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Chinese Journal of Chemical Engineering 2019年第3期27卷 519-527页

作者： Liang Chen Yunren Qiu School of Chemistry and Chemical Engineering Central South University

Removal of cadmium(Ⅱ) ions from dilute aqueous solutions by complexation–ultrafiltration using rotating disk membrane was investigated. Polyacrylic acid sodium(PAAS) was used as complexation agent, as key factors of complexation, pH and the mass ratio of PAAS to Cd^(2+)(P/M) were studied, and the optimum complexation–ultrafiltration conditions were obtained. The effects of rotating speed(n) on the stability of PAA–Cd complex was studied with two kinds of rotating disk, disk Ⅰ(without vane) and disk Ⅱ(with six rectangular vanes) at a certain range of rotating speed. Both of the rejection could reach 99.7% when n was lower than 2370 r·min^(-1) and 1320 r·min^(-1), for disk I and disk Ⅱ, respectively. However, when rotating speed exceeds a certain value,the critical rotating speed(n_c), the rejection of Cd(Ⅱ) decreases greatly. The distribution of form of cadmium on the membrane was established by the membrane partition model, and the critical shear rate(γ_c), the smallest shear rate at which the PAA–Cd complex begins to dissociate, was calculated based on the membrane partition model and mass balance. The critical shear rates(γ_c) of PAA–Cd complex were 5.9 × 10~4 s^(-1), 1.01 × 10~5 s^(-1),and 1.31 × 10~5 s^(-1) at pH = 5.0, 5.5, and 6.0, respectively. In addition, the regeneration of PAAS was achieved by shear induced dissociation and ultrafiltration.

关键词： Complexation-ultrafiltration Membrane Regeneration shear stability Critical shear rate shear induced dissociation

Enhancement of shear stability of a Fe-based amorphous alloy using electrodeposited Ni layers

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Journal of Materials Science & Technology 2018年第12期34卷 2283-2289页

作者： Y.C.Wang X.M.Luo L.J.Chen H.W.Yang B.Zhang G.P.Zhang School of Materials Science and Engineering Shenyang University of Technology Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences Key Laboratory for Anisotropy and Texture of Materials Ministry of EducationSchool of Materials Science and EngineeringNortheastern University

Tensile and fracture behaviors of sandwich-structured composites consisting of a Fe-based amorphous layer with a constant thickness and ultrafine-grained Ni layers with different thicknesses were investigated. The results indicate that the initiation and the stable propagation of the shear band in the amorphous layer was dominated by the Ni layers due to their strong constraint role. The catastrophic fracture of the amorphous layer was postponed in the sandwich composites through properly increasing the constrained Ni layer thickness, which effectively decreased the shear stress on the shear fracture planes of the amorphous layer, and thus led to stable propagation of the primary SB characterized by the increase in the smooth region size of the shear band.

关键词： Sandwich-structured composites Amorphous alloy shear stability Plasticity Fracture

Recovery of Hg(Ⅱ)from aqueous solution by complexation-ultrafiltration using rotating disk membrane and shear stability of PMA-Hg complex

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Journal of Central South University 2020年第9期27卷 2507-2514页

作者： ZHOU Han QIU Yun-ren CHEN Yu-xin School of Chemistry and Chemical Engineering Central South UniversityChangsha 410083China

Copolymer of acrylic acid and maleic acid(PMA)was used to remove Hg^2+from aqueous solution by complexation-ultrafiltration(C-UF)through rotating disk membrane(RDM).The effects of P/M(mass ratio of PMA to metal ions),pH and rotation speed(N)on the interception of Hg^2+were *** interception could reach 99.7%at pH 7.0,P/M 6 and N less than 1890 r/*** shear stability of PMA-Hg complex was studied by *** critical rotation speed,at which the interception starts to decrease,was 1890 r/min,and the critical shear rate,the smallest shear rate at which PMA-Hg complex begins to dissociate,was 2.50×10^5s^-1 at pH ***,the critical radii were obtained at different rotation speeds and *** results showed that the critical radius decreased with the rotation speed and increased with *** induced dissociation coupling with ultra?ltration(SID-UF)was efficiently used to recover Hg^2+and PMA.

