JOURNAL OF MOLECULAR LIQUIDS
·
2017
·
IF 3.648
Yong Zhou,Yinyan Gong,Yongli Huang,Zengsheng Ma,Xi Zhang,Chang Q. Sun
Solvation of acid, base, and salt is ubiquitously important to all subject areas in chemistry , health care and life science. However, fine resolution of the solvation dynamics, solute-solvent molecular interactions , and solute capability of transforming the hydrogen bond (O:H O, or HB) and surface stress remain great challenge. Incorporating the notion of O:H O bond cooperativity with a strategy of differential phonon spectroscopy (DPS) has enabled resolution on the fraction and stiffness of the solvent HB from the mode of water to the hydration shells upon NaOH, NaI and HI solvation. Results show that Na + and I + ionic polarization shortens the H O bond and stiffens its phonon from 3200 to 3500 cm − 1 in the hydration shells. The H + in the HI solution forms a H ↔ H anti-HB that disrupts the solution network and surface stress. The excessive electron lone pairs of OH – form the O : ⇔ : O super-HB that compresses the network, sharing the same effect of mechanical compression shifting the H O phonon from above 3100 cm − 1 to its below; the solute H O bond performs the same to the H O dangling bond at surface featured at 3610 cm − 1 . The fraction coefficients or phonon abundance transition, f H = 0, f HO ∝ C, and f x ∝ 1-exp(− C/C 0 ) (x = Na + and I − and C the solute concentration) towards saturation, feature the solute capability of HB transformation. Practice not only confirms the essentiality of the H ↔ H anti-HB point fragilization, the O : ⇔ : O super-HB point compression, and the ionic polarization to the performance of the respective HI, NaOH, and NaI solutions, but also demonstrate the power of the DPS that enables fine-resolution of solvation dynamics and solute capabilities.
研究领域:
化学
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医疗保健
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生命科学
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物理化学
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光谱学
✓ 已验证
DOI
高影响因子
CELLULOSE
·
2018
·Vol. 25
·期 10
·5659-5668
·
IF 3.809
Wang Guozhen,Meng Yan,Zhou Jinping,Zhang Lina
Abstract
Herein, one-step conversion of cellulose dissolved in 1.75 mol L −1 NaOH/0.074 mol L −1 ZnO aqueous solution to organic acids was realized through a hydrothermal degradation without heterogeneous catalyst. The effects of solvent, the concentrations of NaOH and ZnO, O 2 pressure, temperature and the reaction time on the yield of organic acids were investigated and discussed. The components of the degraded products were characterized with total organic carbon and high performance liquid chromatography. The results indicated that cellulose was depolymerized successfully to organic acids. Formic acid as the predominant species with 80.0% yield was obtained at the optimal conditions (150°C, 2 h, 3.0 MPa O 2 ), which was much higher than those reported in literatures. The small amount of ZnO in the solvent played an important role not only to promote the cellulose dissolution, but also to accelerate its oxidative degradation. The main features of this one-step degradation of cellulose were the green solvent, pre-dissolution of catalyst, and high selectivity. This work opened up a new avenue for the conversion of cellulose to organic acids under mild conditions. Graphical abstract The oxidative degradation of cellulose dissolved in NaOH/ZnO aqueous solution into organic acids was conducted under pressed O 2 without heterogeneous catalyst. The yield of FA which was the main product reached up to 80.0%.
