The ternary NiO-CoO-MgO catalyst in three ratios 20:20:60, 25:25:50, and 30:30:40 for these component oxides respectively, were synthesized by co-precipitation method of their carbonates by addition of a precipitate agent in basic media, and then calcinated these carbonate to obtain of mixed oxides. The prepared catalysts were characterized by using Powder X-Ray Diffraction (PXRD), Fourier Infrared spectroscopy (FT-IR), and Atomic Force Microscopy techniques (AFM) were used for identification of the prepared catalysts. The result showed that the particle size of these catalyst ratios, were in the nano range and the smallest size was 25:25:50. The investigation of catalytic activity of prepared catalysts was done by photo decolorization of Celestine blue B dye from simulated industrial wastewaters in aqueous solution. The decolorization efficiency of dye reached 99.9% after irradiation time for 1 h. Study the effect of different reaction conditions such as the pH of the medium, the weight of semiconductor and temperature of mixture reaction were shown that the maximum degradation was observed in conditions at pH = 4, catalyst dosage = 0.08 g, and temperature = 303 K.

The increasing demand for drinkable water has speeded the expansion of groundwater use. Unfortunately, many geogenic contaminants like arsenic significantly decrease the quality of groundwater. Arsenic in water has harmed at least 0.3 billion people globally. Researchers used various types of treatment technologies to treat arsenic from synthetic wastewater, such as reverse osmoses, adsorption, and electrocoagulation. The electrocoagulation technique has gained popularity due to its increased removal efficiency compared to traditional treatments, low cost, and low sludge generation. This research aims to analyse arsenic treatment and examine the effect of technique variables on the removal performance to determine the best process variables for water purification. The outcome highlighted that arsenic removal improved with higher current densities needing less operating time. As a result, the removal effectiveness of arsenic from water using the electrocoagulation approach went from 88% to 96% in an alkaline environment, which is preferable. The best working settings for arsenic removal include a current density of 6 mA/m2 and a treating time of 30 minutes to reach 81% arsenic removal effectiveness. The best pH level for treating arsenic-contaminated water has been identified as 9.

In this work, we examined the photocatalytic activity of different composite ratios of doped co-oxide (Co3O4-Ni3O4/Al2O3) with carbon nanotubes (CNTs) toward Celestine blue dye (CBD). This work involves preparation of composite catalyst Co3O4-Ni3O4/Al2O3 doped with CNTs in different percent (2%, 4%, 6% and 8%) by using wet impregnation method. The prepared materials were characterized usingFourier transform infrared spectroscopy (FTIR), Atomic force microscope (AFM) and X-rays Diffraction technique(XRD). The photocatalytic activity of these materials were investigated by following photocatalytic removal of Celestine blue dyeat λ max= 542nm and dye concentration equal to 100 ppm in different irradiation times. The obtained results showed thatthe best percent of doping the co-catalyst with carbon nanotubes was 6%,which gives a high photocatalytic dye removal equal to 99%.