关键词： complexation-ultrafiltration shear induced dissociation rotating disk membrane shear stability wastewater treatment

Removal of Co(Ⅱ) from aqueous solution by complexation-ultrafiltration and shear stability of PAA-Co complex

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Transactions of Nonferrous Metals Society of China 2019年第6期29卷 1346-1352页

作者： Jing GAO Yun-ren QIU Mao-lin LI Hui-shang LE School of Chemistry and Chemical Engineering Central South University Changsha 410083 China Changsha Research Institute of Mining and Metallurgy Co. Ltd. Changsha 410012 China

Removal of Co(Ⅱ) from aqueous solutions by complexation-ultrafiltration was investigated using polyacrylic acid sodium(PAAS) as complexing agent with the help of rotating disk membrane,and the shear ability of PAA-Co complex was studied. The effects of the mass ratio of PAAS to Co(Ⅱ)(P/M) and pH on the rejection of Co(Ⅱ) were studied,and the optimum conditions were P/M=8 and pH=7. The rejection of Co(Ⅱ) was over 97% when the rotating speed of the disk(n)was less than 710 r/min at the optimum P/M and pH. The distribution of the forms of cobalt on the membrane surface was established by the membrane partition model, and the critical shear rate,the smallest shear rate at which the PAA-Co complex begins to dissociate,was calculated to be1.4×10^4 s^-1,and the corresponding rotating speed was 710 r/*** PAA-Co complex dissociated when the shear rate was greater than the critical one. The regeneration of PAAS and recovery of Co(Ⅱ) were achieved by shear-induced dissociation and ultrafiltration.

关键词： shear stability critical shear rate PAA-Co complex shear-induced dissociation complexation-ultrafiltration

Drag reduction behavior of hydrolyzed polyacrylamide/xanthan gum mixed polymer solutions

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Petroleum Science 2017年第2期14卷 412-423页

作者： Mehdi Habibpour Peter E. Clark School of Chemical Engineering Oklahoma State University Stillwater OK 74078 USA

Partially hydrolyzed polyacrylamide（HPAM）as the main component of slickwater fracturing fluid is a shear-sensitive polymer,which suffers from mechanical degradation at turbulent flow *** different concentrations of HPAM as well as mixtures of polyacrylamide/xanthan gum were prepared to investigate the possibility of improving shear stability of *** reduction（DR）measurements were performed in a closed flow *** HPAM solutions,the extent of DR increased from 30%to67%with increasing HPAM concentration from 100 to1000 *** the HPAM solutions suffered from mechanical degradation and loss of DR efficiency over the shearing *** indicated that the resistance to shear degradation increased with increasing polymer *** efficiency of 600 wppm xanthan gum（XG）was 38%,indicating that XG was not as good a drag reducer as *** with only 6%DR decline,XG solution exhibited a better shear stability compared to HPAM *** HPAM/XG solutions initially exhibited greater DR（40%and 55%）compared to XG,but due to shear degradation,DR%dropped for HPAM/XG *** to 200 wppm HPAM solution,addition of XG did not improve the drag reduction efficiency of HPAM/XG mixed solutions though XG slightly improved the resistance against mechanical degradation in HPAM/XG mixed polymer solutions.

关键词： Slickwater Polyacrylamide Xanthan gum Drag reduction shear stability

Synthesis of Polymethacrylates Used as Multifunctional Lubricating Oil Additives

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China Petroleum Processing & Petrochemical Technology 2015年第2期17卷 69-75页

作者： Liu Yinong Fan Lichuang Duan Qinghua SINOPEC Research Institute of Petroleum Processing

In this paper, four kinds of polymethacrylates(PMAs) used as multifunctional additives were synthesized from quaternary C1—C14 methacrylate, among which sample 4 exhibited relatively better performance. According to the methacrylate ratio of sample 4, the optimized reaction conditions of PMA were explored by orthogonal experiments comprising 4 factors and 3 levels, and the optimized reaction conditions covered an initiator dosage of 0.8 %, a molecular weight regulator dosage of 0.4%, a reaction temperature of 95 ℃ and a reaction time of 8.5 h. When the optimized PMA samples were used to formulate the 75W/90 automotive gear base oil, they exhibited improved shear stability and good low temperature property. In comparison with foreign commercial polymethacrylate GP, the optimized PMA samples exhibited better thickening ability, similar shear stability and slightly weak low temperature property, with their performance being the same as GP's on the whole. The slight difference in the performance between the optimized PMA and GP was attributed to the difference of chain length of copolymers and the distribution of relative molecular mass between them.

关键词： polymethacrylate thickening ability shear stability low temperature property