Nanocrystalline NdFeO3 perovskite oxide was prepared by the combustion method using polyvinyl alcohol (PVA) and corresponding metal nitrate precursors under optimum process conditions, using a solution with a pH of 2, a metal/PVA molar ratio of 1:3, and a calcination temperature of 600 °C, and was characterized by x-ray diffraction, scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller nitrogen adsorption and desorption, energy dispersive x-ray spectroscopy, Fourier transform infrared spectroscopy, laser Raman spectroscopy, and thermogravimetric and differential thermal analysis. The synthesized perovskite NdFeO3, which had an average size of 20 nm and a relatively high surface area of 20 m2 g−1, was investigated for adsorbing hazardous arsenate from aqueous solution. Arsenate adsorption by perovskite NdFeO3 is a pH-dependent process with a high adsorption capacity at pH levels between 4 and 7 and a maximum As(V) adsorption capacity of 126.58 mg g−1, higher than most arsenate adsorbents reported in the literature. Kinetic and equilibrium data of reaction under the experimental conditions are best described by a pseudo-second-order and the Langmuir isotherm equation. The values of enthalpy, Gibbs free energy and entropy changes (ΔH0 = +63.916 kJ mol−1, ΔG0 = −6.551 kJ mol−1 to −14.021 kJ mol−1 at T = 283−313 K, ΔS0 = +0.249 kJ mol−1 K−1) suggested that the reaction was endothermic, spontaneous, and took place with increasing entropy.

In a world where demands for freshwater are ever-growing, wastewater remediation becomes a global concern. Especially, water, which is contaminated by oil, dyes, poses challenges to the management of water resources. The development of innovative processes for wastewater treatment is still a major obstacle. With regard to its fast removal rate and environmental compatibility, cellulose aerogel composites are recently considered as a potential contributor for water remediation. In this study, cellulose aerogel composites are fabricated using the sol-gel method from two-agroindustrial wastes: pineapple leaf fibers and cotton waste fibers in alkali-urea solution followed by freeze-drying. The prepared cellulose aerogel composites are extremely lightweight with a low density (0.053−0.069 g.cm −3 ) and high porosity of nearly 95%. It is worth noting that the mechanical strength of the cellulose aerogel composites is remarkably improved with their Young's modulus increasing by 5-9 times compared to that of the previous aerogel composites using polyvinyl alcohol as a binder. The as-synthesized aerogel composites are directly applied to adsorb cationic methylene blue and exhibit a maximum adsorption uptake of 34.01 g.g -1 .The methyltrimethoxysilane-coated cellulose aerogel composites also show their ability to deal with oil pollution with a maximum oil adsorption capacity of 15.8 g.g −1 within only 20 sec. Besides the oil removal, our developed cellulose aerogel composites have demonstrated their capability in treating dye-contaminated wastewater for the first time based on their evidenced ability to eliminate methylene blue.

The photocatalytic BiFeO3 perovskite nanoparticles were fabricated by gel combustion method using polyvinyl alcohol and corresponding metal nitrate precursors under the optimum mild conditions such as pH 2, gel formation temperature of 80 °C, metal/polyvinyl alcohol molar ratio of 1/3, metal molar ratio Bi/Fe of 1/1 and calcination temperature at 500 °C for 2 h. The prepared sample was characterized by x-ray diffraction, field scanning electron microscopy, transmission electron microscopy, Brunauer–Emmetl–Teller nitrogen adsorption method at 77 K, energy dispersive x-ray spectroscopy, ultraviolet-visible light spectrophotometry, and thermal analysis. The effects of molar ratios of starting material and calcination temperature on phase formation and morphology were investigated. The degradation of methylene blue, methylene orange and some toxic organic compounds such as phenol and diazinon under visible light irradiation by photocatalytic BiFeO3 nanoparticles were evaluated at different parameters and conditions such as the light intensity determined from the light source to the measured sample, the addition H2O2, reaction time and the regeneration performance. Obtained results showed that the synthesized perovskite BiFeO3 nanoparticles for the optimized sample have a size smaller than 50 nm and the high mean surface area of 50 m2 g−1. Degradation efficiency was almost 90.0% for methylene blue and 80.0% for methylene orange with added H2O2 after 30 min of reaction. After the 3rd time of regeneration, the BiFeO3 nanoparticles still have 92.8% of the degradation performance for removing methylene blue. Phenol and diazinon toxic compound were degraded with the performance of 92.42% and 85.7%, respectively, for 150 min

Polyurethane (PU) coating degrades quickly under the irradiation of ultraviolet (UV). Thus, increasing the durability of the coating is necessary. In this study, porous CeO2-SiO2 nanocomposites (CS-NCs) were used to disperse into the PU matrix. The CS-NCs were prepared by a sol-gel combustion method using polyvinyl alcohol as precursors. Prepared nanocomposites were characterized by x-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM) as well as Energy dispersive x-ray (EDX) mapping analysis. Next, the prepared nanocomposites were employed for the preparation of PU coatings. The loading of nanoparticles was varied between 0.1% and 2.0%. These coating properties were investigated by using FTIR and UV–vis spectroscopy. As also in this study, these coatings were subjected to UV exposure with accelerated weather testing. The structural changes were characterized by applying FTIR analysis and measuring gloss and color deviation. The results indicate that incorporating nanocomposites into the polymer matrix improves the UV-durable properties of the PU matrix.