Uranium Wastewater Research Articles

Equilibrium, kinetic and thermodynamic studies on the removal of U(VI) by low cost agricultural waste

In this research, biosorption efficiency of different agro-wastes was evaluated with rice husk showing maximum biosorption capacity among the selected biosorbents. Optimization of native, SDS-treated and immobilized rice husk adsorption parameters including pH, biosorbent amount, contact time, initial U(VI) concentration and temperature for maximum U(VI) removal was investigated. Maximum biosorption capacity for native (29.56mgg−1) and immobilized biomass (17.59mgg−1) was observed at pH 4 while SDS-treated biomass showed maximum removal (28.08mgg−1) at pH 5. The Langmuir sorption isotherm model correlated best with the U(IV) biosorption equilibrium data for the 10–100mgL−1 concentration range. The kinetics of the reaction followed pseudo-second order kinetic model. Thermodynamic parameters like free energy (ΔG0) and enthalpy (ΔH°) confirmed the spontaneous and exothermic nature of the process. Experiments to determine the regeneration capacity of the selected biosorbents and the effect of competing metal ions on biosorption capacity were also conducted. The biomass was characterized using scanning electron microscopy, surface area analysis, Fourier transformed infra-red spectroscopy and thermal gravimetric analysis. The study proved that rice husk has potential to treat uranium in wastewater.

Study on Adsorption of Uranium in Wastewater by Clay

The effectives of pH value, contact time，sorbent dose and different initial concentration were analyzed to study the properties of the adsorption of uranium in wastewater by clay. The results show the highest adsorption capacity was obtained around neutral pH.The amount adsorbed of uranium on clay increase rapidly with increasing initial uranium concentration, but the removal rates of uranium are declined.Clay has a good adsorption capability to uranium with 18.25mg/g of adsorption capacity. The adsorption data on clay are followed by both Langmuir and Freundlich models and the results are well described by Langmuir isotherm. The pseudo-second-order kinetic model is more appropriate for the sorption process.

Biosorption of uranium by magnetically modified Rhodotorula glutinis

Adsorption of uranium from aqueous solution onto the magnetically modified yeast cell, Rhodotorula glutinis, was investigated in a batch system. Factors influencing sorption such as initial solution pH, biomass dosage, contact time, temperature, initial uranium concentration and other common cations were analyzed. Sorption isotherm, kinetic and thermodynamic studies of uranium on magnetically modified R. glutinis were also carried out. The temperature dependent equilibrium data agreed well with the Langmuir model. Kinetic data obtained at different temperatures were simulated using pseudo-first-order and pseudo-second-order kinetic models, the pseudo-second-order kinetic model was found to describe the data better with correlation coefficients near 1.0. The thermodynamic parameters, ΔH°, ΔS° and ΔG° were calculated from the sorption data gained at different temperatures. These thermodynamic parameters showed that the sorption process was endothermic and spontaneous. All results indicated that magnetically modified R. glutinis can be a potential sorbent for uranium wastewater treatment.

Experimental Study on Restoration of Polluted Groundwater from in Situ Leaching Uranium Mining with Sulfate Reducing Bacteria and ZVI-SRB

In the case of in situ leaching of uranium, the primitive geochemical environment for groundwater is changed since leachant is injected into the water beaving uranium deposit. This increases the concentration of uranium and results in the groundwater contamination.Microbial reduction technology by Sulfate reducing bacteria and Zero Valent Iron were employed to treat uranium wastewater. The experiments were conducted to evaluate the influence of anion (sulfate and nitrate) on dealing with uranium wastewater. Experimental results show that the utilization of both SRB system and ZVI - SRB system to process uranium wastewater is affected by sulfate ion and nitrate ion. As the concentration of sulfate radical is lower than 4000mg/L, sulfate-reducing bacteria has no influence on precipitated uranium. However, as the concentration of sulfate is more than 6,000mg/L, uranium removal rate decreases significantly, from 80% to 14.1%. When adding sulfate radical on ZVI - SRB system to process uranium wastewater, its uranium removal rate is higher than SRB system. Low concentration of nitrate contributes to reduction metabolism of SRB. High concentration of nitrate inhibits the growth and metabolism of SRB and affects the treatment efficiency of uranium wastewater. When the concentration of nitrate reaches 1500mg/L, uranium removal rate is less than 0.1%. Nevertheless, as the concentration of nitrate is lower than 1000mg/L, uranium removal rate could reach more than 75%. As existence of nitrate radical, uranium removal rate of SRB by adding ZVI is higher than that without adding.

Analysis of trace level uranium in wastewater using the PIXE method

Trace level uranium in wastewater is a particularly important issue for material accountancy and radiation protection. It is difficult to detect trace level uranium without concentrating wastewater. This study is a discussion of particle-induced X-ray emission (PIXE) analysis that is used to find concentration of uranium easily. In the procedure discussed here, the quantity of solution and backing material are examined to determine how they affect the practicality of taking measurements. Our study resulted in findings that show higher sensitivity, shorter measurement time and wider range of concentration than those obtained by usual methods.

Uptake and recovery of americium and uranium byAnacystisbiomass

Abstract The optimum conditions for the uptake of americium and uranium from wastewater solutions by Anacystis nidulans cells, and the recovery of these radionuclides were studied. The optimum pH range for both actinides was in the acidic region between 3.0 and 5.0. In a pH 3.5 solution with an algal biomass of 70 μg/mL, up to 95% of the Am and U were taken up by the cells. However, the uptake levels were lowered considerably when ethylene dinitnlotetraacetic acid (EDTA) or iron or calcium ions were present in the solutions. Most of the radionuclides taken up by the cells could also be desorbed by washing with salt solutions. Of nine salt solutions tested, ammonium carbonate was the most effective. Our experiments using algal biomass to remove radionuclides from wastewaters showed that about 92% of americium and 85% of uranium in wastewater could be taken up by algal biomass, from which about 46% of the Am and 82% of the U originally present in the wastewater could be recovered by elution with a salt solu...

Performance for PAN-3 chelate fiber for adsorbing and separating trace uranium?determination by ICP-OES

An ICP-OES method is established for polyacrylamidoxime-carboxylic acid chelate fiber (PAN-3) adsorbing and separating trace uranium in waste water. The conditions for quantitative enrichment and desorption uranyl ions are investigated. The stability and the reuse performance of the chelate fiber are discussed. The interference of co-existent ions on uranyl ions as well as the analyses of samples are performed with satisfactory results. The lowest concentration of uranium determined by ICP-OES is 5 μg/l, its RSD is 2.6%.