The boosted activity of AgI/BiOI nanocatalyst: a RSM study towards Eriochrome Black T photodegradation.

Nowadays, critical environmental pollution needs some novel, simple, effective, and cost-effective catalysts with high efficiency in the visible region of the light. Thus, the AgI/BiOI coupled nanocatalyst sample (CS) was prepared and briefly characterized. The pH pzc values of 6.2, 5.4, and 4.5 were estimated for AgI, BiOI, and AgI/BiOI samples. Based on the PXRD results, average crystallite sizes of 35.2, 34.7, and 34.1 nm were obtained for AgI, BiOI, and AgI/BiOI samples from the Scherrer formula and 38.3, 25.6, and 25.6 nm by the Williamson-Hall formula. SEM image confirmed a sheet-like BiOI morphology covered by AgI nanoparticles. The simultaneous interactions of the influencing variables on the boosted photocatalytic activity of CS sample towards Eriochrome Black T (EBT) were evaluated by response surface methodology (RSM) (under 100-W tungsten lamp irradiation with 230 mW/m 2 .nm irradiance). The goodness of the model was confirmed by the significance of the model (F value of 65.68 > F 0.05, 14, 13  = 2.55) and a non-significant LOF (F value of 0.97 < F 0.05, 10, 3  = 8.79) at a 95% confidence interval obtained in ANOVA analysis of the results. The center point runs have the following conditions: catalyst dose: 0.68 g/L; pH: 7.5; C EBT : 7.25 mg/L; and irradiation time: 53.5 min, while the optimal run included the following conditions: catalyst dose: 1.0 g/L; pH: 4; C EBT : 10 mg/L; and irradiation time: 80 min. About 95% of EBT molecules were degraded in the optimal conditions.