SCIENCE OF THE TOTAL ENVIRONMENT
·
2022
·
IF 10.753
Zhenxiang Pan,Bizhen Zeng,Genying Yu,Hongjun Lin,Lijiang Hu,Jiaheng Teng,Hanmin Zhang,Lining Yang
While ethylenediamine tetramethylenephosphonic acid (EDTMPA) has been emerged as a stronger chelating agent than ethylene diamine tetraacetic acid (EDTA) for fouling mitigation, and transparent exopolymer particles (TEP) is a major foulant in membrane-based water treatment process, effects of EDTMPA on TEP fouling and the underlying mechanism have been not yet studied. In this study, Flory-Huggins lattice theory was combined with density functional theory (DFT) technology to explore this subject at molecular level. Filtration experiments showed a unimodal pattern of specific filtration resistance (SFR) of TEP sample with Ca 2+ concentration in range of 0–3 mM. For the TEP sample with the peak SFR value at 1.5 mM Ca 2+ , continuous addition of EDTMPA (from 0 to 100 mg·L −1 ) resulted in a sustained decrease in SFR. Energy dispersive spectroscopy (EDS) mapping characterization showed the continuing decline of calcium content in the TEP layer with increase of EDTMPA addition, indicating that EDTMPA successfully captured Ca 2+ from alginate‑calcium ligation (TEP), and then disintegrated the TEP structure. DFT simulation showed that Ca 2+ preferentially coordinated with the terminal carboxyl groups of alginate chains to form a coordination configuration that is conducive to stretch the three-dimensional polymer network. Such a network corresponded to an extremely high SFR according to Flory-Huggins theory. EDTMPA addition caused disintegration of the coordination configuration of Ca 2+ binding to terminal carboxyl groups, which further resulted in collapse and flocculation of TEP gel network structure, thus leading to a continuous SFR decrease. This work provided deep thermodynamic insights into effects of EDTMPA on TEP-associated fouling at molecular level, facilitating to better understanding and mitigation of membrane fouling.
研究领域:
环境科学
·
分子生物学
✓ 已验证
DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2022
·
IF 10.753
Zhenxiang Pan,Bizhen Zeng,Hongjun Lin,Jiaheng Teng,Hanmin Zhang,Huachang Hong,Meijia Zhang
While transparent exopolymer particles (TEP) has high fouling potential, its underlying fouling mechanisms have not yet been well revealed. In current work, fouling characteristics of TEP under different Ca 2+ concentrations (0 to 1.5 mM) were investigated. TEP quantification and filtration tests showed that TEP contents increased with Ca 2+ concentration, while TEP's specific filtration resistance (SFR) under the influence of Ca 2+ concentration presented a unimodal pattern. The peak of TEP's SFR reached at Ca 2+ concentration of 1 mM when SA concentration was 0.3 g·L −1 . A series of characterizations suggested that microstructure transformation of TEP particles was the main contributor to the resistance variations of TEP solution. The optical microscope observation showed that above and below the critical Ca 2+ concentration (1 mM when SA concentration is 0.3 g·L −1 in this study), the formed TEP existed in the form of c-TEP (average particle size is 0.24 μm) and p-TEP (average particle size is 1.05 μm), respectively. Thermodynamic analysis showed that the adhesion ability of c-TEP (−249,989 and − 303,692 kT) was more than 19 times than that of p-TEP (−12,905 kT), which would accelerate foulant layer formation. In addition, below the critical value, the increased SFR with Ca 2+ concentration could be explained by integrating Flory-Huggins lattice theory with the preferential intermolecular coordination. Above the critical value, the decreased SFR can be attributed to the formation of a “large-size crack structure” cake layer from the p-TEP. This study revealed fundamental mechanisms of membrane fouling caused by TEP, greatly deepening understanding of TEP fouling, and facilitating to development of effective fouling control strategies.
