Asia-Pacific Journal of Chemical Engineering
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2013
·Vol. 9
·期 2
·248-255
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IF 0.797
Jianxian Zeng,Qiannan Guo,Zhenzhong Ou-Yang,Hu Zhou,Huajun Chen
Polyelectrolyte-enhanced ultrafiltration was investigated for the removal of chromium(VI) anion from aqueous solutions with the help of cationic polyquaternium-6 (PQ6). The ultrafiltration behavior of Cr(VI) aqueous solutions was studied at pH 6. Owing to an effect of electrostatic repulsion, the membrane with a molecular weight cutoff (MWCO) of 10 000 Da rejected about 30% of Cr(VI). Then, ultrafiltration of aqueous solutions of a Cr(VI)–PQ6 complex was further studied. Factors affecting Cr(VI) rejection coefficient ( R Cr ) and permeate flux ( J ) such as pH, polymer metal ratio (PMR), the added salts, temperature, operating pressure and MWCO were investigated. The best operating parameters, such as pH 9 and PMR 10, were obtained in order to achieve high R Cr (>0.97). By increasing the concentrations of the added salts (KCl, KNO 3 and K 2 SO 4 ), R Cr was found to decrease significantly. J decreases slightly in the pH range of 2–5. Cl − or SO 4 2− does not affect J , whereas NO 3 − results in the decrease of J . The binding mechanisms of dichromate, chromate and nitrate with PQ6 were proposed. Finally, the concentration experiment was carried out under the optimal conditions. R Cr was close to 1, and J decreases slightly. Chromium was effectively concentrated by the membrane. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.
研究领域:
环境科学
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化学工程
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DOI
高影响因子
CHEMOSPHERE
·
2023
·
IF 8.8
Jiaxuan Wang,Zhengxuan Ji,Peiru Fan,Jiaqi Duan,Jiaqing Xiong,Zhe Liu,Yushi Hou,Na Wang
Perfluorobutane sulfonic acid (PFBS) is a kind of anthropogenic recalcitrant contaminant that has posed a threat to drinking water safety and brought widespread public health concerns. Nanofiltration (NF) is an effective way to remove PFBS from drinking water, while the removal is influenced by coexisting ions. To investigate the effects and intrinsic mechanisms of coexisting ions on the rejection of PFBS, poly(piperazineamide) NF membrane was utilized in this work. Results showed that most cations and anions in the feedwater could effectively improve PFBS rejection and simultaneously reduce NF membrane permeability. In most cases, the decrease in NF membrane permeability corresponded to an increase in the valence of cations or anions. When cations (Na + , K + , Ca 2+ , and Mg 2+ ) were present, the rejection of PFBS was effectively improved from 79% to more than 91.07%. Under these conditions, electrostatic exclusion was the dominant NF rejection mechanism. This was also the leading mechanism for 0.1 mmol/L Fe 3+ coexisted condition. As the concentration of Fe 3+ increased to 0.5–1 mmol/L, intensified hydrolyzation would accelerate the formation of the cake layers. The differences in the cake layer characteristics led to the different rejection trends of PFBS. For anions (SO 4 2− and PO 4 3− ), both sieving effects and electrostatic exclusion were enhanced. As anionic concentration raised, the NF rejection of PFBS increased to above 90.15%. By contrast, the effect of Cl − on PFBS rejection was also affected by coexisting cations in the solution. The dominant NF rejection mechanism was electrostatic exclusion. Accordingly, it is suggested that the usage of negatively charged NF membranes could facilitate the efficient separation of PFBS under ionic coexisting conditions, thereby ensuring the safety of drinking water.
