In the current survey, the removal of dye from contaminated water was studied by photocatalytic degradation using TiO2 nanoparticles with respect to pH, TiO2 dosage, reaction time, temperature and initial dye concentration. TiO2 nanoparticles were investigated by XRD, FESEM and FT-IR.The RSM was chosen to study the composition effects of input independent factors and one dependent output response (removal efficiency). The P-value (2.2 × 10−16), F-value (1832), R2 (multiple R-squared: 0.9985, adjusted R-squared: 0.9972), and lack of fit (0.432) indicate that the reduced full second order model is highly significant for dye removal by TiO2 nanoparticles.The maximum percentage removal of dye, 90.2%, was achieved at optimum operating conditions including pH=6.5, TiO2 dose (1.2 g L-1), contact time (67.5 min), temperature ( ), and dye concentrations (55 mg L-1)), respectively.The maximum removal efficiency was calculated to be 100%, using regression coefficients derived from the model and the Solver “Add-ins”.The results indicated that the TiO2 photocatalyst was very proper for the removal dye from contaminated water, and it had good efficiency in eliminating textile dyes. Manuscript profile

Magnetically separable MgFe2O4 was synthesized and used in catalytical ozonation of 4-chlorophenol (4-CP). The prepared catalyst was characterized by X-Ray Diffraction (XRD), Field Emission Scanning Electronic Microscopy (FE-SEM), Transmission Electron Microscopy (TEM), Brunauer−Emmett−Teller (BET) and Vibrating-Sample Magnetometer (VSM). The optimum conditions for the highest efficacy of the catalytic ozonation process were found to be pH 7, catalyst dose 0.2 g/L, O3 concentration 1.67 mg/L.min, contact time of 30 min and 4-CP concentration 100 mg/L. At these optimal conditions, the efficiency of process was 93.5%. In addition, the results showed that the catalyst can significantly enhance the mineralization of 4-CP, and more than 70% 4-CP were mineralized in the presence of the catalyst, that is almost 2.5 times higher than ozonation alone. Moreover, the results revealed that the removal efficiency was not affected by solution pH and removal efficiency in the O3/MgFe2O4 process exceeded 90% over a wide pH range of 4–10. This study demonstrates that MgFe2O4 is a recyclable and efficient catalyst in the ozonation organic pollutants. Manuscript profile