Safeguarding drinking water is a major public health and environmental concern because it is essential to human life but may contain pollutants that can cause illness or harm the environment. Therefore, continuous research is necessary to improve water treatment methods and guarantee its quality. As part of this study, the effectiveness of coagulation–flocculation treatment using aluminum sulfate (Al₂(SO₄)₃) was evaluated on a very polluted site. Samplings were taken almost every day for a month from the polluted site, and the samples were characterized by several physicochemical properties, such as hydrogen potential (pH), electrical conductivity, turbidity, organic matter, ammonium (NH⁺₄), phosphate (PO₄³⁻), nitrate (NO₃⁻), nitrite (NO₂⁻), calcium (Ca²⁺), magnesium (Mg²⁺⁾, total hardness (TH), chloride (Cl⁻⁾, bicarbonate (HCO₃⁻), sulfate (SO₄²⁻), iron (Fe³⁺), manganese (Mn²⁺), aluminum (Al³⁺), potassium (K⁺), sodium (Na⁺), complete alkalimetric titration (TAC), and dry residue (DR). Then, these samples were treated with Al₂(SO₄)₃ using the jar test method, which is a common method to determine the optimal amount of coagulant to add to the water based on its physicochemical characteristics. A mathematical model had been previously created using the support vector machine method to predict the dose of coagulant according to the parameters of temperature, pH, TAC, conductivity, and turbidity. This Al₂(SO₄)₃ treatment step was repeated at the end of each month for a year, and a second characterization of the physicochemical parameters was carried out in order to compare them with those of the raw water. The results showed a very effective elimination of the various pollutions, with a very high rate, thus demonstrating the effectiveness of the Al₂(SO₄)₃. The physicochemical parameters measured after the treatment showed a significant reduction in the majority of the physicochemical parameters. These results demonstrated that the coagulation–flocculation treatment with Al₂(SO₄)₃ was very effective in eliminating the various pollutions present in the raw water. They also stress the importance of continued research in the field of water treatment to improve the quality of drinking water and protect public health and the environment.

This research aimed to assess the adsorption properties of raw walnut shell powder (WNSp) for the elimination of methylene blue (MB) from an aqueous medium. The initial MB concentration (2–50 mg/L), the mass of the biomaterial (0.1–1 g/L), the contact time (10–120 min), the medium’s pH (2–12), and the temperature (25–55 °C) were optimized as experimental conditions. A maximum adsorption capacity of 19.99 mg/g was obtained at an MB concentration of 50 mg/L, a medium pH of 6.93 and a temperature of 25 °C, using 0.2 g/L of WNSp. These conditions showed that the MB dye elimination process occurred spontaneously. Different analytical approaches were used to characterize the WNSp biomaterial, including functional groups involved in MB adsorption, the surface characteristics and morphological features of the WNSp before and after MB uptake, and identification of WNSp based on their diffraction pattern. The experimental isotherm data were analyzed by the Langmuir and Freundlich models for the adsorption of MB dye. The corresponding values of parameter R_L of Langmuir were between 0.51 and 0.172, which confirmed the WNSp’s favorable MB dye adsorption. The experimental kinetic data were examined, and the pseudo-second-order model was shown to be more suitable for describing the adsorption process, with an excellent determination coefficient (R² = 0.999). The exchanged standard enthalpy (H° = −22.456 KJ.mol⁻¹) was calculated using the van ‘t Hoff equation, and it was proven that the adsorption process was exothermic. The spontaneous nature and feasibility of the MB dye adsorption process on WNSp were validated by negative standard enthalpy values (G°) ranging from −2.580 to −0.469 at different temperatures. It was established that WNSp may be employed as a novel, effective, low-cost adsorbent for the elimination of methylene blue in aqueous solutions.

This innovative article provides a detailed description of the successful biosynthesis of zinc nanoparticles (ZnO-NPs) using an aqueous extract of Algerian Date Syrup, also known as molasses. A meticulous process was carried out to determine the optimal calcination temperature for ZnO-NPs, a crucial step in the preparation of these nanoparticles. The study was further extended by creating ZnO/rGOx nanocomposites through a hydrothermal method, varying the concentrations of reduced graphene oxide (rGO) at 5%, 10%, and 15%. The characteristics of the nanocomposites were thoroughly explored, encompassing chemical, optical, and morphological aspects, using sophisticated analysis techniques such as scanning electron microscopy (SEM), UV-visible diffuse reflectance spectroscopy (UV DRS), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). These analyses provided an in-depth understanding of the structure and properties of the nanocomposites. The centerpiece of this study is the evaluation of the photocatalytic degradation capacity of ZnO-NPs and ZnO/rGOx nanocomposites. These materials have demonstrated their ability to act as cost-effective and environmentally friendly photocatalysts for wastewater treatment. Experiments on methylene blue degradation under UV irradiation were conducted, yielding impressive results: a degradation efficiency of 86.6% was achieved in 140 min using 1 g/L of ZnO-NPs, and this rate reached 100% with the ZnO/rGO catalyst in the same time frame, highlighting its superiority as a photocatalyst. Furthermore, this study examined the variables affecting the photocatalysis experiment, including the solution’s pH and the amount of catalyst. The results revealed that the ZnO/rGO photocatalyst reached its optimal efficiency under neutral pH conditions and at a concentration of 1 g/L, providing crucial information for practical use of these materials. This enriched article highlights the promising potential of ZnO-NPs and ZnO/rGOx nanocomposites as efficient photocatalysts for methylene blue degradation, paving the way for significant environmental applications in wastewater treatment.