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| 1 | Kinetics study on leaching of rare earth and aluminum from polishing powder waste using hydrochloric acid显示文摘In this study,a novel hydrometallurgical process consisting of hydrochloric acid three-stage countercurrent leaching and solvent extraction was proposed to recover rare earth oxide(REO)from the rare earth polishing powder waste(REPPW).The effects of HCl concentration,liquid-solid ratio(L/S ratio),temperature and time on the leaching yields of rare earths(in REO)and aluminum(in Al2O3)were studied.The result shows that the leaching yields of REO and Al2O3 are 90.96%and 43.89%respectively under the optimum leaching parameters of HCl concentration=8.00 mol/L,L/S ratio=4 mL/g,leaching temperature=353 K and leaching time=180 min.Meanwhile,the leaching kinetics of REO and Al2O3 were investigated in this study.The leaching behaviors of REO and Al2O3 follow a shrinking sphere/core model and the general leaching process is controlled by the surface chemical reaction.The leaching activation energies of REO and Al2O3 are 9.86 and 13.68 kJ/mol,respectively.The leaching yield of each substance in three-stage countercurrent leaching is improved substantially compared with single-stage leaching,with a change from 90.96%to 95.38%for REO and from 43.89%to 46.22%for Al2O3,respectively.Especially,the total concentration of REO in three-stage countercurrent leaching solution is greatly increased to above 300 g/L,and the acidity of which is decreased to ca.pH=2,which is conducive to subsequent solvent extraction directly.High purity REO(99.92%)is obtained by solvent extraction separation,oxalate precipitation and calcination.The total recovery yield of REO is 85.13%. | Xitao Wu Zhijian Wang Chuping Xia Xuefeng Shi Tianzong Luo Xinjun Bao Rongli Liu Shengzhong Xie | 2020 | Journal of Rare Earths2020，38，9： | 3 |
| 2 | Cloning and Expression of a Chitinase Gene from Serratia marcescens Strain C8-8显示文摘A 1692 bp long chitinase-encoding chiA gene was cloned from the genomic DNA of Serratia marcescens strain C8-8 by PCR, which was speculated to encode a 563 aa long polypeptide chain with molecular weight of about 60.9 kD.Homology analysis showed that the chiA gene sequence cloned from C8-8 shared the highest similarity with chiA sequences from Serratia marcescens strains 141 (DQ 990373.1) and 14041 (DQ 493896.1), which reached 99%.Domain analysis showed that N-terminal (23 aa) of the chiA gene cloned from C8-8 harbored typical signal peptide sequence, while C-terminal harbored the other two domains, including the PKD region (73 aa) and chitinase catalytic region (387 aa).The PCR fragment was digested with restriction endonucleases and cloned into plasmid pET28a.The recombinant plasmid pET28a-chiA was firstly transformed into Escherichia coli DH5, and then transformed into expression host E.coli DH3 to express chiA gene.The recombinant strain DH3 chiA could produce transparent hydrolysis circles on the colloidal chitin plate induced by isopropyl-1-thiogalactopyranoside (IPTG).SDS-PAGE electrophoresis analysis showed that, a protein with relative molecular weight of about 60 kD was expressed by the recombinant strain DH3 chiA, which was consistent with the except molecular weight.After initial purification, biological activity test showed that the recombinant expression product could hydrolyze chitin, which produced transparent hydrolysis circles on the colloidal chitin plates.Results indicated that chiA gene from Serratia marcescens strain C8-8 had biological functions and could be utilized as a potential biological control factor. | Youzhou LIU Chuping LUO Yongfeng LIU Zhiyi CHEN | 2013 | Agricultural Biotechnology2013，2，3： | 3 |
| 3 | Genome Sequence of the Plant Growth-Promoting Rhizobacterium Bacillus sp. Strain 916显示文摘 | Xiaoyu Wang Chuping Luo Zhiyi Chen | 2012 | Journal of Bacteriology2012，，19： | 1 |
| 4 | Characteristics of intracellular polyphosphate granules and phosphorus-absorption of a marine polyphosphateaccumulating bacterium, Halomonas sp. YSR-3显示文摘Halomonas sp.YSR-3 was isolated from the Yellow Sea and identified as a polyphosphate-accumulating bacterium and the characteristics of its intracellular polyphosphate(polyP)granules and phosphorus absorption were studied.Most YSR-3 cells stored one or two polyP granules in regular appearance and high-density.The diameter of the granules was about 400 nm measuring by a transmission electron microscope(TEM).After stained with 4,6-diamidino-2-phenylindole(DAPI)and visualized by a fluorescence microscope,the cells turned blue and the granules were bright yellow.The composition of granules includes P(major ingredient),Mg,S,K,and Ca as detected by an energy dispersive X-ray spectrometer(EDS).When inorganic phosphorus(po34-)and ferric ion(Fe3+)were added into media,the biomass increased and the cells formed intracellular polyP granules owing to the phosphorus assimilation from media.The YSR-3 obtained higher biomass by adding 0.02 g/L FePO4 than 0.005 g/L and 0.01 g/L FePO4;however,the phosphorus absorption was higher with 0.01 g/L FePO4 than 0.005 g/L and 0.02 g/L FePO4.The optical density at wavelength 480 nm(OD480nm)was 0.79 and 100%cells could form intracellular polyP granules.These results show that strain YSR-3 is able to acquire higher biomass and absorb more inorganic phosphorus when 0.01 g/L FePO4 is added.The characteristics of absorbing and storing phosphorus as intracellular inorganic polyP granules have a potential for application in high-efficiency phosphorus removal in wastewater treatment. | REN Shiying LI Xiangqian YIN Xiulian LUO Chuping LIU Fei | 2020 | Journal of Oceanology and Limnology2020，38，1： | 0 |
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