INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2018
·
IF 3.141
Yang Yu,Huachang Jin,Xindi Jin,Runxin Yan,Li Zhang,Xueming Chen
Electrochemical precipitation has obtained great attentions for water softening in recent years. In order to avoid cathode deactivation, periodical scale detachment is essential. In general, the scale adhered to the cathode is detached by mechanical scraping. Although mechanical scraping is easy operated, elastic scraper must be installed between electrodes, leading to the low softening efficiency and high energy consumption. To overcome such a problem, a new current pulsated electrochemical precipitation process was proposed in this paper. Scale detachment was accomplished by increasing the current density significantly. Experimental results showed that the both high softening and detachment performance were achieved. The precipitation rate was as high as 40.47 g/h/m2. The energy consumption and the total hardness removal efficiency were 8.9–13.2 kWh/kg CaCO3 and 17.8–22.8%, respectively. Repetitive experimental results indicated the current pulsated electrochemical precipitation process could run steadily without any performance decay detected after repetitive operation.
研究领域:
环境科学
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水处理工程
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产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2023
·
IF 8.2
Qianqian Tang,Hao Wu,Mingsong Zhou,Dongjie Yang
Presently, most studies on modified lignin focused on the adsorption to heavy metal cations, but rarely to Ca 2+ in hard water . Therefore, this work prepared a new gel-type lignin-based cationic adsorption resin (E-LSAF) through the crosslinking and curing of alkali lignin grafted by sodium sulfite sulfonated acetone to remove Ca 2+ in water. Under the determined optimum synthesis conditions, E-LSAF with a highest sulfonic group content of 1.99 mmol/g was obtained. Structural and physicochemical measuring results showed E-LSAF was a gel-type resin, owning strong hydrophilicity , high mechanical strength, excellent thermal stability and acid-alkaline resistance. Adsorption results indicated the adsorption of E-LSAF to Ca 2+ was well-fitted by Langmuir model, and the maximum adsorption capacity reached 45.8 mg/g. Pseudo-second-order model can describe this adsorption process well, suggesting it a chemisorption process. Dynamic column adsorption results showed E-LSAF could transform hard water into soft or even very soft water. The regeneration efficiency still maintained 80 % after 5 cycles. The adsorption mechanism was attributed to electrostatic attraction, ion exchange and complexation. This work provided a high-performance lignin-based cationic adsorption material with high adsorption capacity to Ca 2+ and excellent acid-alkaline resistance, which filled the research gap of using modified sulfonated lignin to remove Ca 2+ from water.
研究领域:
材料科学
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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
RSC Advances
·
2016
·Vol. 6
·期 96
·93947-93955
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IF 3.289
Bin Dong,Ying Xu,Danni Shen,Xiaohu Dai,Senming Lin
Reusing wastewater can enormously reduce environmental pollution and save water. One of the key obstacles to reuse is the scaling caused by calcium (Ca) ions and humic matter (HM). The interactions among HM, Ca ions and cation-exchange resins (CERs) during the water softening process were explored via lab-scale and pilot-scale tests. Surface topography, pore structure, and surface molecular structure of the CERs were determined using an atomic-force microscope, an automatic mercury porosimeter, a laser-Raman spectrum and X-ray photoelectron spectroscopy, respectively. The surface charge of CERs was assessed by measuring zeta potential. Experimental results showed that HM can react with Ca-ions to form HM–Ca+ and Ca ions can act as a bridge for HM and CER, suggesting that Ca ions and HM can be simultaneously removed by CERs. Kinetic analyses indicate that a pseudo-first order equation was able to accurately describe the overall adsorption kinetics and diffusion of Ca ions through a liquid film of CER was the rate-determining step for the overall adsorption process. Further investigation revealed that during the first 60 minutes of adsorption, the effect of HM on the CER adsorption kinetics can be described well by pseudo-first and pseudo-second order equations. This indicates that diffusions of Ca ions, HM, and HM–Ca+ and their interactions were equivalent for controlling the initial stage of adsorption. In addition, 99% of Ca ions and 30–60% of HM in wastewater were removed in the pilot-scale test, suggesting that CERs have significant potential to remove Ca ions and HM simultaneously in wastewater.