研究领域:
环境科学
·
水处理工程
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2024
·
IF 8.4
Xin Mao,Nuanyuan Xu,Xinyu Shi,Hui Wen,Changkun Liu
Nanofiltration (NF) is commonly recognized as one of the effective technologies for the separation of magnesium (Mg 2+ ) and lithium (Li + ) from salt-lake brines. Charge repulsion and size exclusion effects often play an important role, whose functions primarily occur at the top surface and the matrix, respectively, of the skin layer. In this study, a novel nanofiltration (NF) membrane is prepared that integrates both size exclusion and charge repulsion effects into the matrix of the skin layer for enhanced Mg 2+ /Li + separation. With the surface-modified hydrophilic polyethylene (PE) membrane as the supporting layer, the prepared NF membrane successfully incorporated Fe 3+ ions into the matrix of the skin layer during the interfacial polymerization (IP). Fe 3+ ions which chelate with amine groups of PEI (aqueous-phase monomers during IP) ensure abundant positive charges within the matrix of the skin layer, providing good hydrophilicity and sustained electrostatic repulsive force against the transmembrane transport of Mg 2+ , and thus the enhanced rejection. Results exhibited a remarkable 92.6 % rejection rate for MgCl 2 and a higher water permeance of 22 LMH/bar, which is 1.57 times greater than that of the traditional PEI-TMC membranes. The nanofiltration process effectively reduced the Mg 2+ /Li + ratio from 50 in the feed to 5.4 in the permeate solution. It is also interesting to find that although the pore size of the skin layer (0.53 nm in radius) exceeds both the hydrated radii of Mg 2+ and Li + , the positive charges within the matrix of the skin layer still provide good selective separation performance, thus effectively breaking the trade-off of permeability and selectivity. This study offers a fresh perspective on the preparation of nanofiltration membranes by systematically exploring the potential of integration of charge repulsion and size exclusion effects into one location, i.e., the matrix of the skin layer for enhanced Mg 2+ /Li + separation performance.
研究领域:
材料科学
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环境工程
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产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2023
·Vol. 140
·期 23
·e53931
·
IF 3
Zhenzhong Li,Tianfeng Zhou,Hai Liu,Yu Jin,Yuxia Pang,Hongming Lou,Dongjie Yang,Xueqing Qiu
The steric hindrance formed by polyether side chains is the key factor determining the dispersion performance of polycarboxylate superplasticizer (PCE). While with the increase of the side chain length, the coiled conformation of side chain will prevent the dispersion ability of PCE from being further improved. In this work, the methallyl polyoxyethylene ether (HPEG) was esterified with tricarballylic acid (TA) to obtain dicarboxyl terminated macromonomer, and further used to synthesize polycarboxylate (PCETA). The fluidity tests show that compared with ordinary PCE-B2400 with short side chain, the dispersion performance of PCETA-2400 was slightly improved. While for the PCEs with long side chain, the dispersion ability of PCETA-4000 was significantly improved than that of ordinary PCE-B4000. The adsorption layer thickness of PCETA-4000 adsorbed on the surface of SiO 2 sphere measured by dynamic light scattering is 7.93 nm, which is 1.3 times that of PCE-B4000. Due to electrostatic repulsion between the carboxylic groups, the stretching of long side-chain forms stronger steric hindrance and enhancing the dispersion of cement particles. In addition, PCETA also shows good slump retention and clay resistance properties, and it is an excellent multi-functional concrete admixture with great application potential.
研究领域:
建筑材料化学
·
胶体化学
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产品关联
DOI
高影响因子
Bioactive Materials
·
2024
·
IF 18
Jingwen Liu,Liang Chen,Zhenyu Sun,Zaijin Tao,Volotovski Pavel,Yusheng Li,Fei Wang,Wenguo Cui,Shen Liu
Gene therapy is capable of efficiently regulating the expression of abnormal genes in diseased tissues and expected to be a therapeutic option for refractory diseases. However, unidirectional targeting gene therapy is always desired at the tissue interface. In this study, inspired by the principle that like charges repulse each other, a positively charged micro-nano electrospun fibrous membrane with dual-layer structure was developed by electrospinning technology to achieve unidirectional delivery of siRNA-loaded cationic nanocarriers, thus realizing unidirectional gene therapy at the tendon-paratenon interface. Under the charge repulsion of positively charged layer, more cationic COX-2 siRNA nanocarriers were enriched in peritendinous tissue, which not only improved the bioavailability of the gene drug to prevent the peritendinous adhesion formation, but also avoided adverse effects on the fragile endogenous healing of tendon itself. In summary, this study provides an innovative strategy for unidirectional targeting gene therapy of tissue interface diseases by utilizing charge repulsion to facilitate unidirectional delivery of gene drugs.
