COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2024
·
IF 4.9
Kexin Li,Mingzhe Dong,Li Han,Mingzhen Li,Huifang Zhang,Xiushen Ye,Haining Liu,Siyuan Zhang,Quan Li,Honghui Liu,Guosheng Shi,Zhijian Wu
The electrolytic production of magnesium metal requires anhydrous MgCl 2 with a high-purity, which is usually prepared through the dehydration of MgCl 2 ·6H 2 O at a relatively high temperature. The Mg 2+ cations in MgCl 2 ·6H 2 O have a high affinity for water and the complete dehydration of MgCl 2 ·6H 2 O is difficult due to the hydrolysis of the hydrated Mg 2+ cations. The hydrolysis usually results in the formation of unwanted oxycompounds of magnesium. In this study, the effects of the addition of AlCl 3 and NH 4 Cl on the dehydration of MgCl 2 ·6H 2 O were investigated by comparing the thermal decomposition processes of MgCl 2 ·6H 2 O, MgCl 2 ·6H 2 O/AlCl 3 , and MgCl 2 ·6H 2 O/NH 4 Cl, using Raman, FT-IR, TG-DSC, XRD techniques and theoretical calculations. It was found that the addition of AlCl 3 or NH 4 Cl significantly reduces the dehydration energy barrier of MgCl 2 ⋅6H 2 O, decreases the dehydration temperature, and suppresses the hydrolysis of MgCl 2 ·6H 2 O. Anhydrous AlCl 3 can extract water from MgCl 2 ·6H 2 O at room temperature. The interactions between Al 3+ or NH 4 + and H 2 O, together with the substitution of Cl - for H 2 O, result in the easier production of anhydrous MgCl 2 . During the dehydration of MgCl 2 ·6H 2 O, several impurities including MgO are generated, indicating that the environment remains to be an important controlling factor for the dehydration of MgCl 2 ⋅6H 2 O. The results obtained would be helpful for understanding the dehydration processes and mechanisms of MgCl 2 ·6H 2 O under the assistance of AlCl 3 and NH 4 Cl, and for exploring new techniques for MgCl 2 ·6H 2 O dehydration.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
WATER RESEARCH
·
2021
·
IF 11.236
Jinxi Feng,Tiantian Zhang,Jingxiang Sun,Jinzhu Zhu,Wen Yan,Shuanghong Tian,Ya Xiong
Piezoelectric effect was firstly employed to improve dewatering efficiency of sludge. It was found that the piezoelectric effect could be driven directly by the pressure of pressure filtration process, without any additional energy. This piezo-dewatering process coupled piezoelectric effect with pressure filtration could efficiently remove moisture of sludge. Under 0.6 MPa for 2 h, moisture content (MC) and weight of sludge could be reduced to 63.9% and 3.2 g from 96.7% and 50 g by the piezo-dewatering process with 0.45 g t -BaTiO 3 . This piezo-dewatering efficiency was much higher than that of usual conditioning-pressure filtrations using CaO, FeCl 3 or polyacrylamide (PAM) as the conditioners. And the piezo-dewatering process assisted by PAM could further decrease MC and weight of the sludge to 54.9% and 2.1 g, correspondingly, which complied to the advanced dewatering requirement (MC < 60%). The favorable piezo-dewatering efficiency was contributed to the piezo-catalytic oxidation and the electric role of remnant piezo-field. The finding of this piezo-dewatering mechanism offered an inspiring look at developing the emerging dewatering technology.
