Coal fly ash coated with carbon hybrid nanocomposite for remediation of cadmium (II) and photocatalytic application of the spent adsorbent for reuse

In this study, coal fly ash coated with a carbon hybrid nanocomposite (CFA/C HNCPs) was synthesised using a hydrothermal method and applied for the adsorption of cadmium ions (Cd²⁺) from aqueous solution. The possibility of reusing the spent adsorbent (Cd²⁺ loaded adsorbent referred to CFA/C–Cd²⁺ HNCPs) for the photocatalytic degradation of methylene blue dye (MB) was also investigated. CFA/C HNCPs exhibited rapid adsorption of Cd²⁺ ions through a pseudo second order kinetics model whereas the data was well fitted by the Langmuir Isotherm model. In addition, the Cd²⁺ loaded spent adsorbent played an important role for the photocatalytic degradation of MB with a percentage degradation of 97.41%. Interestingly, this is a new approach for the reuse of Cd²⁺ adsorbed material for photocatalytic application, which has significant environmental impact for reduction of waste derived from conventional adsorption techniques.