研究领域:
生物医学工程
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组织工程
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基因治疗
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DOI
PubMed
高影响因子
Polymers
·
2025
·Vol. 17
·期 8
·1065
·
IF 4.9
Qing Yang,Haiyang Yu,Xiaolu Wang,Yunze Li,Dan Li,Fu Guo
New 3D printing aerogel materials are environmentally friendly and could be used in environmental protection and biomedical fields. There is significant research interest in 3D printing cellulose-based aerogels since cellulose materials are biocompatible and are abundant in nature. The gel-like nature of the cellulose water suspension is suitable for 3D printing; however, the complexity and resolution of the geometry of aerogels are quite limited, mainly due to the inks’ low viscosity that fails to maintain the integrity of the shape after printing. To address this limitation, a carefully optimized formulation incorporating three key ingredients, i.e., nanofibrils (TEMPO-CNFs), 2,2,6,6-tetramethyl-1-piperidinyloxy modified cellulose nanocrystals (TEMPO-CNC), and sodium carboxymethyl cellulose (CMC), is utilized to enhance the viscosity and structural stability of the ink. This combination of cellulose derivatives utilizes the electrostatic repulsive forces between the negatively charged components to form a stable and uniformly distributed suspension of cellulose materials. Our ink formulations improve printability and shape retention during 3D printing and are optimal for DIW printing. We print by employing an all cellulose-based composite ink using a modified direct ink writing (DIW) 3D printing method, plus an in situ freezing stage to form a layer-by-layer structure, and then follow a freeze-drying process to obtain the well-aligned aerogels. We have investigated the rheological properties of the ink formulation by varying the concentration of these three cellulose materials. The obtained aerogels exhibit highly ordered microstructures in which the micropores are well-aligned along the freezing direction. This study demonstrates a strategy for overcoming the challenges of 3D printing cellulose-based aerogels by formulating a stable composite ink, optimizing its rheological properties, and employing a modified DIW printing process with in situ freezing, resulting in highly ordered, structurally robust aerogels with aligned microporous architectures.
研究领域:
材料科学
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环境科学
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生物医学工程
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产品关联
DOI
PubMed
高影响因子
ENERGY & FUELS
·
2025
·
IF 5.3
Zhe Wang,Han Jia,Qiuxia Wang,Ruitong Xu,Haowen Yu,Zhenghao Kou,Yihan Huang,Bowen Wang,Xu Li
Nowadays, novel silicon quantum dots (SiQDs) are applied in various aspects of the petroleum industry, especially in enhanced oil recovery (EOR). Herein, amphiphilic silicon quantum dots (ASiQDs) were synthesized to improve the stability of the foam formed by the nonionic surfactant polyethylene glycol monoisodecyl ether (PMIE). The greater stability and oil resistance of foam stabilized by the 0.05% PMIE-0.1% ASiQD system compared to other systems (including pure PMIE systems and conventional silica nanoparticles (SiNPs)–PMIE systems) were confirmed by relative foam volume measurement, half-life measurement, Turbiscan Laboratories expert analysis, and the observation of foam morphology. Based on the dynamic surface tension and modulus measurements, the promising stability of the foam was attributed to the rigid film generated by largely adsorbed ASiQDs with tiny size and moderate hydrophobicity. the more intensive electrostatic repulsion among ASiQDs stabilized smaller foam bubbles, significantly preventing coalescence. Finally, the sandpack flooding results suggested 0.05% PMIE-0.1%ASiQD system stabilized foam could efficiently plug the high permeability pore throats and evidently enhanced the oil recovery by 21.2%. The report employed the novel ASiQDs stabilized foam to improve the flooding efficiency for EOR.