研究领域:
环境工程
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废物管理
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2023
·
IF 5.2
Jingjing Zhou,Changqing He,Lin He,Xincheng Zhang,Ying Tian,Hong Sui,Xingang Li
Emerging nano-demulsifiers are efficient functional materials for separating emulsions. However, the size effects of nanoparticles on demulsification and the mechanisms of enhanced demulsification by nano-modification are still unclear. Herein, a nano-demulsifier (SiO 2 -mANP) was prepared by modifying carboxyl-modified aliphatic nonionic polyether (mANP) with nano-SiO 2 . Compared to single polyether, the SiO 2 -mANP significantly reduced the demulsification temperature from 60 °C to room temperature . The demulsification efficiency of the asphaltene-stabilized water-in-oil emulsion reached 91.0% within 10 min at room temperature (dehydration over 99.5% in less than 2 min at 60 °C). The size effects study showed that smaller SiO 2 -mANP nanoparticles (∼10 nm) performed better in demulsification due to their superior diffusion ability in continuous phase and greater adsorption at the oil-water interface. The electrostatic potential (ESP) and independent gradient model (IGM) were used for the first time to analyze the changes in non-covalent interactions between demulsifiers and water. Nano-modification facilitated the formation of more non-covalent interaction sites, notably hydrogen bonding sites such as silanol groups. This rearranged the molecular surface ESP of the demulsifier. As a result, the non-covalent interactions between demulsifier and water were greatly enhanced, leading to a significant reduction in the coalescence time of water droplets. This primary study on the size effects and non-covalent interactions of nano-demulsifiers will provide guidance for the design and development of highly efficient demulsifiers.
研究领域:
材料科学
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界面化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
·
2022
·Vol. 106
·期 9
·3625-3637
·
IF 5.56
Wang Juan,Qu Ge,Xie Leipeng,Gao Chao,Jiang Yingying,Zhang Yi-Heng P. Job,Sun Zhoutong,You Chun
Abstract Dihydroxy-acid dehydratase (DHAD) plays an important role in the utilization of glycerol or glucose for the production of value-added chemicals in the in vitro synthetic enzymatic biosystem. The low activity of DHAD in the dehydration of glycerate to pyruvate hampers its applications in biosystems. Protein engineering of a thermophilic DHAD from Sulfolobus solfataricus (SsDHAD) was performed to increase its dehydration activity. A triple mutant (I161M/Y145S/G205K) with a 10-fold higher activity on glycerate dehydration was obtained after three rounds of iterative saturation mutagenesis (ISM) based on computational analysis. The shrunken substrate-binding pocket and newly formed hydrogen bonds were the reason for the activity improvement of the mutant. For the in vitro synthetic enzymatic biosystems of converting glucose or glycerol to L-lactate, the biosystems with the mutant SsDHAD showed 3.32- and 2.34-fold higher reaction rates than the wild type, respectively. This study demonstrates the potential of protein engineering to improve the efficiency of in vitro synthetic enzymatic biosystems by enhancing the enzyme activity of rate-limited enzymes. Key points • A screening method was established for the protein engineering of SsDHAD. • A R3 mutant of SsDHAD with 10-fold higher activity was obtained. • The R3 mutant exhibits higher productivity in the in vitro biosystems. Graphical abstract
研究领域:
酶学
·
合成生物学
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生物催化
✓ 已验证
DOI
PubMed
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2025
·
IF 4.8
Ruxing Zhao,Qingrun Meng,Guanchao Wang,Lin Xu,Weifeng Chu,Junjie Li
Intermolecular dehydration of 2-propanol (IPA) to di-isopropyl ether (DIPE) serves as an important process to produce the valuable chemical, however, developing advanced solid acid catalysts with high DIPE selectivity faces the great challenge of inhibiting the intramolecular dehydration reaction. In this context, we developed a highly selective intermolecular dehydration MFI nanosheet catalyst by synergistically modifying its diffusion and acid properties. We found that the DIPE selectivity over nanosheet ZSM-5 catalysts were obviously higher than that over the conventional ZSM-5 catalyst, benefited from the enhanced diffusion property over nanosheet catalysts that inhibited the further conversion of DIPE. However, the DIPE selectivity were still lower than 70 % over those catalysts attributed to their high acid strength that facilitated the intramolecular dehydration reaction. Thus, various heteroatoms (Fe, Ga, and B) substituted MFI zeolite nanosheet catalysts were prepared and employed in the dehydration reaction, Fe-MFI with a moderate acid strength exhibited the highest DIPE selectivity among those catalysts. Besides, the effects of acid amounts (Si/Fe ratio) and diffusion properties (thickness of b-axis) on the intermolecular dehydration selectivity and activities over nanosheet Fe-MFI catalysts were systematically investigated. An optimal Fe-MFI nanosheet catalyst with the b-axis thickness of ∼20 nm and Si/Fe ratio of ∼40 presented the stable high DIPE selectivity of ∼91 % in 360 h of time on stream, meanwhile the IPA conversions kept almost unchanged.