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
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2019
·
IF 7.015
Huachang Jin,Yang Yu,Xueming Chen
Electrochemical precipitation has been widely employed for recirculating cooling water softening because of its environmental friendliness, convenient operation, and high treatment efficiency. However, this technique uses many expensive electrodes, and thus requires a very large investment. In this study, a novel process called membrane-based electrochemical precipitation (MEP) was proposed and tested for water softening. This new process utilises membrane polarisation, an undesirable phenomenon that occurs in conventional electrodialysis , to precipitate hardness ions on the surface of membranes. Compared with conventional electrodialysis , MEP involves only one kind of exchange membrane . Moreover, unlike traditional electrochemical precipitation, MEP only needs one pair of electrodes, and thus can reduce equipment cost significantly. Different types of membranes were examined, and heterogeneous anion exchange membranes were found to be the best. It was demonstrated that MEP could soften water effectively. The precipitation rate and energy consumption were 64.0–84.6 g/h/m 2 and 8.8–12.0 kW h/kg CaCO 3 , respectively. The scale deposited on the membranes could be detached easily through polarity reversal of electrodes. Repeated experiments showed that MEP could run stably without any performance deterioration .
研究领域:
环境科学
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化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2024
·
IF 8.4
Tong Sun,Ziran Zhu,Zelin Qiu,Wushang Yang,Yani Jiang,Qianwei Su,Liheng Zhu,Zihao Zhao,Xiaojun Huang,Yunyun Xue,Jiacheng Qian,Baoku Zhu
To obtain positively charged layer and achieve high divalent cation rejection, a novel nanofiltration (NF) membrane was successfully fabricated by utilizing polyethyleneimine (PEI), newly fabricated polyacrolein (PA) and amine silane coupling agent γ-aminopropyl triethoxysilane (APTES). The PA was synthesized via radical polymerization to avoid the migration and volatilization of small molecule in the typical coating process, making NF membranes even with great stability. On the one hand, the PEI crosslinked with PA through Schiff base reaction; on the other hand, the in-situ hydrolysis self-polycondensation of APTES generated loose networks with Si–O–Si bonds which provided the permeation channel for water and accordingly boosted the water permeance. The water permeance of the optimal PEI/PA/APTES membrane could reach 16.9 L m −2 h −1 ·bar −1 and the Mg 2+ and Ca 2+ rejections were 98.8 % and 97.3 %, respectively, better than those of commercial NF membranes, breaking up the “trade off” effect. This study prepared a high-performance PEI/PA/APTES hybrid NF membrane oriented for hard water softening in tap water and brackish water via the non-interfacial macromolecule crosslinking coating method.
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
CHEMOSPHERE
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2022
·
IF 8.943
Zhongbao Ma,Long-Fei Ren,Diwen Ying,Jinping Jia,Jiahui Shao
The separation of hardness ions such as calcium and magnesium from hard water can improve water quality, which is important but technically challenging. Nanofiltration (NF) has attracted much attention because of its efficiency, environmental friendliness and low cost. However, common NF membranes with a singly (either positively or negatively) charged layer have insufficient water softening capacity. In this work, two types of dual-layer Janus charged polyamide NF membranes composed of oppositely charged inner and outer layers were developed for the first time by sequential electrospray polymerization strategy for efficient water softening. The effect of the microstructure of the dually charged barrier layer on the separation performance of divalent salt ions was explored. Detailed mechanistic studies revealed that the microstructure of the outer layer of the barrier layer played a crucial role in the ion separation of the Janus membrane due to its control of the reverse transport of ions. Janus charged polyamide NF membrane with a loose outer layer exhibited better water softening performance (93.6% of hardness removed) compared to the singly charged NF membranes due to the simultaneous dual electrostatic effect and no ion reverse transport confinement. This Janus charged NF membrane also possessed good antifouling performance, mainly due to its negatively charged outer layers. The mechanistic insights gained in this study reveal the huge potential of microstructural design toward high-performance Janus charged NF membranes, and provide important guidance on the future development of high-efficiency water softening NF membranes.
