The photocatalytic oxidation of methylene blue (MB) in aqueous media is explored using nanoscale ZnO nanoparticles (ZnO NPs) for maximal dye removal within the high-surface-area nanoparticle photocatalyst. The operating parameters such as illumination time, initial MB load, ZnO NP dose, solution flow rate and pH were examined. The experimental results revealed the alkaline pH (12.0) corresponding to the higher oxidation rate within only 20 min of reaction time; however, increasing the initial MB load decreased the reaction rate at the optimum circulation flow rate of 460 mL/min and ZnO NP dose of 0.4 g. Additionally, for providing maximum performance, the interaction between the most effective independent parameters (ZnO NP dose, flow rate, and initial pH) were explored using Box-Behnken experimental design based on the response surface methodology. The results showed a good fitness of the model (R 2 = 96.86%) with the experimental data. The optimum values were recorded after 20 min of reaction time with the values: 0.45 g/L for ZnO NP dose, 370 mL/min for flow rate and pH 11, showing a 94% maximum dye removal compared to 92% using manual optimization. Finally, the kinetic models were applied and the data were described by second-order kinetic model.

The present study is set out to determine the photocatalytic degradation potential of ZnO nanoparticles for effective degradation of Eosin dye. The heterogeneous photocatalytic experiments were carried out by irradiating aqueous dye solutions with ultraviolet light. The influence of effective parameters like flow rate, pH, catalyst dose, and dye concentration was examined. The best degradation efficiency (66.82%) of ZnO Nanoparticles against Eosin dye was achieved within 90 min of reaction time. The Box–Behnken design under the Response Surface Methodology (RSM) was chosen as a statistical tool to obtain the correlation of influential parameters. The optimum values were recorded as follows: 0.59 g, 15.75 ppm and 136.12 ml/min for amount of catalyst, dye concentration and flow rate, respectively. The maximum percent degradation achieved at these conditions was 71.44%.

A conditioning treatment is performed on alum sludge for the object of enhancing its filterability, thus enhancing water removal from sludge. The sludge used in the experiments is obtained from Kedwan plant, Minia city, Egypt. Conditioners of different types are used, e.g., ferric chloride and lime (as an example of inorganic chemicals), Fenton reagent (adopted as one of the advanced oxidation processes) and Chitosan (adopted as a type of biopolymers). The parameters studied are: effect of: conditioner dose, rate of mixing, time of reaction and pH value. The results of experiments showed that the minimum values for SRF (target of experiment) are 4.

The present study is set out to determine the photocatalytic degradation potential of ZnO nanoparticles for effective degradation of Eosin dye. The heterogeneous photocatalytic experiments were carried out by irradiating aqueous dye solutions with ultraviolet light. The influence of effective parameters like flow rate, pH, catalyst dose, and dye concentration was examined. The best degradation efficiency (66.82%) of ZnO Nanoparticles against Eosin dye was achieved within 90 min of reaction time. The Box–Behnken design under the Response Surface Methodology (RSM) was chosen as a statistical tool to obtain the correlation of influential parameters. The optimum values were recorded as follows: 0.59 g, 15.75 ppm and 136.12 ml/min for amount of catalyst, dye concentration and flow rate, respectively. The maximum percent degradation achieved at these conditions was 71.44%.