研究领域:
生物化学
·
可再生能源
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2017
·Vol. 25
·期 4
·3922-3932
·
IF 2.741
Yi Xiaofeng,Yang Meixia,Mo Liuda,Xu Wenkai,Wang Shuai,He Jiarui,Gu Junjie,Ou Minrui,Xu Xiaoping
Copper in drinking water causes a significant environmental problem. Composite material based on alginate hydrogel has been gaining attention in the field of Cu(II) adsorption. However, alginate-based hydrogel exhibits poor mechanical property and relative low adsorption capacity which limit their application. The present study is devoted to the modification of chitosan/calcium alginate/Fe 3 O 4 (CAF) hydrogel microsphere by NaOH solution for enhancement of Cu(II) adsorption. Results reveal that modification of CAF via NaOH solution significantly improves the mechanical strength and Cu 2+ adsorption capacity of pristine materials. FTIR and XRD analysis confirms that CAF and newly prepared materials (NACAF) are successfully prepared. SEM and EDX are employed to analyze the surface morphology and elemental composition, respectively, both before and after their loading with Cu 2+ . XPS study demonstrates adsorption mechanism is based on chelation and ion-exchange. Compressive stress-strain curves demonstrate NACAF has better mechanical performance than CAF. The adsorption kinetics of the two adsorbents follow a pseudo-second-order model. The equilibrium data were best described by Langmuir isotherm model, and the estimated maximum equilibrium sorption capacity, q
m ,is 261.31 mg/g for the NACAF, which is larger than that of CAF (145.39 mg/g). Hence, NACAF shows excellent mechanical strength and high sorption capacity for Cu 2+ . It has great potential for Cu(II) removal in aqueous solutions.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2020
·
IF 3.232
Angxin Tong,Xiaojun Tang,Feng Zhang,Bin Wang
In this study, we mainly focused on predictable regularities of the red shift of ultraviolet spectra for β-phenylethylamine (PEA), NaCl and NaOH in aqueous solution. The absorption peaks of the UV spectra near 191 nm of NaCl, NaOH and PEA in aqueous solution moved in the direction of a red shift while the molar absorption coefficient at the peak increased regularly with the increasing solution concentration. These shifts were obtained for solutions with concentrations ranging from 3.68 to 1000 mmol/L for NaCl, from 0.762 to 2000 mmol/L for NaOH, and from 0.0515 to 8.91 mmol/L for PEA. The plots of the logarithm of the solution concentration for NaCl and PEA versus the absorbance at 191 nm and at the peak were linear, and the plots of the logarithm of the solution concentration for NaCl and PEA versus the wavelength at the peak (shifted from 191 nm) were also linear. In addition, the plots of the logarithm of the solution concentration for NaOH that ranged from 0.762 to 1.96 mmol/L versus the absorbance at 191 nm and at the peak were linear as well as the plots of the logarithm of the solution concentration for NaOH that ranged from 1.96 to 2000 mmol/L versus the wavelength at the peak. The slopes of the absorbance at 191 nm of PEA, NaCl and NaOH were somewhat similar to the absorbance at the peak separately, whereas the slopes of the wavelengths at the peak were different from them. Finally, in order to obtain the predictable regularity of the red shift of the UV spectrum for the mixture, 22 ternary mixtures were prepared. The results indicate that the inhibiting effect of hydroxide ions (OH-) caused the wavelength near 206 nm to remain unchanged when the solution concentration of NaOH in the mixture was more than 0.762 mmol/L.
研究领域:
化学
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光谱学
·
分析化学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry C
·
2020
·Vol. 8
·期 30
·10333-10341
·
IF 7.059
Jiaqi Sheng,Xiaofang Liu,Chengzhi Niu,Yufeng Sun,Yao Chen,Hengyang Wang,Bin Zhang,Guoyu Wang,Xiaoyuan Zhou,Guang Han
Bottom-up solution synthesis has been considered as a facile and energy-efficient approach for SnSe thermoelectric materials. Herein, we report a microwave-assisted hydrothermal method for the fast and controllable synthesis of SnSe with optimised thermoelectric properties. The NaOH concentration in solution precursors was demonstrated as a key factor influencing the phase composition, diameter, and morphology of the hydrothermal products as well as the thermoelectric properties of the corresponding sintered pellets. It is found that a NaOH : SnCl2 molar ratio of 30 leads to the formation of phase-pure SnSe microrods, and the pellet constructed from these rods obtains a maximum ZT of 1.08 and 0.78 at 773 K in parallel and perpendicular alignments to the pressing direction, respectively. These ZT values are significantly higher than the ZT value achieved by the pellet that was sintered from the hydrothermal powders prepared without NaOH and comprised the mixed phases of SnSe, SnO2, and SnSe2. This enhancement is primarily due to the improved power factor together with the lower lattice thermal conductivity owing to the significantly reduced fraction of SnO2 in the pellet. This study not only provides a microwave-assisted solution strategy for the fast, efficient, and controllable synthesis of SnSe materials, but also identifies the key synthesis parameters for securing better thermoelectric performance.