研究领域:
材料科学
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环境工程
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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 Environmental Chemical Engineering
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2025
·
IF 7.2
Junwei Wang,Xuhui Wang,Dengjia Yuan,Min Xu,Ziyu Yan,Honghua Ge
The electrochemical water softening technique has the advantages of environmental friendliness, energy saving, and no secondary pollution. However, the easy scaling on the cathode surface affects its hardness removal efficiency, especially for slag-flushing water with high hardness and low alkalinity. In addition, the impact of electrochemically softened water on metal corrosion behavior is unclear and poses potential safety hazards. In this study, a novel electrochemical water softening reactor with a barrier layer structure was designed. By increasing the pH value of the water solution in the cathode region, the precipitation reaction was transferred from the cathode surface to the solution and barrier layer surfaces. The strong oxidizing substances generated by the anodic reaction were adsorbed through the barrier layer, thereby inhibiting their corrosive effect on carbon steel. Compared with the common electrochemical water softening reactor, the improved reactor has increased the pH in the cathode region from 8.58 to 12, increased the hardness removal efficiency from 5.8 % to 53.6 %, and reduced the corrosion rate of carbon steel from 0.396 mm/a to 0.254 mm/a. The significant increase in pH accelerated the rate of precipitation reactions in solution, increased the particle size of the precipitate, and caused rapid settling of the precipitate particles. The average settling rate of precipitated particles was 0.331 mg/s, much higher than the 0.017 mg/s before the improvement. Meanwhile, the strong oxidizing ions of ClO - were effectively adsorbed by the activated carbon plate, which in turn slowed down the corrosion of carbon steel by electrochemical water softening.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2025
·
IF 9
Linghui Wang,Dan Qiu,Yichi Zha,Yanping Zhang,Zhongchun Yuan,Fan Hu,Hongxing Liu,Dan Qiu
With the rapid development of fine chemical industries and electronics manufacturing industries, a large amount of wastewater containing endocrine disrupters, antibiotics, dyes and heavy metal ions have been discharged into the environment, threatening the safety of drinking water. In this work, polyethyleneimine-polyethersulfone (PEI-PES) copolymer was synthesized via the chain exchange reaction, then blended with polyethersulfone (PES) for the fabrication of polyethyleneimine functionalized polyethersulfone (PEI-PES/PES) membranes via phase separation process. The as-prepared membranes can efficiently remove multiple pollutants from water through the dual mechanism of filtration and surface adsorption of the PEI segments. The membranes are hydrophilic and positively charged, therefore they had well perm-selectivity. Especially, the PEI-PES/PES membrane with PEI loading of 30 wt% in polymers (namely M30) exhibited a good monovalent and divalent ion selectivity with a CaCl 2 rejection of 78.0 % and NaCl rejection of 38.3 % at a water flux of 181 L·m −2 ·h −1 , owing to the sieving effect and the Donnan exclusion. In addition, the adsorption kinetics of the as-prepared membranes toward bisphenol A (BPA), tetracycline (Tc), sunset yellow (SY), and copper ion (Cu 2+ ) followed a pseudo-second-order model. The corresponding equilibrium adsorption amount of M30 was 8.9, 7.1, 127.6 and 21.9 mg·g −1 , respectively. The adsorption performance was almost unaffected by salt and well recycled. The prepared PEI-PES/PES membranes demonstrated significant application potential in saline softening and security guarantee of drinking water.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
RSC Advances
·
2018
·Vol. 8
·期 25
·13656-13663
·
IF 2.936
Yangyang Wei,Jian Wang,Hao Li,Man Zhao,Huifeng Zhang,Yipeng Guan,Hai Huang,Baoxia Mi,Yushan Zhang
A tremendous quantity of brackish water with a high proportion of divalent cations is in great need of water softening. Layer-stacked graphene oxide membranes show potential in membrane processing due to their molecular sieving properties, but show poor selective retention of cations due to unstable interlayer spacing and electrostatic interaction. In this study, a partially reduced graphene oxide (prGO) and chitosan (CS) nanohybrid membrane (prGO–CS) was fabricated to achieve the selective retention of divalent cations by adjusting the configuration and controlling the surface charge. The prGO–CS membrane, which included a CS skin and embedded prGO sheets, showed a performance boost of 98.0% rejection of Mg2+ and 95.5% rejection of Ca2+ when compared with a CS membrane. The membrane showed good water softening performance for brackish water under low operation pressure with a high Na+/Mg2+ selectivity of 33.8. The excellent performance was attributed to the dense structure and positive charge of prGO–CS.
