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Heterogeneous photocatalysis is an increasingly popular method used to decontaminate polluted water. Dyes have become one of the major sources of water pollution and methyl orange is one of the most commonly used dyes in the textile industries. The objective of this study was to remove MO and compare the efficiency of the synthesized photocatalysts. In the current work, photodegradation of methyl orange dye, selected as a pollutant model is carried out at room temperature in aqueous solution of Zn-doped TiO2. The photocatalysts tested in this study were prepared by coprecipitation method. The catalysts were characterized by XRD, TEM, SEM, EDS, and DRS, before proceeding to photodegradation. X-ray diffraction showed that samples are only composed of TiO2anatase, except TiO2P25, which contains some crystallites in the rutile form. According to TEM, all nanoparticles of the different photocatalysts have a spherical, clearly dispersed and fine morphology. A strong agglomeration is observed for TiO2P25. Energy dispersive X-ray spectroscopy confirmed Zn doping by the presence of peaks attributed to zinc. The UV–Vis diffuse reflectance spectroscopy (UV–Vis DRS) shows a shift of absorption from the UV region to the visible light region and shows that all nanoparticles have very similar absorption thresholds, thus the doped catalysts are promising materials for the use of visible light. The obtained results during the study of the adsorption showed that the order of adsorbability varies in the following decreasing direction: TiO2Sachtopore (ZnCl2/TiO2= 0.2%) > TiO2Sachtopore (ZnCl2/TiO2= 0.1%) > pure TiO2Sachtopore > TiO2P25. The photodegradation kinetics was studied as a function of several parameters. A comparison of the degradation kinetics of methyl orange has shown that TiO2P25 provides comparable performances to doped TiO2Sachtopore at 0.2% of Zn. 1 g/L is the optimum concentration for all catalysts used. The synthesized nanomaterials showed good photodegradation ability in MO decomposition, as well as the results reveal that photocatalysis is a very suitable technique for the purification of water containing methyl orange.

In order to optimize the water purification and treatment of polluted water, a new degradation technique of the organic matter called “heterogeneous photocatalysis” has been highlighted. Titanium dioxide TiO2semiconductor doped with Ni has been chosen as photocatalyst, which has been prepared by coprecipitation. The characterization of synthesized catalysts has been carried out using transmission electron microscopy, X-ray diffraction and diffuse reflectance spectroscopy and scanning electron microscopy as well as EDS. The obtained adsorption results showed that the dye adsorbs better on doped TiO2nanoparticles rather than pure TiO2. The kinetics of photodegradation was studied as a function of several parameters, such as the concentration and the nature of the catalysts, the doping element and the initial concentration of methyl orange dye. Comparisons of degradation kinetics of methyl orange using TiO2semiconductors have shown that pure TiO2Sachtopore and doped TiO2Sachtopore at 0.1% are less active compared to TiO2P25 and doped TiO2Sachtopore at 0.2% since they provide comparable performance.

In this work, the natural oil shale (NOS) performance was explored for removing methylene blue as textile pollutant. The adsorbent was characterized using X-ray fluorescence (XRF), X-ray diffraction (XRD), and scanning electron microscope (SEM). Further, the response surface methodology (RSM) was investigated to optimize the factors influencing the adsorption of MB onto NOS, using central composite design (CCD). The effect of the experimental parameters on adsorption yield, initial concentration of MB, mass of adsorbent, granulometry and pH, was studied using the response surface methodology (RSM). The obtained results show that the high MB adsorption rate (R% = 98%) is in a basic pH (pH = 12). The analyzes performed, based on residue and analysis of variance (ANOVA), confirmed that NOS had a high efficiency adsorbent capacity and that the chosen model is valid.