Abstract
Abstract In recent years, water pollution caused by industrial waste has been a major problem throughout the world. To remove harmful impurities from water, using methylene blue (MB) as a model compound, modified clays were used, as they are capable of adsorbing various substances on their surfaces. The modified clays were obtained by grafting dimethyl sulfoxide (DMSO) and triethanolamine (TEOA) in the space between the layers of Shymkent clay. DMSO was first added to the natural clay; TEOA was also added at a temperature of 180°C and then held at that temperature for 2 h. The resulting modified clays were dried at 60°C for 24 h and characterized by X-ray diffraction (XRD), surface area analysis (SAA), Fourier-transform infrared spectroscopy (FT-IR), elemental analysis, and thermogravimetric analysis (DTA and TGA). Natural and modified clays (0.25–2.5 g L –1 , pH=1–12, and 50°C) were used to adsorb MB from an aqueous solution at a concentration of 50 mg L –1 . Contact with the adsorbent was maintained for 8 h. As much as 95.9% of the MB was removed from the aqueous solution in as little time as 15 min. Adsorption conditions were optimized, and the clay modified with TEAO showed better results than the natural clay (85% for modified clay vs 40% for original clay, at a clay concentration of 0.5 g L –1 ); significant adsorption was obtained over a wide pH range (>85% from pH 1 to 12).