研究领域:
催化
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材料科学
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化学反应工程
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纳米技术
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物理化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Dongdong Ge,Weixiang Wu,Guangming Li,Yuhui Wang,Guobiao Li,Yanting Dong,Haiping Yuan,Nanwen Zhu
Sludge dewaterability is commonly poor due to the hydrophilic biopolymeric substances. The highly efficient oxidation process is of great significance for extracellular biopolymers disintegration and bound water discharge. This work investigated the novel CaO 2 -enhanced peroxone (CaO 2 /O 3 ) process to adjust sludge characteristics for dewaterability enhancement and focused on the molecular composition and transformation of dissolved organic matters (DOM). CaO 2 /O 3 (60/40 mg/gTS (total solid)) treatment showed more powerful sludge solubilization of 57.8% and cell death proportion of 46.1% over single CaO 2 or O 3 treatment. Hydrophilic extracellular polymeric substances, especially protein-like substances, were substantially degraded, and their conformation turned to be more hydrophobic, and carbohydrate-like, aminosugars-like, and lignins-like substances increased in CaO 2 /O 3 process. Meanwhile, CaO 2 /O 3 handling resulted in more decomposition of CHO-containing compounds than N-containing or S-containing compounds. Subsequently, 60 mg/gTS PFS (polyferric sulfate) reflocculation exerted a strengthened role in eliminating proteins & lipids-like, lignins-like, and unsaturated hydrocarbons-like substances, and especially S-containing compounds, which compensated for the unsatisfactory removal effects of these substances in the CaO 2 /O 3 oxidation process. Therefore, the CaO 2 /O 3 -PFS treated sludge with less hydrated DOM easily harvested deep-dewatering in pressure filtration. Furthermore, it was noteworthy that the presence of CaO 2 created an alkaline environment and served as the source of sustained-release H 2 O 2 , which accelerated O 3 decomposition and greatly improved • OH generation. These findings provided molecular insight into a novel sludge conditioning approach for ideal dewaterability based on the CaO 2 -enhanced peroxone process in sludge treatment.
研究领域:
环境工程
·
污水处理
·
化学工程
✓ 已验证
DOI
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 36
·28233-28241
·
IF 3.84
Yuhe Xiu,Angjun Chen,Xuerui Liu,Chen Chen,Jizhong Chen,Li Guo,Ran Zhang,Zhenshan Hou
Novel polymer-supported Brønsted acid polymer catalysts have been successfully synthesized by radical polymerization, followed by a simple solvothermal route and ion exchange step. The as-synthesized co-polymers were characterized by Elemental Analysis, FT-IR spectroscopy, thermogravimetric analysis and scanning electron microscopy and then were employed as a heterogeneous catalyst for dehydration of sorbitol. Especially, the polymer catalysts have a unique advantage of adjustable Brønsted acidity, and the polymer with 1.82 mmol g−1 of Brønsted acidity was a very efficient catalyst for highly selective dehydration of sorbitol into 1,4-anhydro-D-sorbitol. The dehydration reaction can be completed within 4 h and the selectivity of 1,4-anhydro-D-sorbitol achieved 90%. Moreover, the present catalysts resisted acid-leaching and can be recycled in five consecutive cycles without obvious loss of activity.
