DESALINATION
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2016
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IF 4.412
Pengli Chen,Xiao Ma,Zhaoxiang Zhong,Feng Zhang,Weihong Xing,Yiqun Fan
Removing mixture salts from dye solutions using membrane technology still need to be improved for high dye rejection and low salt rejection. In this work, ceramic membrane with pore size of 1.5 nm presented a satisfactory desalination of dye solutions containing NaCl and Na 2 SO 4 compared with two commercial organic nanofiltration membrane elements (DK and DL). Effect of salt content, salt type, molar ratio of NaCl and Na 2 SO 4 , dye concentration and pH on performance of ceramic membrane for desalination of Eriochrome black T (EBT) were investigated. The results showed that dye rejection decreased by increasing salt content, dye concentration and solution pH. Compared with dye-NaCl solutions, a relative high flux and low rejection of dye were observed when treating dye-Na 2 SO 4 solutions. For the mixture salt-dye solutions, the flux, which was higher than that for the single salt-dye solutions, first increased then decreased with decreasing C NaCl /C Na2SO4 due to the change of structure of cake layer. Supper-molecule aggregates of EBT formed by hydrogen-bond is mainly responsible for the high rejection of EBT (> 99%) at acid conditions. The rejection of NaCl and Na 2 SO 4 was below 20% and 40%, respectively. These promising results demonstrates that the new ceramic membrane has a potential application in dye purification.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL PAPERS
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2025
·
IF 2.5
Chen Min,Liu Aimin,Kong Lingyu,Liu Fengguo,Li Song,Liu Yubao,Shi Zhongning
Graphene has been widely studied due to its unique structure and exceptional performance. Various methods are available for preparing graphene, and the electrochemical exfoliation method is chosen for its environmentally friendly, ease of operation, and strong controllability. However, the process of electrochemical exfoliation preparation is influenced by various factors, which still shows challenges of slow exfoliation speed and low yield. In this study, high-purity flexible graphite paper and a saturated calomel electrode (SCE) were used as a three-electrode system, using yield, interlayer spacing, and defect degree as evaluation criteria to explore the influence of electrolytic voltage and electrolyte concentration on graphite electrochemical exfoliation. Using dispersion state, settling time, and defect degree as evaluation criteria to examined the impact of dispersant type on the quality of graphene. The research demonstrated that electrochemical exfoliating at 10 V cell voltage with a bipolar distance of 2 cm in a 0.20 M Na 2 SO 4 solution at pH 7 and room temperature, followed by a 10 min ultrasound dispersion in a C 2 H 5 OH medium at a liquid–solid ratio of 1444:1. The efficiency of graphene production is 59.8%, with low defect levels ( I D / I G = 0.355), large interlayer spacing ( d = 0.350 nm), and a few layers (approximately 4 layers). In addition, the graphene dispersed in a N , N -Dimethylformamide (DMF) medium with a liquid–solid ratio of 1512:1 exhibits the highest level of stability.
研究领域:
材料科学
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电化学
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纳米技术
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
STUDIES IN CONSERVATION
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2019
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IF 0.797
Jing Zhao,Hongjie Luo,Xiao Huang
Currently, there is a lack of research on the migration and distribution of soluble salt solutions in the pores of fragile silicate cultural relics, especially the thermodynamic changes during crystallization, and the forces causing the destruction of cultural relics. Thus, this paper used infrared thermal imaging analysis and extended depth-of-field microscopy to observe the changes in temperature, morphology, migration, and crystallization rate of Na2SO4 solution – the most typical solution that causes damages to cultural relics – in the crystallization process and in different capillary pores. The results show that the formation of soluble salt crystal nuclei and subsequent crystal growth mainly occurred in the liquid phase region below the ambient temperature, and then the salt crystals in the deliquescent state became more compact due to the attractive force generated from liquid-phase water evaporation. Additionally, three stages of migration and crystallization of the salt solution in different capillary pores were found. Large-area crystals appeared in the capillary pore with a large diameter, and bubbles were generated. This is likely because the surface tension of the Na2SO4 solution decreased with increasing concentration, and the solubility of the air dissolved at the solid–liquid interface of the mouth of the capillary pore and the pressure in the capillary pore decreased. A self-designed double-layer contact surface internal pressure method and extended depth-of-field microscopy were used to carry out real-time online observation of the force applied on the contact surface during the crystallization of the salt solution. It was found that the airflow determined the direction of capillary movement of the solution, and water migration determined the laminar flow in the capillary pore. Salt crystallization played a role in distortion and shape-fixation of pores. Small spikes in the mass indicated that the expansion–contraction force generated by the salt solution during the crystallization process was in a state of constant change, and the degree of expansion was always slightly more significant than the change caused by contraction. Expansion forces dominated the surface of the sample. In this paper, the change in crystallization and the forces of the soluble salt solution were analyzed.
