The influence of introducing benzothiazole and benzimidazole as a pending groups into the repeating unit of PVC has been studied on the bases of photostability measurements. The photostability of modified polymers were studied by monitoring the carbonyl Index (I CO ), polyene index (I po ) and hydroxyl index (I OH ), all results obtained indicated that PAA, PSS, PNN, PSA and PNA gave lower growth rate of I CO , I PO and I OH with irradiation time with respect to unmodified PVC film (control). The following trends of photostability are obtained PAA>PSS>PNN>PSA>PNA According to the experimental results several reaction mechanisms were proposed depending on the presence of benzothiazole and benzimidazole moieties in the polymer chain. The mode of chain scission was also investigated by measuring the variation of average viscosity molecular weight with irradiation time for modified PVC. The degree of deterioration (α) and the average number of chain scission (S) values were also calculated.

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This paper deals with an advanced colorimetric method used to determine the catalase mimetic activity of V2O5 nanoparticles by measuring the decrease in potassium permanganate concentration in a mixture containing V2O5 and hydrogen peroxide. The experiments were carried out in batch reactor at room temperature for 3 min at wavelength number of 525 nm. Vanadium pentoxide was synthesized by hydrothermal method (reflux) from ammonium metavanadate (NH4VO3) as a precursor and cetyltrimethylammonium bromide as a surfactant. The annealing of the product was carried out for 2 h, at temperatures of 250, 500 and 750 °C. In order to determine the structure and the chemical nature of the nanoparticles prepared, the characterization was carried out by X-ray diffraction and scanning electron microscopic techniques. Atomic force microscopic and thermal gravimetric investigations have shown the decomposition steps of V2O5 at different temperatures. UV–visible spectroscopic technique and Fourier transform spectrometry were used to further characterize the nanoparticles. Advanced colorimetric method was used to study the catalase mimetic activity of the newly synthesized vanadium pentoxide (V2O5) nanoparticles using hydrogen peroxide (H2O2) as substrate. V2O5 nanoparticles resulted in an increase in the catalase mimetic activity with increasing the annealing temperature of the V2O5 nanoparticles. The maximum activity was found at 500 °C, which subsequently decreased with further increase in the annealing temperature.

In this research, manganese oxides (MnO 2 ) nanoparticles were prepared by hydrothermal method using KMnO 4 as a precursor. The final brown-black precipitate MnO 2 nanoparticles as prepared, and annealed at different temperatures (250, 450, and 750 °C) were characterized. The nanoparticles prepared were tested for removal of methylene blue (MB), used as a model dye from water. In order to determine the structure and the chemical nature of the MnO 2 nanoparticles prepared, the characterization was carried out by X-ray diffraction. For the surface morphological studies of nanoparticles, field emission scanning electron microscopy was used. In order to study the surface roughness atomic force microscopy was used for determination of the imaging surface structures in the nm scale. Fourier transform infrared spectrometry was used to investigate the vibrations of functional groups in MnO 2 . The tests for dye removal from water using MnO 2 nanoparticles have been carried out for MnO 2 nanoparticles as prepared and annealed at different temperatures. The process parameters such as speed of shaking, reaction time, and MB concentration were studied at 25 °C temperature to determine the best removal efficiency of methylene blue from water. UV/Visible spectrophotometer was used to follow the MB removal. MnO 2 annealed at 750 °C exhibited the highest MB removal efficiency, 89%, as compared with MnO 2 nanoparticles as prepared and annealed at 250 and 450 °C.

The growing global economy resulted in an incessant increase in transportation and exploitation of oil. Hence, the oil spillage has been considered a serious threat to aquatic and terrestrial ecosystems. Therefore, water purification has been considered a major challenge around the world. There are numerous classical methods available for oil removal from water, but owing to multiple defects and disadvantages, research efforts have focused to find such adsorbents which can improve oil adsorption capability. Traditional adsorbent material typically applied in oil removal includes activated carbon, organoclays, wool, zeolites, etc. These materials suffer from several drawbacks such as low absorption capacity, non-selective absorption, and complicated reusability, whereas nano-adsorbents offer multiple advantages such as having multiple sorption sites, large surface area, short intra-particle diffusion distance, tuneable pore size, and ease of low-temperature modification. Multi-walled carbon nanotubes (MWCNTs) are extensively used adsorbent materials with a strong affinity for the removal of organic pollutants. The functionalization MWCNTs further increase the sorption capacity of adsorbents manifolds to remove organic materials. These nanocomposites are also compatible with green materials and considered environmentally friendly adsorbents. This review paper aims at providing an insight to understand the properties of the MWCNTs and their potential use to adsorb hydrocarbons from water. Moreover, the synthesis methods of those materials, their modification procedures including the functionalization with metal oxide nanoparticles, and applications are also discussed in detail. Graphic abstract