Determination of elemental concentrations of radionuclides in Turkish bentonite and calculation of radiogenic heat generation

Assessment of the Levels of Potentially Toxic Elements Contained in Natural Bentonites Collected from Quarries in Turkey

“…In total, 69 natural bentonite samples were collected from BQs located in Ankara (BQ1), Çankırı (BQ2), Çorum (BQ3), Edirne (BQ4), Konya (BQ5), Ordu (BQ6), and Tokat (BQ7) provinces of Turkey, as shown in Fig. . , Bentonite samples were taken from the upper layers of each quarry, that is, from a depth of 0–5 cm. Each bentonite sample placed in polyethylene bags was brought to the sample preparation laboratory.…”

“…Each bentonite sample placed in polyethylene bags was brought to the sample preparation laboratory. After the samples were kept in the open air in the laboratory for a while, they were dried in a furnace at 110 °C for 5–10 h to remove moisture . The dry samples were grounded and powdered to make them fit the calibrated powder geometry in the energy-dispersive XRF (EDXRF) spectrometer. , Each powder sample was homogenized with an agate pestle and made ready for elemental analysis …”

“…EDXRF and wavelength-dispersive XRF spectroscopy are used for qualitative and quantitative multi-element analysis of major, minor, and trace elements in archeological, geological, biological, industrial, food, and environmental samples and require minimal sample preparation. ,− The analysis of PTEs in the bentonite samples was performed with the help of the EDXRF spectrometer (Spectro Xepos, Ametek). The EDXRF spectrometer is equipped with an anode X-ray tube (50 W, 60 kV) consisting of a dual thick Pd/Co mixture. ,,,, The EDXRF spectrometer’s target modifier, which optimizes excitation by using polarization and secondary targets, has many different excitation conditions that guarantee the best detection of all elements from Na to U. Analyses are performed in the He gas environment.…”

“…It uses sophisticated calibration techniques such as “no-standard” calibration, often based on the basic parameters method. Soil-certified reference material (NIST SRM 2709) was used for quality assurance of the EDXRF system. ,,,, Sample containers prepared for each bentonite sample were placed in an automatic sampler, and the analysis procedures were completed by counting for 2 h. The total uncertainty of the analytical procedure is between 2 and 15%. The XRF spectrum of each bentonite sample obtained was evaluated with the help of the software installed in the system.…”

“…Natural and modified bentonites are used either directly or as industrial raw materials in a wide range of applications such as drilling muds, pet litters, waterproofing and sealing applications, animal feed additives, oil and grease absorbents, agricultural carriers, filtration, clarification, decolorizing agents, asphalt emulsions, catalysts, and additives in the food, cosmetic, pharmacological, and construction industries, and so forth depending on their physical and chemical properties . There are considerable reserves of bentonite (approximately 370 million tons) in Turkey, distributed in different geographical regions, especially in Central Anatolia and the Black Sea Region . With an annual production of 1.5 million tons, Turkey is the fifth highest bentonite-producing country after the USA, China, India, and Greece .…”