研究领域:
文物保护
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材料科学
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热力学
✓ 已验证
DOI
高影响因子
Journal of Chemistry
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2021
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IF 2.506
Xiaohui Song,Shuaiqi Sun,Lingzong Meng,Rongjian Ying,Yafei Guo,Tianlong Deng
The densities and pH values in the system NaBO2–Na2SO4–H2O at 298.15 K and 323.15 K were investigated. Combining the equilibrium constants for different boron species, the distributions of six boron species in the mixed solution were calculated with total boron concentration and pH values. The molar fractions of the six boron species are mainly affected by the total boron concentration and temperature, but rarely affected by the concentration of SO42–. The dominant boron species in the mixed solution at the two temperatures is B(OH)4‒. The mole fraction of B(OH)3, B5O6(OH)4‒, and B3O3(OH)4‒ can be neglected. The polyborate ions are easier to form as the temperature increases. The results of distribution for boron species in this study and those with the Pitzer model can both be used to describe the distribution of boron species in the mixed solution.
研究领域:
化学
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物理化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
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2022
·
IF 3.269
Shuaiqi Sun,Dan Li,Tao Zhang,Yong Ma,Lingzong Meng,Tianlong Deng,Yafei Guo
The solubilities and refractive indices in the systems NaCl–Na 2 SO 4 –H 3 BO 3 –H 2 O and NaCl–H 3 BO 3 –H 2 O at 323.15 K were investigated with the isothermal dissolution equilibrium method. The phase diagram of the ternary system consists of two single-salt crystallization fields of NaCl and H 3 BO 3 , two solubility univariant curves, and one invariant point. The dry-salt diagram of the quaternary system is composed of three single-salt crystallization fields corresponding to NaCl, Na 2 SO 4 and H 3 BO 3 , three solubility univariant curves, and one invariant point. A comparison of the diagrams of the quaternary system at (298.15, 323.15 and 373.15) K shows that areas of sodium chloride and sodium sulfate salts region increases whereas the area of H 3 BO 3 region decreases distinctly with temperature increasing. Combining the Pitzer parameters and solubilities in the ternary systems in this study and literatures, the lacking Pitzer parameters for H 3 BO 3 were fitted on the basis of Pitzer model. The calculated solubilities with the model agree well with the experimental data. The phase diagrams and Pitzer model for the quaternary system at 298.15 and 323.15 K were then used to conduct a computer simulation of brine separation. All H 3 BO 3 and most of Na 2 SO 4 can be separated from the solution with segmental evaporation method.
