Iron-modified composite adsorbent coating for azo dye removal and its regeneration by photo-Fenton process: Synthesis, characterization and adsorption mechanism interpretation.

Highlights • Dye adsorption followed by photo-Fenton degradation is promising for water treatment. • Iron-modified composite adsorbent coating is a novel material for water treatment. • Several dye adsorption-desorption cycles can be performed via photo-Fenton oxidation. Abstract Adsorption is an extensively used technique in wastewater treatment because this process is low cost, practical in operation and efficient. However, the regeneration of spent adsorbents is usually restricted by the strong interactions between the surface of adsorbents and adsorbates. Costs of water purification can be reduced significantly if the spent adsorbents can be regenerated and reused for several cycles. Hence, one alternative to face this issue is based on the formulation of adsorbent in a form of coating by improving its function so that it will be feasible to perform the regeneration. In this study, we have improved a coating formulation by modifying it with an iron salt to carry out the photo-Fenton process in the presence of H 2 O 2 and light assistance. Results showed that the adsorption of Acid Red 1 on an iron modified composite adsorbent coating was effective and able to achieve up to ten adsorption-regeneration cycles via photo-Fenton process. A statistical physics model was applied to understand the dye adsorption mechanism. This model was utilized to estimate the adsorption geometry of this dye and to calculate the adsorption capacities at different temperatures. This statistical physics model relied on an energetic consideration in order to describe the interaction between the dye molecule and iron-modified composite adsorbent coating surface. [ABSTRACT FROM AUTHOR]