研究领域:
环境科学
·
水处理
·
膜技术
·
热力学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Environmental Sciences
·
2015
·
IF 2.002
Dandan Cheng,Yue Liu,Haiqiang Wang,Xiaole Weng,Zhongbiao Wu
In this study, a series of polyetherimide/SBA-15: 2-D hexagonal P6mm, Santa Barbara USA (PEI/SBA-15) adsorbents modified by phosphoric ester based surfactants (including tri(2-ethylhexyl) phosphate (TEP), bis(2-ethylhexyl) phosphate (BEP) and trimethyl phosphonoacetate (TMPA)) were prepared for CO 2 adsorption. Experimental results indicated that the addition of TEP and BEP had positive effects on CO 2 adsorption capacity over PEI/SBA-15. In particular, the CO 2 adsorption amount could be improved by around 20% for 45PEI–5TEP/SBA-15 compared to the additive-free adsorbent. This could be attributed to the decrease of CO 2 diffusion resistance in the PEI bulk network due to the interactions between TEP and loaded PEI molecules, which was further confirmed by adsorption kinetics results. In addition, it was also found that the cyclic performance of the TEP-modified adsorbent was better than the surfactant-free one. This could be due to two main reasons, based on the results of in situ DRIFT and TG-DSC tests. First and more importantly, adsorbed CO 2 species could be desorbed more rapidly over TEP-modified adsorbent during the thermal desorption process. Furthermore, the enhanced thermal stability after TEP addition ensured lower degradation of amine groups during adsorption/desorption cycles.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Junsen Zhong,Bingkun Huang,Jianxin Song,Xiaolong Zhang,Lingyu Du,Yanfeng Gao,Wei Liu,Litao Kang
As the best-known and extensively-studied electrochromic material, tungsten trioxide (WO 3 ) has drawn tremendous interest due to its low material cost, environmental benignity, dual band regulation, high optical modulation, and high chemical stability. However, these films always suffer from ion-trapping-induced degradation in electrochromic performance when cycled in alkali cation (such as Li + , Na + , K + , etc.) electrolytes. Herein, we report a stable WO 3 electrochromic system enabled by a NH 4 CF 3 SO 3 -TEP (Triethyl phosphate) organic electrolyte. Based on comparative experiments and systematic characterizations, the prolonged cycling stability is mainly attributed to the formation of hydrogen bonds between the NH 4 + ions and the WO 3 lattice, which are much weaker than metallic coordination bonds. Furthermore, the bulky CF 3 SO 3 − anion and large TEP solvent molecule are also favorable to stabilize WO 3 , since they are more resistive to be co-inserted into the WO 3 lattice along with the shuttling NH 4 + cations. Thanks to these merits, this NH 4 CF 3 SO 3 -TEP electrolyte simultaneously enables great electrochromic activity (76.1 % transmittance modulating ability at 633 nm) and impressive cyclic color-switching stability (1000 times color change without any detectable electrochromic performance or mechanical degradation), overwhelmingly outperforming the conventional Li + /K + electrolytes. Furthermore, as a demonstration of its application, a WO 3 /Zn electrochromic device is fabricated based on a NH 4 + /Zn 2+ -CF 3 SO 3 dual-cation TEP electrolyte. These findings may shed light on the in-depth understanding of WO 3 ′s “ion trapping” effect, as well as the electrolyte design of high-performance WO 3 -based electrochromic devices.
研究领域:
材料科学
·
电化学
·
光电
✓ 已验证
产品关联
DOI
高影响因子
Journal of Water Process Engineering
·
2023
·
IF 7
Zhaohui Zhang,Tong Zhang,Liang Wang,Mengmeng Chen,Bin Zhao,Junjing Li,Cong Ma,Xiuru Chu,Pengda Zhang
Free transparent exopolymer particles (TEP) are an important type of TEP. Researchers have recognized the significant contribution of free TEP to irreversible membrane fouling when treating algae-laden water. Constructing a reasonable process to effectively decelerate membrane fouling caused by free TEP is necessary for the ultrafiltration of algae-laden water. Our experiments indicate that the integrated process of magnetic anion exchange resin (MIEX)/ultrafiltration (UF) can effectively impede the irreversible membrane fouling caused by free TEP. Compared with independent UF, after multi-cycle filtration, the growth rate of hydraulically and chemically irreversible fouling decreased by 40 % and 21 %, respectively, during the MIEX/UF process. The interfacial forces between free TEP and polyvinylidene fluoride (PVDF)/MIEX were determined using atomic force microscopy , and the results showed that the interfacial force of MIEX–free TEP was 4.3-fold higher than that of PVDF–free TEP. Although the adsorption of free TEP by MIEX partly reduced membrane fouling during the MIEX/UF process, the MIEX dynamic layer contributed the most to the alleviation of irreversible membrane fouling during MIEX/UF. Our experimental results provide a more feasible process design for effectively controlling the TEP-induced irreversible membrane fouling.
研究领域:
环境科学
·
水处理工程
✓ 已验证
DOI
高影响因子
Advanced Science
·
2021
·Vol. 8
·期 15
·2003241
·
IF 16.806
Shengzhao Zhang,Taibo Liang,Donghuang Wang,Yanjun Xu,Yongliang Cui,Jingru Li,Xiuli Wang,Xinhui Xia,Changdong Gu,Jiangping Tu
An elastic and safe electrolyte is demanded for flexible batteries. Herein, a stretchable solid electrolyte comprised of crosslinked elastic polymer matrix, poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP), and flameproof triethyl phosphate (TEP) is fabricated, which exhibits ultrahigh elongation of 450%, nonflammability and ionic conductivity above 1 mS cm −1 . In addition, in order to improve the interface compatibility between the electrolyte and Li anode and stabilize the solid-electrolyte interphase (SEI), a protecting layer containing poly(ethylene oxide) (PEO) is designed to effectively prevent the anode from reacting with TEP and optimize the chemical composition in SEI, leading to a tougher and more stable SEI on the anode. The LiFePO 4 /Li cells employing this double-layer electrolyte exhibit an 85.0% capacity retention after 300 cycles at 1 C. Moreover, a flexible battery based on this solid electrolyte is fabricated, which can work in stretched, folded, and twisted conditions. This design of a stretchable double-layer solid electrolyte provides a new concept for safe and flexible solid-state batteries.
研究领域:
材料科学
·
电化学
·
储能技术
·
高分子科学
·
锂电池
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）