研究领域:
材料科学
·
能源材料
·
热电材料
✓ 已验证
DOI
高影响因子
IONICS
·
2018
·Vol. 25
·期 5
·2211-2219
·
IF 2.347
Chen Si,Gao Lin,Zhang Lulu,Yang Xuelin
Four types of mesoporous Na 2 Ti 3 O 7 (NTO) microspheres have been successfully prepared utilizing different concentrations of NaOH treatment. The specific surface areas and pore size distributions of NTO can be well controlled by means of adjusting the amount of NaOH additives. In the meanwhile, the corresponding electrochemical performance has been detected and analyzed. It is concluded that the 3 M-NTO sample prepared with 3 M NaOH solution exhibits the best electrochemical performance. We consider that the less or excess amount of NaOH might not be beneficial to building the most optimal model for efficient Na + ion storage. The addition of NaOH less than 2 M leads to the relatively low surface areas and pore volume, bringing about limited contact areas between active materials and Na + ions as well as unsatisfied specific capacity. On the other hand, the excess augment of NaOH is reversely detrimental to the improvement of electrochemical performance probably owing to the fragile construction of NTO caused by the abundant mesopore distribution.
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2021
·Vol. 11
·期 60
·37760-37766
·
IF 3.361
Xiaodong Yang,Jia Li,Jianhua Yao,Tianrui Ren,Bo Zhang
The precise control architectures of Cu2O crystals are very crucial, which have a significant influence on their various performances. Herein, Cu2O crystals with diverse architectures were achieved via finely adjusting the concentration of NaOH. The intriguing results showed that the addition of specific amounts of OH− to the solution was crucial to tailor the morphology and size of the resulting microcrystals. We observed the evolution of the shapes of the Cu2O microcrystals, which change from a rhombic dodecahedron to spherical, octahedral-like and then to hexapod upon the increase in the NaOH concentration. Adjusting the volume of NaOH added provides a means to vary the particle size. Furthermore, density functional theory (DFT) may reveal that OH− ions serve as an efficient coordination agent selectively adsorbing onto different crystal faces of Cu2O crystals modifying the crystal energies, inducing the structure anisotropy on crystal growth. This work reveals that an effective and facile strategy has been developed for morphology-control of Cu2O crystals.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2019
·
IF 6.393
Mingyu Chen,Sheng Xue,Liu Liu,Zongbao Li,Haiyan Wang,Chunlin Tan,Jianxin Yang,Xiaowen Hu,Xiao-Fang Jiang,Yupeng Cheng,Hongcheng Wang,Xiaobo Xing,Sailing He
We report a highly stable humidity sensor based on nanocomposite film obtained by depositing Au nanoparticles on the surface of 3-mercaptopropionic acid (MPA) capped CdTe quantum dots (QDs) and then modifying NaOH (CdTe@Au/NaOH). The CdTe@Au/NaOH film will form compound salts that can be dissolved or crystallized with humidity changes, resulting in a significant absorption variation of green light, which is very benefit for water vapor detection. In this study, we systematically investigated the influence on the performance of humidity sensing by varying the thickness of Au layer as well as the concentration of NaOH. Our results show that the quickest response-recovery time (˜less than 30 s) was found in the sensing film with the Au layer thickness of 20 nm and NaOH concentration of 1M, which can be ascribed to the combined effects of the better morphology and the yield of compound salts. The repeatable response and recovery measurements demonstrate that the designed sensors exhibit an ultralow humidity detection level with fast response-recovery time, high stability and reproducibility at room temperature. The simplicity, low fabrication cost, and wide working range of the humidity sensor will pave the way for its application in environments and gas detection.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
·
2023
·
IF 7.8
Yue Zong,Song Su,Ruijun Zhang,Yan Sun,Jiayu Tian,Bart Van der Bruggen
How to simultaneously improve the water permeance and antibiotics/minerals selectivity is one of the key issues for promoting the efficiency of drinking water treatment with nanofiltration (NF) technology . In this study, the post-treatment with a ternary complex of ethanol-water-NaOH (denoted as EWN) was used on four commercial NF membranes (NF270, NF90, HS-200C, and DF100) to understand its modification mechanism and promote the tetracycline removal efficiency. It was confirmed that the polyamide layers of all four commercial NF membranes were thinner after EWN post-treatment along with a slight increase in the pore size and enhancement in hydrophilicity and electronegativity . As a result, the water permeation of NF270 was improved by 70% and that of the other three membranes was increased by 19–20% while keeping a high tetracycline rejection of over 99%. Simultaneously, mineral ions such as K + , Ca 2+ , Mg 2+ , and Cl - passed the post-treated commercial NF membranes more easily. This yields a facile strategy for the performance regulation of existing, or commercial NF membranes.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2018
