Aqueous wastewater treatment with aluminum oxide, silica, and alginite

The adsorption of different types of dyes and stains over inorganic adsorbent materials such as silica, and aluminum oxide (basic and acidic) as well as over a mineral with an organic component, alginite, has been studied, with the idea of treatment of remnant dye solutions and solution wastes from small and educational laboratories. To recycle the adsorbents, they were heated to 600 °C where the adsorbates are combusted. The inorganic sorbents were compared to activated carbon derived from coffee grounds (ACCG) in their adsorption behavior. Acidic alumina was found to be an effective adsorbent material for azo dyes and anionic dyes/stains, but also for textile dyes, with very high adsorption capacity. The adsorption capacity of alginate and silica was found to be almost the same for cationic dyes, while the adsorption capacity of ACCG is the least.