研究领域:
石油工程
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材料科学
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化学工程
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DOI
高影响因子
RSC Advances
·
2025
·Vol. 15
·期 16
·12528-12537
·
IF 4.6
Junbo Wang,Jie Jiang,Jing Wang,Shouyuan Hu,Jiahao Hu,Yalong Li,Zhiyu Tao,Chengju Wu,Pei Li,Liang Chen
Nanofiltration has emerged as an effective technique for the selective separation of mono- and divalent ions, such as Mg2+/Li+ mixtures, and plays a crucial role in lithium extraction from salt lakes. In this study, a graphene oxide (GO) membrane with positively charged channels was prepared by crosslinking arginine (Arg) onto GO nanosheets, followed by vacuum filtration to form the membrane, and then thermal reduction (Arg-rGO). The Arg-rGO membrane exhibits high performance in the ion separation of a typical brine with a Mg2+/Li+ mass ratio of 20. The separation factor (SLi/Mg) reached up to 45.6—two times the highest separation factor reported—while maintaining an advanced water permeance of 21.3 L m−2 h−1 bar−1. Furthermore, the Mg2+/Li+ mass ratio was reduced from 20 to 0.2 after two-stage crossflow filtration with high flux under high pressure. The observed separation performance can be attributed to the synergistic effect of electrostatic repulsion and size-exclusion. These findings confirmed efficient separation of Mg2+/Li+ using GO membranes, demonstrating potential for practical application in lithium extraction from salt lakes.
研究领域:
材料科学
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环境工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
WATER RESEARCH
·
2024
·
IF 11.4
Yunkai Sun,Wanting Sun,Yude Li,Nannan Dong,Haiyan Yu,Weiyan Yin,Fanping Zhu,Baoyu Gao,Shiping Xu
The ubiquitous chloride ions (Cl − ) in water seriously interfere with pollutant oxidation and inevitably generate undesirable chlorinated byproducts. In this study, we report for the first time that a negatively charged molecularly imprinted photocatalyst (MIP) can effectively inhibit Cl − interference and suppress the production of chlorination byproducts (the yield of chloroacetic acid was only 16 % of the bare photocatalyst system) while ensuring efficient degradation of target pollutants, thereby greatly improving the safety of the pollutant degradation process. Taking antibiotics as target pollutant, we investigated the mechanism of action of MIP by comparing the antibiotic degradation pathways, fate of photogenerated active species and production of reactive chlorine species (RCS) in the MIP and bare photocatalyst system. The mechanism by which MIP inhibits Cl − interference was mainly based on a synergy between electrostatic repulsion and steric hindrance induced by the specific capture of antibiotics in imprinted cavity, which effectively suppressed the production of RCS and hindered the participation of RCS in antibiotics degradation. In addition, MIP showed good compatibility with common cations, anions and organic matter, and performed well within a broad pH range in various water environments. Thus, the negatively charged MIP provides a feasible approach for the safe and efficient removal of pollutants in Cl − containing water.
研究领域:
环境科学
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化学工程
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
·
2015
·
IF 3.615
Yong-Qi Li,Peng Wang,Heng Zhang,Xiao-Li Zhao,Yong Lu,Zora Popović,Ye Liu
The neutral diphosphine of 1 and the corresponding ionic diphosphine of 2 after quaternization 1 by MeOTf were prepared and investigated as the wide bite angle and bulky steric ligands to control the regioselectivity in Rh(acac)(CO) 2 -catalyzed hydroformylation of 1-octene. As for 2 , due to the electrostatic repulsive force of the two positive charges, the involved two-PPh 2 were located in trans -position with the relatively longer P 1… P 2 distance [8.0231(11) Å] to prefer to aa-site coordination in trigonal bipyramid H(alkene)Rh(CO)(P–P) intermediate, which renders less bulky steric hindrance for the regioselectivity to linear aldehyde as a result of low L / B ratio of 1.9. Due to the strong electron-withdrawing effect from the positive-charged imidazolium rings on the neighbored P-atoms, 2 with strong π-acceptor ability can develop π-backdonation interaction between Rh and P linkage to favor the dissociation of CO ligand and facilitate the selectivity to nonanals. In contrast, 1 with no electrostatic repulsive effect and less steric hindrance, the two-PPh 2 were able to be conveniently located in cis -position with the relatively shorter P 1… P 2 distance [ P 1… P 2, 6.2096(10) Å], which corresponded to the preferential linear regioselectivity with L / B = 7.1. The in situ high pressure spectroscopy analysis indicated that the involvement of 1 in Rh(acac)(CO) 2 -catalyzed hydroformylation of 1-octene could greatly facilitate the formation and stability of the active Rh–H species ( ν 2047 cm −1 ).
研究领域:
有机化学
·
催化化学
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DOI
高影响因子
危险品化学品经营许可证（带存储）