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In recent years, addition of nanoparticles to fluids and polymers has been used as a way of modifying rheological properties. Poly(vinyl alcohol) (PVA) and titanium dioxide (TiO2) nanoparticles aqueous composite nanofluids were prepared through the use of ultrasonic vibration. In fact, ultrasonic vibration is an advantageous method for nanoparticle dispersion. The preparation method prevents reduction of the polymer's molecular weight. TiO2 nanoparticles with different concentrations were employed to investigate the rheological characteristics of composite nanofluids. Rheological characteristics of base fluids and composite nanofluids were measured at different temperatures. Based on the results, all composite nanofluids, as well as base fluids, exhibited non‐Newtonian behavior and rheological characteristics of composite nanofluids, following the Herschel‐Bulkley model. In addition, model parameters are functions of temperature, PVA, and TiO2 nanoparticle concentrations. Also, two‐way interactions among temperature, PVA, and TiO2 nanoparticle concentrations affect flow index and consistency index of the Herschel‐Bulkley model. J. VINYL ADDIT. TECHNOL., 23:234–240, 2017. © 2015 Society of Plastics Engineers

Imidaclopride is an insecticide widely used for pest control in agriculture around the world. It acts on the central nervous system of insects, while posing lower toxicity to mammals. This is an organic material made of Pyridinium, Dihydroimidazol and Nitramide. This structure poses a threat to the environment and humans. Until now, different types of methods have been used for elimination of this organic pollution. Recently, advanced oxidation processes (AOPs) are presented as a proposed method to remove this organic pollution. Photocatalytic degradation is also used as an efficient method for destruction of organic structures. In this study, the effect of titanium dioxide (TiO) nanoparticle as a photocatalyst activated by UV irradiation is investigated. The new design of the reactor was prepared with coaxial cylinders in which the inner cylinder is rotated at a constant speed. The reactor worked in two batch and continuous modes. The results show that the UV irradiation is more effective than activated TiO nanoparticle, as the designed reactor with UV irradiation eliminated Imidaclopride in less than 2 hours.

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