The goal of the present paper was to synthesize, characterize, and evaluate the performance of the modified composite based on magnetite (Fe₃O₄) and polyvinyl alcohol (PVA). The obtained composite was used to degrade Methyl Orange dye from synthetic wastewater by a laboratory photocatalytic reactor. Various parameters of the photodegradation process were tested: composite dosage, amount of hydrogen peroxide (H₂O₂), and pH. The composite was characterized by Fourier Transform Infrared (FTIR) Spectroscopy, X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). The degradation experiments indicated that the complete dye decolorization depended on the amount of H₂O₂. In addition, the H₂O₂ could accelerate Methyl Orange degradation to more highly oxidized intermediates in the presence of UV light (99.35%). The results suggested that the obtained modified composite could be used to treat wastewater containing various types of dyes.

The main goal of the present paper was to synthesize the polyvinyl alcohol-SiO₂ nanoparticles polymeric membrane by wet-phase inversion method. The efficiency of prepared membranes (without and with SiO₂) was investigated using a versatile laboratory electrodialysis system filled with simulated wastewaters that contain zinc ions. All experiments were performed at following conditions: the applied voltage at electrodes of 5, 10 and 15 V, a concentration of zinc ions solution of 2 g L⁻¹, time for each test of 1 h and at room temperature. The demineralization rate, extraction percentage of zinc ions, current efficiency and energy consumption were determined. The polymeric membranes were characterized by Fourier Transforms Infrared Spectroscopy-Attenuated Total Reflection (FTIR-ATR), Scanning Electron Microscopy (SEM) and Electrochemical Impedance Spectroscopy (EIS). The higher value of percentage removal of zinc ions (over 65%) was obtained for the polymeric membrane with SiO₂ nanoparticles, at 15 V. The FTIR-ATR spectra show a characteristic peak located at ~1078 cm⁻¹ assigned to the Si-O-Si asymmetrical stretching. SEM images of the polymeric membrane with SiO₂ nanoparticles show that the nanoparticles and polymer matrix were well compatible. The impedance results indicated that the SiO₂ nanoparticles induced the higher proton conductivity. The final polymeric membranes can be used for the removal of various metallic ions, dyes, organic or inorganic colloids, bacteria or other microorganisms from different natural waters and wastewaters.

Magnesium–aluminum (Mg-Al) and magnesium–aluminum–nickel (Mg-Al-Ni) layered double hydroxides (LDHs) were synthesized by the co-precipitation method. The adsorption process of Mn²⁺ from synthetic wastewater was investigated. Formation of the layered double hydroxides and adsorption of Mn²⁺ on both Mg-Al and Mg-Ni-Al LDHs were observed by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectrometry (EDX) analysis. XRD patterns for prepared LDHs presented sharp and symmetrical peaks. SEM studies revealed that Mg-Al LDH and Mg-Al-Ni LDH exhibit a non-porous structure. EDX analysis showed that the prepared LDHs present uniformly spread elements. The adsorption equilibrium on these LDHs was investigated at different experimental conditions such as: Shaking time, initial Mn²⁺ concentration, and temperatures (10 and 20 °C). The parameters were controlled and optimized to remove the Mn²⁺ from synthetic wastewater. Adsorption isotherms of Mn²⁺ were fitted by Langmuir and Freundlich models. The obtained results indicated that the isotherm data fitted better into the Freundlich model than the Langmuir model. Adsorption capacity of Mn²⁺ gradually increased with temperature. The Langmuir constant (K_L) value of Mg-Al LDH (0.9529 ± 0.007 L/mg) was higher than Mg-Al-Ni LDH (0.1819 ± 0.004 L/mg), at 20 °C. The final adsorption capacity was higher for Mg-Al LDH (91.85 ± 0.087%) in comparison with Mg-Al-Ni LDH (35.97 ± 0.093%), at 20 °C. It was found that the adsorption kinetics is best described by the pseudo-second-order model. The results indicated that LDHs can be considered as a potential material for adsorption of other metallic ions from wastewater.

The main objectives of this present paper were to indicate the immobilization of nano zerovalent iron (nZVI) onto a polymeric material (Purolite A400) and the synthesis of the polymeric material (A400-nZVI) through sodium borohydride (NaBH₄) reduction. The obtained polymeric material (A400-nZVI) was used for the nitrate ions removal from a simulated groundwater at different conditions. The polymeric materials, without and with nano zerovalent iron (A400 and A400-nZVI), were characterized trough the FTIR, SEM-EDAX, XRD, and TGA analysis. The analysis confirmed the presence of nano zerovalent iron (nZVI) onto the polymeric material (A400). The adsorption capacity of A400-nZVI, used as polymeric adsorbent, was evaluated by kinetic and thermodynamic studies. The obtained experimental results indicated that the nitrate ions reduction was fitted well by models: pseudo-second-order kinetic and Freundlich isotherm. According to the kinetic model results, a reaction mechanism could exist in the stage of reactions. The higher value of removal nitrate (>80%) was obtained under acidic condition. The results indicated that the obtained polymeric material (A400-nZVI) can be considered as a potential polymeric adsorbent for different pollutants from groundwater and wastewater.

Non-degradable plastic bags are a major contributor to marine and soil pollution. They represent a significant percentage of the generated solid waste and can last for hundreds of years in the environment. The aim of the present study was to find alternatives to conventional non-degradable plastic bags by obtaining biodegradable and compostable bags starting from simple materials like starch, poly(lactic acid) (PLA), and glycerol. Increasing the strength and hardness of the polymer was achieved by adding a mineral (talcum). The preliminary studies indicated that two compositions are suitable for advanced testing to produce the initial granular material. These materials were tested for the determination of melt flow index (MFI), Fourier Transform Infrared Spectroscopy (FTIR), and the polymers response to heating (thermogravimetric analysis, TGA and differential scanning calorimetry, DSC). The polymer biodegradability was evaluated by burial in two types of soil. The obtained results were compared with the same set of experiments performed on conventional polyethylene bags. After three months in the soil, only the materials synthesized in this study show signs of accentuated degradation while polyethylene bags are still intact. The surface morphology was explored by scanning electron microscopy (SEM). The results indicated that the biodegradable thermoplastic material meets the requirements of the European standard EN13432/2002 regarding compostable and biodegradable packaging.

Rice is a major dietary component for more than half of the world’s population, and its cultivation requires a careful balance of nutrients to ensure high yields and sustainable practices. Soil-derived N₂O fluxes represent a major environmental challenge with global implications. While agriculture is a necessary activity to feed a growing population, it must evolve to minimize its ecological footprint. This review provides an update on the effects of nitrogen fertilizer application, such as ammonium nitrate (NH₄NO₃), urea (CO(NH₂)₂), ammonium sulfate ((NH₄)₂SO₄), and calcium ammonium nitrate (CAN), on N₂O emissions from rice cultivation. The role of various nitrification inhibitors (e.g., dicyandiamide (DCD), 2-chloro-6-(trichloromethyl) pyridine (nitrapyrin) and 3,4-dimethylpyrazole phosphate (DMPP)) in minimizing the release of N₂O from soils to the atmosphere was also discussed. Here, we described N₂O production by nitrification and denitrification processes in the paddy rice field, and then summarized the strategies, such as optimized fertilizer use, improved drainage and water management, and the use of organic amendments, that can enhance crop productivity while promoting sustainable reductions in N₂O emissions.