جستجوی مقالات مرتبط با کلیدواژه « اورانیل » در نشریات گروه « فیزیک »

Heavy metal ions have increased wastewater production with the development of various nuclear activities. One of the most significant metal ions that harm the environment and living organisms, especially humans, is the uranyl ion. There are many methods to remove metal ions, and biological adsorption is the cheapest and most efficient method. In this research, the absorption of uranyl ions from aqueous solutions from tea waste has been studied. Due to the presence of various functional groups such as carboxyl, hydroxyl, amine, etc, tea wastes have good cations adsorption ability. The effective parameters in adsorption including pH, adsorbent dose, temperature, initial uranyl concentration, and contact time parameters were investigated. Response surface methodology (RSM) was used to conduct experiments and analyze the results. The optimum conditions for uranyl adsorption by tea waste adsorbent were pH = 3.9, temperature 25°C, adsorbent dose 0.275 g, initial concentration of uranyl 10 mg/L, and contact time 90 minutes. Using Freundlich's isothermal and pseudo-second-order models, we fitted the most accurate isothermal and kinetic models. Results showed that tea waste was a good bio adsorbent for uranyl adsorption from real wastewater with a 93.50% adsorption rate.

Magnetic hydroxyapatite nanoparticles (Fe3O4/HAP) are prepared in the present work to remove uranyl ions via copercipitation method for the first time. The sorbent was prepared with the weight ratio of magnetic nanoparticles to hydroxyapatite (Fe3O4/HAP) as (1:1), (1:2), (1:3), and (1:5). After finding physical, chemical, and magnetic features, their ability to absorb uranyl ions was examined via UV-Vis method, measuring the absorbance of element complex with arsenazo (III). The effects of parameters such as temperature, pH, contact time, rate of the adsorbent, the concentration of uranyl, and the effects of interference of other ions on the removal of uranyl were analyzed. Also, the experiments showed that the highest rate of uranyl was absorbed by using 0.015 g Fe3O4/HAP (1:5) during 150 min at pH equal to 7. The prepared nanoparticles in 17±2 nm could absorb uranyl in the concentration range of 0.2-100 ppm, eliminating over 96% of uranyl. The absorbing capability of 99.82 mg/g was obtained at 25°C. The results indicate the high potential of the prepared nano-particles in absorbing and eliminating uranyl and show its capability in the waste water containing uranyl.