Immobilization of dye pollutants on composite adsorbent coating: Screening, efficiency and adsorption mechanism

A complete immobilization of the adsorbed contaminant at a surface of composite adsorbent coating has been a main scope of this research study. This approach has been investigated so that it can be easily handled and removed after adsorption process, unlike the filtration or centrifugation needed for powder or nano-adsorbents. Besides, the need for simultaneous active cationic and anionic sites required a strong electrostatic interaction and bonding, as well as high surface area. Basic mixtures of composite adsorbent coating composed of binder, fillers, surfactant and water as solvent. Screening study on an effective fillers were selected from clay based types (bentonite, sepiolite, kaolinite, diatomite and zeolite). Results showed that bentonite as a filler exhibited an excellent removal for both cationic and anionic dyes once mixed with binder and surfactant. Coating-based form proved high accessibility of adsorbate to the surface and internal sites of adsorbent by having higher percentage removal compared to powder-based form.