研究领域:
化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
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2016
·Vol. 92
·期 4
·827-833
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IF 2.738
Jinxi Feng,Shenyu Lan,Chunyang Yao,Ya Xiong,Shuanghong Tian
BACKGROUND Electro-generation of NaOH and H 2 SO 4 with organic compound-free Na 2 SO 4 wastewater has been known for many years, but actually, lots of Na 2 SO 4 wastewater contains organic pollutants, such as black liquor, dyeing and sulphonating wastewater etc., therefore, there is a strong demand for investigations on performance and effect of the organic pollutants in electrochemically splitting Na 2 SO 4 into H 2 SO 4 and NaOH from these wastewaters. RESULTS Co-electrolysis of Na 2 SO4 (1.13 mol L −1 ) and AO7 (50 ∼ 500 mg L −1 ) was investigated in a diaphragm cell with IrO 2 -coated Ti electrodes. It was found that the concentrations of the resulting NaOH and H 2 SO 4 could remain at about 0.73 mol L −1 and 0.36 mol L −1 , respectively, although the COD removal was increased from 50.3 mg L −1 to 166.3 mg L −1 with the increase of AO7 concentration, for 120 min. CONCLUSION In a diaphragm cell with IrO 2 -coated Ti electrodes, NaOH and H 2 SO 4 could be effectively generated, and simultaneously, AO7 could also be degraded for the wastewater containing Na 2 SO 4 and AO7. Interestingly, the electro-generation of NaOH and H 2 SO 4 was not significantly affected by the occurrence and degradation of AO7 in the range 0–500 mg L −1 . The phenomenon of constant acid–base yield contributed to the independence of the main acid-generating reactions on the electro-oxidation of AO7. © 2016 Society of Chemical Industry
研究领域:
环境科学
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电化学工程
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2017
·
IF 2.843
Yanqing Xu,Jiuyang Lin,Congjie Gao,Bart Van der Bruggen,Qiyang Shen,Hengzhi Shao,Jiangnan Shen
In this study, a high-flux organic solvent nanofiltration (OSN) membrane with the permeance of 66.7 Lm–2 h–1 bar–1 in methanol and 38.0 Lm–2 h–1 bar–1 in ethanol was successfully prepared from nanoporous PAN by phase inversion and hydrolyzation in sodium hydroxide solution. The polymer concentration and hydrolysis time were varied to control the final morphology and performance. The ternary phase diagram and viscosity measurements were used to describe precipitation thermodynamics and kinetics of the phase inversion process. The prepared membranes had a typical asymmetric structure, which could be observed from images of the cross section, comprising a dense skin layer and a porous substructure in the sublayer. It was found that the polymer concentration has an apparent influence on the morphology, selectivity and permeability of the prepared membranes. FTIR analysis, ζ-potential and water contact angle measurements confirm a molecular chain rearrangement as hydrogen bonds were formed between CONH2 and COOH groups during the carboxyl modification process. Moreover, an increase of the surface hydrophilicity was obtained by hydrolysis. A good solvent resistance and a satisfactory separation performance in the nanofiltration range were achieved with hydrolyzed PAN membranes in polar as well as nonpolar solvents. The relationship between solvent permeation and combined solvent properties (viscosity, molar diameter and solubility parameter) indicated a strong interaction of selected solvents with polymers except alkanes. The hydrolyzed PAN membrane was applied to fractionation of dyes and Na2SO4 solution compared to commercial NF membrane. The high dye rejection and salt permeance remained constant with the salt addition for high flux hydrolyzed PAN showing the fractionation potential for dyes and divalent salts, and establishing the strong advantage over commercial NF membranes.
研究领域:
材料科学
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环境工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Magnesium and Alloys
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2021
·
IF 10.088
Baojing Feng,Guonan Liu,Peixu Yang,Sensen Huang,Dongqing Qi,Peng Chen,Chengduo Wang,Jiang Du,Shaojun Zhang,Jinhui Liu
Effect of the second phase in the micro-galvanic corrosion of a commercial Mg alloy containing rare earth elements, cast WE43 alloy, was investigated in 0.6 M NaCl solution and 0.6 M Na 2 SO 4 solution by scanning electron microscopy (SEM) observations, scanning Kelvin probe force microscopy (SKPFM) analysis, hydrogen evolution, weight loss measurement, and electrochemical techniques. It is confirmed that the second phase of cast WE43 alloy is more active than Mg matrix and exhibits an anodic role in the micro-galvanic corrosion with α-Mg matrix as cathode and dissolves preferentially in Na 2 SO 4 solution, in contrast to the situation in NaCl solution. The corrosion rate of cast WE43 alloy in Na 2 SO 4 solution is much higher than that in NaCl solution, which is different from the conventional wisdom and could be attributed to the different role of the second phase in the micro-galvanic corrosion in two solutions.
