High adsorption capacity for cationic dye removal and antibacterial properties of Sonochemically synthesized Ag₂WO₄ nanorods

Abstract

α-Ag₂WO₄ nanorods with an average diameter of 15 to 25 nm and a surface area of ca. 115.0 ± 0.2 m²/g have been synthesized by a facile sonochemical technique. These nanorods have been used for the adsorption of various cationic dyes (rhodamine B, methylene blue, and malachite green) from aqueous solution. The adsorption process is fast, and ca. 100 % adsorption of a 20 ppm mixture of all three dyes occurs within 10 min. The adsorption process was studied by varying different regulating parameters such as the solution pH and the initial dye and Ag₂WO₄ concentrations, and the results were analyzed with various isotherm and kinetic models. The mechanistic pathway for the selective adsorption of cationic dyes has been explained through zeta potential studies. Moreover, the thermal regeneration of the sorbent was possible by furnace heating at 250 °C, and the nanorods were efficient for multicyclic use. X-ray photoelectron spectroscopy (XPS) has been performed on the thermally regenerated samples to ascertain their surface purity. The Ag₂WO₄ nanorods have a bactericidal effect and are active against both Gram-negative and -positive bacterial strains of Escherichia coli and Bacillus subtilis, respectively. However, the efficiency is more pronounced for Gram-positive bacteria. Thus, these sonochemically synthesized Ag₂WO₄ nanorods have great potential for the treatment of dye industry effluents as a promising adsorbent for cationic dyes from aqueous solution and are also useful as an antibacterial agent.