Precursor solution prepared by evaporation deamination complex method for solvent separation of Mo and W by H_2O_2-complexation

An novel method on preparation of precursor solution for solvent separation of molybdenum （Mo） and tungsten （W） by hydrogen peroxide （H2O2）-complexation from the ammonium tungstate solution containing high Mo was studied. The precursor solution was obtained via evaporation deamination and H202-complex transformation processes. Then it was extracted with a mixture extractant of tri-alkyl phosphine oxide （TRPO） and tributyl phosphate （TBP） to separate Mo and W. The results indicated that the evaporation deamination complex method reduced the acid consumption by more than 90% in comparison with the traditional directly acid regulation complex method. The transformation rates of W and Mo were higher than 95% and the decomposition rate of H202 was less than 15% at a 1.8-1.9 times H202 dosage, 45-50 ℃, initial pH of 1.80-1.90, and transformation volume ratio of 100% for 60 min in the H2O2-complexation transformation process. The minimum extraction rate of W was 2%, the maximum extraction rate of Mo was 82.6% and the highest separation coefficient was 76.7 in a single-stage extraction.

STUDY OF COMPOSITE MEMBRANE OF CELLULOSE ACETATE OR POLYVINYL ALCOHOL BLENDED WITH METHYLMETHACRYLATE-ACRYLIC ACID COPOLYMER FOR PERVAPORATION SEPARATION

In this paper, methylmethacrylate-acrylic acid MMA-AA hydrophilic and hydrophobic copolymers were prepared by copolymerization for preparing membrane materials. The composite membrane of cellulose acetate (CA) blended with MMA-AA hydrophobic copolymer was used for the separation of methanol from pentane-methanol mixture. When the methanol concentration was only 1 wt%, the permeate flux still maintained at 350 g/m(2)h and separation factor was as big as 800. The composite membrane of PVA (polyvinyl alcohol) blended with MMA-AA hydrophilic copolymer was used for the separation of ethanol-water mixture. The permeate flux was increased to 975 g/m(2)h at 74 degrees C and the separation factor reached 3000 at 25 degrees C. The PVA/MMA-AA blended membrane surface modified by ammonia plasma was also investigated for separating ethanol-water mixture. Both permeate flux and separation factor of the membrane was improved. However, there was no obvious difference of plasma treatment time in the interval of 20 similar to 40 min.

Recent advances of rhenium separation and enrichment in China： Industrial processes and laboratory trials

China is a major producer of rhenium, which is widely used in aerospace technologies （as superalloy） and petrochemical industries （as catalyst）. There is a gap between the demand and fact for the enrichment of rhenium, due to its rather small content （10-9） in the earth＇s crust. Also, there is no available single occurrence of mineral rhenium. Instead, the rhenium is associated with either molybdenum or copper （of up to 0.2% in content） as a by-product in metallurgical industry. This makes the separation of rhenium from the major mineral metals a challenge. The recent progresses in the separation and enrichment of rhenium were reviewed in this paper, especially, the advances in China. The details of varied separation methods used either in laboratories or factories, such as ion-exchange, solvent extraction, separation utilizing extractive resins, liquid membrane, or novel materials, etc., were elaborated. Comparison of the different methods was disclosed and an outlook on the rhenium chemistry and industry in the future was brought forward.

Extraction and separation of heavy rare earths from chloride medium byα-aminophosphonic acid HEHAPP

The extraction and separation of heavy rare earths（REs） using newly synthesized a-aminophosphonic acid extractant 2-ethylhexyl-3-（2-ethylhexylamino）pentan-3-yl phosphonic acid（HEHAPP, HA） in nheptane were investigated from chloride medium. The extraction stoichiometries of lanthanum, gadolinium, yttrium and lutetium are determined to be REA3 by the slope analysis method. The favorable separation factors of adjacent heavy REs（Ⅲ）,i.e. β（Y/Ho）, β（Er/Y）,β（Tm/Er）,β（Yb/Tm） and β（Lu/Yb）, are determined to be1.87,1.36, 3.21,3.22 and 1.93, respectively, when extracted from a binary system at proper condition. The loading capacities of HA for Ho, Er, Yb and Lu increase in the order Ho 〈 Er 〈 Yb 〈 Lu with the values being 0.201, 0.205, 0.216 and 0.229 mol/L, respectively. So HA would be a potential extractant for the separation of heavy REs（Ⅲ）. Among inorganic acids such as H2 SO4, HNO3 and HCl, HCl is tested to be the most effective stripping agent.

Metal-organic nanosheet assembly ions sieving membrane for precise lithium ion and anion/solvent separation toward robust lithium metal battery

Metal-organic nanosheets(MONs)as a novel material with tunable pore structures and low mass transfer resistance,have emerged as molecular sieves for the separation of gases and liquids.In theory,they can also serve as ion sieves for lithium metal batteries(LMBs),realizing the high-energy and dendritic free LMBs.However,there are rarely relevant reports,because it is difficult to simultaneously balance efficient ion sieving ability,high ion passing rate and high electrochemical stability.Here,we synthesized a stable ultrathin MON[Zn_(2)(Bim)_(4)]([Zn_(2)(Bim)_(4)]Nanosheet,HBim=benzimidazolate),which can achieve both efficient lithium ion sieving ability,high lithium ion passing rate and high electrochemical stability at the same time.The separator assembled by this MON exhibits high Li^(+)transfer number of 0.81 due to the accurate lithium ion and anion/solvent separation.The battery containing such separator shows high lithium ionic conductivity of 0.74 m S cm^(-1)and low activation energy of 0.099 eV,which can be attributed to the nanometer level thickness and the ion sieving effect.What is more,we realized the application of MONs-based ion sieves in LMBs with intercalation cathodes for the first time.And the LiFePO_(4)|Li battery with as-assembled separator demonstrates improved Coulombic efficiency(>99%)and significantly extended cycling life(>1600 cycles)with 80%capacity retention.

Preparation and Properties of Super-hydrophobic Surface by Fluorinated Copolymers

1 Rusults Fig.1 Surface morphologies of the PMMA-PFAEA copolymer filmsa-e, Random copolymer, a-e, synthesized by micro emulsion polymerization,a)b), MMA:FAEA=2:1, c) d), MMA:FAEA=5:1; e) synthesized by solution polymerization, MMA:FAEA=7:3; f) Block copolymer, synthesized by RAFT polymerization, MMA:FAEA=4:1, all solution concentration 1×10-2g/mL Super-hydrophobic surfaces have attracted significant attention recently, and various preparing methods have been reported. Besides these preparing methods, s...