研究领域:
材料科学
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腐蚀科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2019
·Vol. 91
·期 3
·431-440
·
IF 1.986
Zhang Cui,Shi Yan,Fu Zhifeng
We present an effective and environmental-friendly pathway to prepare SiO 2 hollow particles using Na 2 SO 4 particles as templates, which involved sol-gel silica coating on surface of the templates and subsequent removal of the Na 2 SO 4 templates by water-dissolution. Further, SiO 2 /TiO 2 double-shell hollow particles were prepared by coating TiO 2 on the surface of the hollow SiO 2 particles. The morphologies and structures of the synthesized hollow particles were characterized using SEM, TEM, XRD, FTIR, BET, and UV. The sizes and shapes of the hollow particles can be controlled by using Na 2 SO 4 templates with different sizes and shapes. The sizes of hollow particles were in the range from 500 nm to 15 μm. By changing the concentration of silicon precursor, the shell thickness of hollow SiO 2 particles can be controlled in the range of 25–200 nm. In addition, SiO 2 /TiO 2 double-shell hollow particles showed better photocatalytic degradation of Rhodamine B than that of hollow TiO 2 particles and solid TiO 2 particles.
In this study, we have successfully fabricated hollow SiO 2 particles with different shapes and size, as well as hollow SiO 2 /TiO 2 double-shell particles via a facile and environmentally friendly method employing water-soluble inorganic Na 2 SO 4 particles as template. The preparation process involved sol-gel silica and titania coating on surface of the template and followed by water-dissolution removal of the Na 2 SO 4 template.
研究领域:
材料科学
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纳米技术
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
WATER RESEARCH
·
2024
·
IF 11.4
Peng Feng,Donghai Xu,Youwei Zhi,Bing He,Shuzhong Wang,Yaling He,Yang Guo
This work aims to explore the ability of molten salt to solve salt deposition in supercritical water (SCW) related technologies including supercritical water oxidation and supercritical water gasification, with KNO 3 and Na 2 SO 4 as examples. In the pure KNO 3 solution, the two-phase layering of high-density KNO 3 molten salt (settling at the reactor bottom) and low-density saturated KNO 3 -SCW salt solution (flowing out at the top outlet of the reactor) was formed in a kettle-reactor with about 6.5 ratio of depth to inner diameter, thereby improving the accuracy of measured solubilities. The precipitation macro-characteristics of mixed KNO 3 and Na 2 SO 4 in SCW were investigated under different feed concentration conditions. The results showed that Na 2 SO 4 deposition on the reactor sidewall could be reduced by more than 90 % when the mass ratio of KNO 3 to Na 2 SO 4 in the feed was only 0.167. No visible salt deposition was observed on the sidewall when the ratio was 0.374. All solid deposited salts were converted into the liquid molten salt as the ratio reached 3.341, and thus could easily flow out of the reactor, without plugging. ‘Molten salt dissolution’ mechanism may provide a more plausible explanation for mixed KNO 3 and Na 2 SO 4 in SCW. In addition, the precipitation micro-mechanisms of mixed KNO 3 and Na 2 SO 4 , and the critical conditions of avoiding sidewall deposition and reactor plugging were proposed. This work is valuable for overcoming the salt deposition problem in SCW-related technologies.
