Preparation of clay/alumina and clay/alumina/Ag nanoparticle composites for chemical and bacterial treatment of waste water

•The clay/Alum and clay/Alum/Ag composites have been synthesized for the first time.•Both composites have high adsorption capacity of anionic and cationic dyes.•The synthesized composites can remove dye pollutants from aqueous solution quickly.•The clay/Alum/Ag nanocomposite exhibits very good antibacterial activity. The pollution of water resources with chemical and biological pollutants is the serious problem of the present century. So synthesis of new adsorbents which can remove both types of pollutants is necessary. In the present study a novel clay/mesoporous alumina composite has been synthesized in order to remove both cationic and anionic dye pollutants and their binary mixtures from aqueous solutions. Also the clay/mesoporous alumina/Ag nanoparticle composite has been synthesized for the first time by the new combined method and used for both chemical and biological treatment of aqueous solution. The characterization of the prepared nanocomposite has been performed by TEM and EDS techniques. The results show that the synthesized materials are good adsorbents for effective removal of both cationic and anionic dye pollutants. Also the nanocomposite shows very good antibacterial activity against both Gram negative and Gram positive bacteria.