Removal of Red Ponceau ۴R by a Combined Process Coupling Adsorption and Photocatalysis

This investigation explores the elimination of Red Ponceau ۴R (RP۴R) dye through a synergistic method combining biosorption and photocatalysis. The study utilized fig as a botanical biosorbent within aqueous mediums to evaluate the influence of various factors such as contact duration, pH of the solution, dosage of biosorbent, temperature, and initial concentration of dye on the biosorption capacity. The study identified that the most effective biosorbent concentration was     ۱ g/L, with an optimal pH of ۱.۵. The biosorption capacity was found to increase when the concentration of RP۴R varied between ۱۵ and ۱۰۰ mg/L. Equilibrium was reached in ۵۰ minutes, and the adsorption dynamics were well-described by the Langmuir isotherm model, as indicated by a correlation coefficient (R²) of ۰.۹۹۷. The biosorption kinetics adhered to a pseudo-second-order model, achieving an R² of ۰.۹۹۹. Thermodynamic assessments indicated that the process was both spontaneous and absorbed heat. Following this, the residual concentration of RP۴R was subjected to photocatalytic degradation using a CuFe۲O۴/ZnO hetero-system under solar light. The CuFe۲O۴ spinel was fabricated via a co-precipitation technique. Mott-Schottky analysis (C²-V) revealed p-type conductivity with the conduction band situated at (+۱.۶۰ VSCE), which is beneath the potential of the O۲/O۲•- couple, suggesting that electrons could transform RP۴R into radical O۲•- with ZnO acting as the facilitator. The photocatalytic degradation reached its maximum with a ۳۰% concentration of CuFe۲O۴. This degradation process followed first-order kinetics, with a half-life of ۵۶ minutes, and achieved a conversion efficiency of ۶۴% at an initial concentration of ۱۰-۴ M.

کلیدواژه ها:

Biosorption ، hetero-system CuFe۲O۴/ZnO ، Photocatalysis ، Red Ponceau ۴R ، vegetable plant