionality resulting from CTAB modification. Structural and functional characterization using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) confirmed successful modification of bentonite and the interaction between dye molecules and active surface sites. Overall, the findings indicate that CTAB-modified bentonite is a promising, economical, and environmentally friendly adsorbent for the efficient removal of organic dyes from wastewater, offering potential application in sustainable wastewater treatment processes.