研究领域:
化学工程
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环境科学
·
超临界流体技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
AMERICAN MINERALOGIST
·
2020
·Vol. 105
·期 11
·1686-1694
·
IF 2.924
Huan Chen,Hao Cui,Richen Zhong,Yuling Xie,Chang Yu,Zimeng Li,Yifan Ling
Sulfate is traditionally considered to have retrograde solubility in aqueous solutions. However, our recent hydrothermal diamond-anvil cell (HDAC) experiments have shown that the solubility of Na 2 SO 4 changes from retrograde to prograde in the presence of silica, leading to the formation of sulfate-rich solutions at high temperatures, in line with observations on natural geofluids. In this study, we use synthetic inclusions of fused silica capillary capsules containing saturated Na 2 SO 4 solutions and Na 2 SO 4 crystals to quantitatively investigate the solubility of Na 2 SO 4 at different temperatures in the Na 2 SO 4 -SiO 2 -H 2 O system. Sulfate concentrations were measured using Raman spectroscopy and calibrated using Cs 2 SO 4 solutions with known concentrations. The solubility of crystalline Na 2 SO 4 dropped slightly when heated from 50 to 225 °C and dramatically from 225 to 313 °C. At 313 °C, the Na 2 SO 4 crystals began to melt, forming immiscible sulfate melt coexisting with the aqueous solution, with or without solid Na 2 SO 4 . With the formation of sulfate melt, the solubility of Na 2 SO 4 was reversed to prograde (i.e., solubility increased considerably with increasing temperatures). The solubility of Na 2 SO 4 in the measured solution was significantly higher than that predicted in the absence of SiO 2 over the entire temperature range (except for temperatures around 313 °C). This indicates that the presence of SiO 2 greatly changes the dissolution behavior of Na 2 SO 4 , which may be caused by the formation of a sulfate–silicate intermediates such as Si ( OH ) 4 SO 4 2 − . Considering that most crustal fluids are silica-saturated, the solubility curve of Na 2 SO 4 obtained in this study can better reflect the characteristics of geofluids when compared to that of Na 2 SO 4 -H 2 O binary system. At temperatures of 313–425 °C, the solubility of Na 2 SO 4 increases with temperature following the function C sulfate = –3173.7/ T + 5.9301, where C sulfate and T represent the solubility of Na 2 SO 4 in mol/kg H 2 O and temperature in Kelvin, respectively. As an application, this temperature-solubility relationship can be used to evaluate the sulfate contents in fluid inclusions that contain sulfate daughter minerals, based on the temperature of sulfate disappearance obtained from microthermometric analysis. The sulfate concentrations of the ore-forming fluids of the giant Maoniuping carbonatite-related rare earth element (REE) deposit (southwest China) were calculated to be 4.67–4.81 m (mol/kg H 2 O). These sulfate concentrations were then used as internal standards to calibrate the previously reported semi-quantitative results of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) analysis of REE-forming stage fluid inclusions at this deposit. The calculated Ce concentrations in the REE-mineralizing fluid range from 0.42 to 0.49 wt%. The high fluid REE contents suggest that the sulfate-rich fluids are ideal solvents for REE transport. A mass-balance calculation was carried out to evaluate the minimal volume of carbonatite melt that was required for the formation of the giant Maoniuping REE deposit. The result indicates that the carbonatite dikes in the mining area are enough to provide the required fluids and metals, and thus a deep-seated magma chamber is not necessary for ore formation.
研究领域:
地球化学
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矿物学
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矿床地质
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热水系统
✓ 已验证
DOI
高影响因子
JOURNAL OF SUPERCRITICAL FLUIDS
·
2025
·
IF 4.4
Peng Feng,Donghai Xu,Gang Yin,Kunkun Song,Ruibo Wang,Zhiyuan Li,Pan Wang
This study investigated the corrosion behavior of 316 L (316LSS) and 304 (304SS) stainless steels under a Na 2 SO 4 deposition layer in supercritical water (SCW). The salt layer reduced oxide film densification versus pure SCW, with 304SS exhibiting more severe corrosion (e.g., pitting) due to the absence of Mo which resists pitting corrosion. Without the salt layer, oxide film thicknesses were 6.50 µm (316LSS) and 1.60 µm (304SS); in contrast, 6.52 µm and 9.33 µm, respectively, indicating thicker in SCW with the salt layer. At 723 K and 25 MPa, higher water density increased Ni/Fe ion solubilities, while the salt layer trapped these ions in the microenvironment between the layer and oxide film, generating a locally acidic and oxidizing environment via hydrolysis of Ni/Fe ions. This process accelerated metal ion leaching and oxide dissolution, further enhanced in the presence of SO 4 2- . Na 2 SO 4 deposition layer and SCW synergistically intensified corrosion in both alloys.
研究领域:
材料科学
·
腐蚀工程
✓ 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）