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Shuting Zhang,Shuxin Li,Dongqin Yuan,Qiaoyun Gao,Yili Wang,Daxin Zhang
Pressurized electro-osmotic dewatering (PEOD) process is an emerging technology for high-efficiency solid-liquid separation of sludge and has garnered extensive interest. This study proposed a novel sequential conditioning process based on ozone (O 3 )/percarbonate (SPC) treatment followed by Fe 3+ coagulation, namely O 3 /SPC-Fe 3+ conditioning, to improve the performance of PEOD. The optimal operating conditions and the related dewatering performance of O 3 /SPC-Fe 3+ conditioning-PEOD process were investigated to verify the feasibility. The mechanisms of the O 3 /SPC-Fe 3+ conditioning on improving PEOD process were also discussed from the enhancement of the water/filtrate flow in pores. The results showed that 53.44 % water content and 0.95 g/g dry solid (DS) of bound water in dewatered sludge cake were attained in the O 3 /SPC-Fe 3+ conditioning-PEOD process with optimal O 3 aeration time of 12 min, SPC dosage of 0.0610 g/g DS and Fe 3+ dosage of 0.0310 g/g DS for sludge conditioning then 346 kPa mechanical pressure and 40 V voltage for dewatering. During the O 3 /SPC-Fe 3+ conditioning-PEOD process, the extracellular polymeric substance (EPS) matrix was disintegrated, and the inner EPS migrated to the outside along with water. The values of α-helix/(β-sheet + random coil) adjusted by O 3 /SPC-Fe 3+ conditioning process decreased to 7.38 and 5.12 in slime and LB-EPS, respectively, and these changes transformed to expose more hydrophobic sites. After conditioning, the proportion of protein-N decreased drastically from 81.67 % to 62.34 %, while the proportion of inorganic-N increased significantly from 18.33 % to 37.66 %, indicating that partial protein-N in EPS altered to inorganic-N. The enhancement of PEOD by the O 3 /SPC-Fe 3+ process can be attributed to the EPS hydrophobicity transformation and the degradation/mineralization of EPS by oxidation of generated ·OH. The former triggered the reduction of water/filtrate viscosity within the interfacial region of pores. The latter provoked the decrease of bulk viscosity of water/filtrate within the pores. These two effects relieved the viscous resistance to water/filtrate flow within pores and promoted dewatering.
研究领域:
环境工程
·
污水处理
✓ 已验证
产品关联
DOI
高影响因子
Catalysts
·
2019
·Vol. 10
·期 1
·43
·
IF 3.444
Xincheng Wang,Fenghe Zhao,Long Huang
Temperature programmed surface reaction (TPSR) was developed as a method for rapid screening of catalysts. In this study, a series of acid catalysts was screened for the low-temperature dehydration of glycerol to acrolein via TPSR. Results suggested that most catalysts show activity of glycerol conversion to acrolein at a greatly different temperature range. HY, SiO2supported H4SiW12O40(STA/SiO2), SO42−/ZrO2, and SO42−/TiO2were observed to be efficient for the conversion of glycerol into acrolein at 210 °C, which was significantly lower than that generally reported (250–340 °C). Moreover, high selectivity of acrolein was gained at 85% and 86% over SiW/SiO2and SO42−/TiO2, respectively. A new style catalyst, ZnCl2/SiO2, was also found to be highly selective to acrolein and evaluated in a conventional fixed-bed reactor. Especially, stability tests showed that the catalyst life was up to 300 h with no clear deactivation on ZnCl2/SiO2with hydrogen as dilution.Keywords:glycerol;low temperature dehydration;acrolein;TPSR
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Physical Chemistry Letters
·
2023
·
IF 5.7
Huiling Tang,Shuang Xu,Mingjie Li,Liqin Wu,Chenghao Duan,Huiming Luo,Biao Zhou,Mumin Rao,Yongcai Qiu,Guangxu Chen,Keyou Yan
