Ding D.,University of South China |
Wang Q.,University of South China |
Wang Q.,Central South University |
Hu N.,University of South China |
And 5 more authors.
Advanced Science Letters | Year: 2012
The contamination of groundwater by NO - 3 in former mining area of uranium mine due to leaching has become major concern. The authors enriched denitrifying microbial culture using the sludge taken from the former uranium mining area North West China. An up-flow fixed-bed denitrifying bacteria (DNB) reactor was developed with the denitrifying culture as inoculum. The effects of pH, ratio of organic carbon versus nitrogen and hydraulic retention time (HRT) on the removal of NO - 3 -N were investigated to examine denitrification performance of the reactor for the treatment of contaminated groundwater from the former mining area. When the reactor was operated at pH 6.5, with influent NO - 3 -N concentration of 1000 mg· L -1 and HRT of 2.5 h, the removal of the NO - 3 -N was 97% with NO - 3-N removal rate of 388 mg· h -1 · L -1 and hydraulic loading rate of 0.35 m 3 · h -1 ·m -3; while with influent NO - 3 -N concentration of 550 mg· L -1 and HRT of 1.4 h, the removal of the NO - 3 -N was 96% with hydraulic loading rate of 0.62 m3 · h -1 ·m -3. Our results indicated that the bioreactor can work with influent pH between 5.0 and 8.0 and the ratio of organic carbon versus nitrogen between 0.6 and 0.8. © 2012 American Scientific Publishers. All rights reserved.
Wang P.-F.,East China Institute of Technology |
Nie W.-B.,Tianshan Uranium Corporation |
Hua R.,East China Institute of Technology |
Liu Y.-H.,East China Institute of Technology |
Hua M.,East China Institute of Technology
Yuanzineng Kexue Jishu/Atomic Energy Science and Technology | Year: 2015
The bone powder was chosen as the adsorbent, and the adsorption of Th(IV) on bone powder in aqueous solution was studied. The physicochemical properties of bone powder were characterized by X-ray diffraction (XRD), infrared spectroscopy (FT-IR) and scanning electron microscope (SEM). The factors affecting the adsorption of Th(IV) in aqueous solution such as initial pH values, the initial concentrations of Th(IV), contact time and temperature were investigated by batch static adsorption experiments, and the adsorption mechanism was also discussed. The results indicate that the adsorption of Th(IV) on the bone powder is strongly dependent on pH, attaining the highest point at pH=3. The adsorption kinetics can be better described by the pseudo-second-order model, and the adsorption process can be well defined by the Langmuir isotherm model, and the maximum monolayer adsorption capacity is 482.50 mg/g. The adsorption process is feasible, spontaneous and endothermic in nature. ©, 2015, Atomic Energy Press. All right reserved.
Peng Z.,East China Institute of Technology |
Luo M.,East China Institute of Technology |
Jiang X.,East China Institute of Technology |
Jiang X.,Tianshan Uranium Corporation |
And 2 more authors.
Xiyou Jinshu/Chinese Journal of Rare Metals | Year: 2011
Synergistic extraction of rhenium with primary amines and tributylphosphate was studied. The effects of initial pH value, composition of the extractant, and volume ratio of organic phase to aqueous phase on the extraction of rhenium were studied. The results showed that the synergistic extraction efficiency of rhenium was above 97% at pH 2~10, while dissolving loss of primary amine (N1923) in acid condition was great. The optimum conditions were obtained with initial pH value of 9.5 with 30% N1923, 50% TBP and 20% sulphonating kerosene as extractant, 3% NaOH as stripping reagent, phase ratio of 1:1. The extraction efficiency was above 99%, and stripping efficiency was above 97%. The distribution ratio of rhenium increased with the increase of initial concentration of rhenium, and the extraction rate of rhenium was not influenced by the uranium existed in aqueous phase, and hardly influenced by nitrate. During the progress of in-situ sulfuric acid leaching technique of uranium, U and Re in the forms of [UO2 (SO4)2]2-, [UO2 (SO4)3]4-, ReO4 - were brought into leaching solution, and simultaneously absorbed by anion exchange resin D231. Uranium was stripped by nitrate or chloride from in-situ leach uranium mining technology resin, then rhenium was stripped by 10% NH4NO3 and 8% NH4OH. It was effective for the recovery of rhenium from desorption solution by primary amines and tributylphosphate synergistic extraction that provided parameters for further industry investigation for recovery of rhenium from uranium ore.