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
JOURNAL OF MEMBRANE SCIENCE
·
2015
·
IF 5.056
Jia Xu,Lili Zhang,Xueli Gao,Haiyan Bie,Yunpeng Fu,Congjie Gao
In this study, a facile and novel strategy for constructing tunable antimicrobial NF membrane surface was developed by a simple electrostatic assembly of polycation–copper(II) complex on the polyacrylonitrile substrate surface followed by cross-linking. Polycation–copper(II) complex with high stability and charge density, using polyethyleneimine (PEI) as a capping ligand, was formed by exquisitely manipulating the pH and Cu 2+ concentration for strong assembly on the surface. We confirmed that PEI–copper(II) complex assembly was a good way to significantly improve the Cu 2+ loading efficiency in terms of loading time and loading amount with AAS and EDS measurements. We also demonstrated that cross-linking had a significant influence not only on the strong assembly of PEI–Cu(II) complex to the substrate surface but also on the controllable Cu 2+ release, which was confirmed by SEM, EDS and AAS measurements after exposing the NF membrane to bath sonication and real seawater. The NF membrane exhibited significant antimicrobial activity with antibacterial efficiency of more than 95% and prevented effectively the formation of biofilms for up to 6-month test. For real seawater softening, the NF membrane achieved approximately 32.3 L/m 2 h flux and 43.5%, 68.3%, 98.1%, 19.1% and 18.7% rejection of salt, SO 4 2− , Mg 2+ , Na + and Cl − , respectively, with a high softening efficiency (low S value) compared to other commercial NF membranes. We hope that the present method can be developed as a competitive technology for the fabrication of robust and versatile antimicrobial membrane, leading to the high efficiency of seawater softening.
研究领域:
环境科学
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材料科学
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生物学
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产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2025
·
IF 7.2
Xuesong Chen,Lida Wang,Hejin Li,Zhongqiang Yu,Wen Sun,Zhengqing Yang,Haitao Deng,Qian Wang,Junhai Luo,Guichang Liu
The combination of scale inhibitor and electrochemical water softening technique is a novel strategy for effective scale inhibition, but selecting the appropriate scale inhibitor remains a challenge. In the work, a novel environmentally friendly scale inhibitor (PL 0.3 ) based on polyepoxysuccinic acid and lysine were synthesized using the dehydration condensation method to complement the electrochemical water softening technique. The compatibility of scale inhibitor and electrochemical water softening (SI/EWS) technique was evaluated by static experiments. The results indicated that SI/EWS can effectively remove scale-forming ions, achieving a precipitation rate of 14.27 g/m²·h at 24 A·m −2 when the PL 0.3 concentration is 6 mg·L −1 . Under these conditions, PL 0.3 remains highly stable in the electrochemical environment, with its scale inhibition performance unaffected the electric field and electrode reactions, achieving an inhibition efficiency exceeding 93 %. The dynamic experiment further demonstrated that SI/EWS technique can effectively inhibit scale. In addition, experiments and molecular dynamics simulations jointly demonstrated that the two unique properties of the weak ability to interfere with crystal nucleation of PL 0.3 around the cathode and its electrostatic repulsion with the cathode are the key factors for the combined scale inhibition of the SI/EWS. This study offers a novel perspective for achieving efficient scale inhibition in circulating cooling water systems.
研究领域:
环境工程
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材料科学
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化学工程
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Pengfei Li,Hongling Lan,Kuo Chen,Xiupeng Ma,Bingxin Wei,Ming Wang,Peng Li,Yingfei Hou,Q. Jason Niu
The toxic heavy metals produced by the discharge of industrial wastewater pose a serious threat to the ecological environment and human health. Nanofiltration (NF) membrane separation technology is widely used in fields such as water softening, heavy metal removal and dye separation due to its environmental friendliness and low cost. Herein, a novel positively charged aliphatic polyamide NF membrane (PEI-BTC) has been developed by using 1,2,3,4-cyclobutane tetracarboxylic acid chloride (BTC) monomer bearing a stereoscopic structure which undergoes classic interfacial polymerization (IP) with polyethyleneimine (PEI) on the Polyether sulfone (PES) support membrane. The physicochemical properties revealed that the PEI-BTC membrane had a larger mean effective pore size (0.285 nm), a thinner separation layer (40 nm) and a stronger positively charged membrane surface (IEP = 7.25) than the traditional PEI-TMC membrane. Compared with previously reported PEI-based and commercial NF membranes, the optimized PEI-BTC membrane exhibits a higher MgCl 2 (2000 ppm) rejection of 97.53% and pure water flux of 156.85 kg·m −2 ·h −1 at 1.0 MPa. Moreover, the prepared PEI-BTC NF membrane shows excellent toxic heavy metal (1000 ppm) removal efficiency in the order of Mn (98.78%) > Zn (98.32%) > Ni (97.74%) > Cu (95.67%) > Cd (90.49%). The results demonstrate that the prepared positively charged aliphatic polyamide NF membrane (PEI-BTC) has a unique industrial production potential for water softening and heavy metal removal.
研究领域:
环境科学
·
材料科学
·
水处理
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）