Biomass ethanol is regarded as a renewable resource but it is not economically viable to transform it to high-value industrial chemicals at present. Herein, a simple, green, and low-cost CuCl2–ethanol complex is reported for ethanol dehydration to produce ethylene and acetal simultaneously with high selectivity under sunlight irradiation. Under N2 atmosphere, the generation rates of ethylene and acetal were 165 and 3672 μmol g–1 h–1, accounting for 100% in gas products and 97% in liquid products, respectively. An outstanding apparent quantum yield of 13.2% (365 nm) and the maximum conversion rate of 32% were achieved. The dehydration reactions start from the photoexcited CuCl2–ethanol complex, and then go through the energy transfer (EnT) and ligand to metal charge transfer (LMCT) mechanisms to produce ethylene and acetal, respectively. The formation energies of the CuCl2–ethanol complex and the key intermediate radicals (e.g., ·OH, CH3CH2·, and CH3CH2O·) were validated to clarify the mechanisms. Different from previous CuCl2-based oxidation and addition reactions, this work is anticipated to supply new insights into the dehydration reaction of ethanol to produce useful chemical feedstocks.
研究领域:
催化
·
绿色化学
·
有机转化
·
光化学
·
生物质转化
✓ 已验证
DOI
高影响因子
ENERGY
·
2015
·
IF 4.844
Zhihao Pan,C.Y. Zhao
Thermal energy storage systems improve the inefficiency of industrial processes and renewable energy systems (supply versus demand). Chemical reaction is a promising way to store thermal energy because of its high energy storage density , long-term energy storage, etc. This study investigated an MgO/H 2 O chemical thermal storage system that stores thermal energy by decomposing Mg(OH) 2 (endothermic reaction), and supplies thermal energy by combining water vapor with MgO (exothermic reaction). Heat supply is greatly influenced by MgO properties, particularly dehydration temperature. Therefore, the equilibrium hydration fractions of MgO prepared at various dehydration temperatures were measured. Then, the relation between dehydration temperature and the equilibrium hydration fractions of MgO was determined. The equilibrium hydration fractions of MgO at various hydration temperatures and pressures were also measured. The chemical thermal storage system was inefficient at dehydration temperatures lower than 350 °C or higher than 500 °C. The efficiency of this system can be improved by increasing the hydration temperature while keeping the relative vapor pressure unchanged.
研究领域:
能源科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Xiaomin Ma,Pengcheng Wen,Yuping Fan,Xianshu Dong,Maoqing Yang,Yuanpeng Fu
The objective of this study was to elucidate the synergistic dewatering mechanism of mixed sodium dodecylbenzene sulfonate (SDBS) and polyethyleneimine (PEI) on kaolinite filter cakes and to test the dewatering effectiveness of a custom-built pressure dewatering device. The dewatering experiments showed that while the reagent dose was reduced by 50%, the dewatering rate decreased to 19.78%, surpassing the optimal dose of a single reagent. During the natural compression stage of the filter cake, the deformation reached its maximum under the same pressure difference. During the transitional period, the closure of the filter cake pores occurred at a slower rate, facilitating better moisture drainage. Under strong compression, the ultimate deformation reached its maximum. PEI acted as a bridging agent for kaolin flocculation and served as a medium for SDBS on the kaolin surface. A small amount of PEI reduced the electrostatic repulsion of SDBS, increasing its adsorption capacity. PEI adsorbed on the kaolin surface through electrostatic and hydrogen bonding, while SDBS could adsorb onto the PEI reagent layer through electrostatic and polar interactions, exposing its alkyl chains on the surface and thereby facilitating flocculation and generating a hydrophobic reagent layer. This study could provide a new method and insights for the efficient pressurized dewatering of kaolin.
研究领域:
环境科学
·
矿物加工工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）