The purpose of this study was to examine the nitrate adsorption by cobalt ferrite (CFO) nanoparticles. The adsorbent was synthesized by co-precipitation method and its structure was characterized using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD) and Vibrating-Sample Magnetometer (VSM). In batch adsorption studies, the effects of various parameters like pH (3–11), adsorbent dose (0.2–0.8 g/L), contact time (5–120 min), initial nitrate concentration (50–200 mg/L), and temperature (283–313 K) on the adsorption process were examined. The results of this study indicated that the maximum adsorption capacity was 107.8 mg/g (optimum condition pH = 3, adsorbent dosage: 0.2 g/L, nitrate concentration: 200 mg/L, contact time: 20 min and temperature 313 K). The adsorption isotherm had a proper match with Langmuir (R2 = 0.99) and Freundlich (R2 = 0.99) models. The adsorption of nitrate by CFO has followed pseudo second-order kinetics. The results of the thermodynamics of the nitrate adsorption process by CFO showed that all the values of ΔG, ΔH and ΔS were positive. Therefore, this process was endothermic and non-spontaneous.

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The importance of water in everyday life is clear for humans and living creatures. In addition to supplying the water required for the body, it also contains necessary minerals. An increase or decrease in these minerals is responsible for various diseases and problems. Due to the growing consumption of treated water in Birjand, Iran and the need for the continuous monitoring of the quality of treated water, this descriptive research aimed to determine the chemical and microbiological quality of treated water of desalination stations in Birjand from September 23rd, 2015to March 19th, 2016 (autumn and winter). Samples were directly taken from the desalination stations of Birjand. Physical and chemical tests were performed according to the Standard Methods.The results were compared with national standards as well as World Health Organization (WHO) guidelines. The results showed that almost all measured chemical and bacterial characteristics were less than the national and international standards. Also, the samples were standard in terms of coliforms and fecal coliforms. In some stations the concentrations of free residual chlorine and also magnesium were higher than standards. Therefore, periodic investigation of quality parameters is recommended in all desalination stations to reflect the results to authorities.

Bentonite is an inorganic clay material that is often easily dispersed as fine particles by air and water circulation, and most people are exposed to different concentrations of bentonite particles. Therefore, the inhaled effects of bentonite nanoparticles (BNPs) were studied in Wistar rats. Seventy-five rats were divided into five groups of 15: four exposure groups (0.1, 0.5, 2, and 10 mg/m3 of BNPs) and one control group. The rats were exposed for 30, 60, and 90 days to BNPs for 5 days a week (6 h/day) in whole-body inhalation chambers. Blood samples were collected to measure the levels of antioxidant activity of the contents such as total antioxidant capacity (TAC) and malondialdehyde (MDA). X-ray diffraction and scanning electron microscopy were used to identify nanoparticles. The results showed no significant difference in the effect of nanoparticles on levels of TAC and MDA in the studied groups based on the concentrations of nanoparticles. However, the level of MDA increased significantly with extending exposure time; there was a significant increase in the level of MDA content 90 days postexposure compared to 30 days postexposure at concentrations of 0.5, 2, and 10 mg/m3. Histopathological examination showed that inhalation exposure of rats to BNPs led to different histopathologic responses in the lung tissue, such as inflammatory infiltration, granulomatous inflammation, acute neutrophilic reaction in the early stages, and lung fibrosis. At the lowest concentration, BNPs have low or no toxicity, and inhalation of these nanoparticles at low concentrations does not affect the levels of MDA and TAC content. However, increased concentration and exposure time caused correspondingly greater increases in MDA and more damage to lung tissue.