Boron removal from geothermal waters by electrocoagulation

Most of the geothermal waters in Turkey contain extremely high concentration of boron when they are used for irrigation. The use of geothermal waters for irrigation can results in excess amount deposition of boron in soil. On the other hand, a minimal boron concentration is required for irrigational waters. In this study, electrocoagulation (EC) was selected as a treatment process for the removal of boron from thermal waters obtained from Ilica-Erzurum in Turkey. Current density (CD), pH of solution and temperature of solution were selected as operational parameters. The results showed that boron removal efficiency increased from pH 4.0 to 8.0 and decreased at pH 10.0. Although boron removal efficiency was highest at pH 8.0, energy consumption was very high at this pH value compared to other pH intervals. Boron removal efficiency reached to 95% with increasing current density from 1.5 to 6.0 mA/cm(2), but energy consumption was also increased in this interval. At higher temperatures of solution, such as 313 and 333 K, boron removal efficiency increased. At optimum conditions, boron removal efficiency in geothermal water reached up to 95%.     

Radioactivity and heavy metal concentrations in food samples from Rize, Turkey

BACKGROUND: Rize in Turkey was contaminated by the Chernobyl accident in 1986. A comprehensive study was planned and carried out to determine the radioactivity levels and heavy metal concentrations in four food categories collected in Rize in 2008, 2009 and 2010. RESULTS: Tomato showed the highest concentration of ²³⁸U, at 9.43 ± 0.128 Bq kg^?1, whereas the lowest concentration of 0.20 ± 0.02 Bq kg^?1 was measured in aubergine samples. The highest concentration of ²³²Th was measured at 3.22 ± 0.29 Bq kg^?1 in grape samples. ⁴⁰K was found to contribute the highest activity in all the food samples. The highest activity concentration of ¹³⁷Cs was 10.20 ± 4.19 Bq kg^?1, for parsley. The average contribution range of each of the heavy metals to the dietary intake was 0.13–9.14, 0.27–34.63, 0.05–3.62, 0.11–14.97, 0.78–8.51 and 0.01–1.57 mg, respectively, for Mn, Fe, Cu, Zn, Ni and As. CONCLUSION: The range of radioactivity levels in food samples of the present study is of no risk to public health. Heavy metal concentrations of Mn, Fe, Cu, Zn, Ni and As obtained were far below the established values by FAO/WHO limits. Copyright © 2011 Society of Chemical Industry     

Electro-oxidation of pistachio processing wastewater using Ti/Pt mesh-type anodes in batch system

In this study, the treatment of pistachio processing wastewater (PPW) by electro-oxidation method was investigated. Ti/Pt-plated electrodes were used for the anode material, and stainless steel electrodes were used for cathode material. Experimental studies were carried out in batch mode. Stirring speed, supporting electrolyte species and concentration, initial pH value, current density, temperature and dilution ratio were selected as experimental parameters effecting removal efficiency. In Ti/Pt electrode experimental studies on the optimum conditions, chemical oxygen demand (COD), total organic carbon (TOC) and total phenols (TP) removal efficiencies were obtained, respectively, as 99.98%, 70.74% and 100%, and energy consumption value was obtained as 297.5 kW-h/m³ (12.39 kW-h/kg COD, 51.29 kW-h/kg TOC and 64.68 kW-h/kg TP). As a result of the experimental studies, the PPW can be treated by electro-oxidation. Given the results of removal efficiency and energy consumption values, it was concluded the electro-oxidation using Ti/Pt anode very appropriate treatment of PPW.