## 1 Introduction  
Water pollution is a worldwide problem and it has a dramatic impact on human health and aquatic life. In modern agriculture, the use of herbicides is intensively increasing to control the spread of weeds and protect crop growth [1]. Bentazon is a widely used herbicide, belongs to the thia-diazing group of chemicals, and it is specifically used in rice and soybean cultivations. At natural pH, bentazon high solubility and mobility in the soil contribute to pollution of surface and underground water [2]. Similarly, almost 80 million tons of dyes are produced annually worldwide and used in medical laboratories and industries such as textiles, paper, paint, food, and cosmetics. The release of a significant amount of these dyes into waterbodies disturbs the stability of ecosystems [3]. Nile blue dye is a potential photosensitizer that can be used in photodynamic therapy to treat malignant tumors. Its release in the environment without any pretreatment is harmful to the respiratory tract if inhaled and causes skin and eye infections [4]. The discharge of polluted water with dyes and herbicides without any pretreatment represents a serious threat. Consequently, the development of cost-effective and eco-friendly methods for dye-containing water treatment is an urgent matter. Different biological, physical, and chemical methods have been used for the degradation of organic dyes and herbicides, such as reverse osmosis, coagulation, sedimentation, and the advanced oxidation process [5]. Notably, the advanced oxidation process (AOP) is a promising technique for the removal of organic pollutants (dyes and herbicides) by using semiconductor nanostructures due to the low cost, ecofriendly nature, high degradation efficiency, and chemical stability [6]. Metal oxide-based catalysts have been applied for the removal of organic pollutants including Fe\({}_{2}\)O\({}_{3}\), ZnO, TiO\({}_{2}\), MgO, and Al\({}_{2}\)O\({}_{3}\)[7; 8; 9; 10]. Among these, titanium dioxide (TiO\({}_{2}\)) has gained remarkable attention as a photocatalyst due to high photocatalytic activity towards organic pollutants, that can be combined to large surface area and adequate porosity. Titanium dioxide is the ninth most abundant chemical compound on the earth's crust, and it is present in three different phases: anatase, rutile, and brookite. Anatase TiO\({}_{2}\) is one of the stable crystalline phases of titania and has a high electron mobility and low recombination rate [11; 12; 13]. Owing to these properties, anatase TiO\({}_{2}\) is one of the most widely used photocatalysts for the light-driven degradation of organic pollutants. However, when TiO\({}_{2}\) nanoparticles were employed at the pilot scale, some disadvantages were encountered in the scaling up such as the cost, stability, and aggregation of TiO\({}_{2}\) nanoparticles, which may reduce the surface area and reduce the reactivity. In terms of toxicity, TiO\({}_{2}\) nanoparticles can pose health risks such as respiratory issues, skin irritation, and toxic effects on the aquatic system [14; 15]. Numerous methods have been adopted for the fabrication of TiO\({}_{2}\) nanoparticles such as the co-precipitation method, hydrothermal synthesis, chemical vapor deposition, and sol-gel method. Among these, sol-gel is one of the most effective, low-cost, fast and feasible techniques to synthesize nanoparticles [16; 17; 18]. In this work, we prepared TiO\({}_{2}\) nanoparticles by the sol-gel method using TiCl\({}_{4}\) as a precursor. To investigate the physicochemical properties, the prepared TiO\({}_{2}\) photocatalyst was characterized by different characterization techniques such as X-ray diffraction (XRD), UV-Visible spectroscopy (UV-Vis), and Fourier-transform infrared spectroscopy (FTIR). Surface morphology was determined by scanning electron microscopy (SEM).