·
IF 3.193
Zhenzhen Jin,Kai Qi,Yubing Qiu,Zhenyu Chen,Xingpeng Guo
Free-standing polypyrrole (PPy) films hold promising potential in flexible energy storage devices, actuators, and artificial muscles, but they are limited by service failure. In this work, free-standing PPy/p-toluenesulfonate (PPy/pTS) films with different thickness (1.8 and 4.2 μm) were prepared, and their degradation behavior in aerated and de-aerated 0.5 M NaOH was investigated to make clear the changes of chemical and electrochemical degradation processes on free-standing PPy films. The degradation of electrochemical activity of the free-standing PPy film leads to an obvious increase in its internal resistance and shows similar kinetics as the PPy film with a Pt substrate, i.e. one degradation stage and its rate follows first-order kinetics. The degradation rate constant ( k ) in aerated NaOH increases largely owing to the existence of the dominant electrochemical degradation process. The k value of the thick film (4.2 μm) decreases obviously resulting from a more ordered and compact structure, which limits ion diffusion in the polymer matrix so as to greatly inhibit the chemical degradation process. The free-standing PPy film shows lower electrochemical activity and much larger k values compared with the PPy film with a Pt substrate under the same condition. The mechanisms involved were discussed.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Yafei Guo,Chang Tan,Jian Sun,Weiling Li,Jubing Zhang,Chuanwen Zhao
Business cost concern of solid CO 2 adsorbents has motivated the production of porous activated carbons from waste biomass materials. In this work, porous activated carbons were prepared from sugarcane bagasse using different activating agents (air, CO 2 , H 3 PO 4 and NaOH). Chemically activated porous carbons exhibited better physicochemical properties as compared to the physically activated carbons. Particularly, NaOH-activated carbon (CAC-S) featured a high specific surface area (1149 m 2 /g) and a large pore volume (1.73 cm 3 /g). X-ray photoelectron spectroscopy (XPS) analysis confirmed that the CAC-S adsorbent exhibited enhanced total basicity. The desired CAC-S adsorbent showed superior isothermal CO 2 uptakes of 5.50 and 4.28 mmol CO 2 /g at 0 °C and 25 °C and 1 bar. The isosteric heat of adsorption was predicted as 43.96 kJ/mol from the Clausius-Clapeyron equation and Toth model, which indicated intensified interaction between CO 2 molecules and the basic carbon surface. The excellent CO 2 adsorption performance should be associated with the improved textural properties and enriched surface basicity benefited from NaOH activation. Overall, CAC-S is considered as a promising adsorbent for CO 2 adsorption. The recycling of sugarcane bagasse as solid CO 2 adsorbents presents environmental implications with respect to waste management and pollutants mitigation.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
WATER RESEARCH
·
2019
·
IF 7.913
Shuhui Sun,Shu Wang,Yuxuan Ye,Bingcai Pan
Considerable amount of phosphorous is present as organic phosphonates (usually in the form of metal complexes, e.g., Ca(II)-phosphonate) in domestic and industrial effluents , which cannot be effectively removed by traditional processes for phosphate. Herein, we employed a proprietary process, i.e., Fe(III) displacement/UV irradiation/co-precipitation (denoted Fe(III)/UV/NaOH), to enable an efficient removal of Ca(II)-phosphonate complexes from water. The combined process includes three basic steps, i.e., Fe(III) replacement with the complexed Ca(II) to form Fe(III)-phosphonate of high photo-reactivity, UV-mediated degradation of Fe(III)-phosphonate to form phosphate and other intermediates, and the final phosphorous removal via co-precipitation at pH = 6. The operational conditions for the combined process to remove a typical phosphonate Ca(II)-NTMP (nitrilotrismethylenephosphonate) are optimized, where ∼60% NTMP is transformed to phosphate with the total phosphorous reduction from 1.81 mg/L to 0.17 mg/L. Under UV irradiation, the cleavage of NTMP is identified at the C-N and C-P bonds to form the intermediate products and phosphate in sequence. Also, the combined process is employed for treatment of two authentic effluents before and after activated sludge treatment, resulting in the phosphorous drop from 4.3 mg/L to 0.23 mg/L and from 0.90 mg/L to 0.14 mg/L respectively, which is much superior to other processes including Fenton/co-precipitation. In general, the combined process exhibits great potential for efficient removal of phosphonates from contaminated waters .
研究领域:
环境科学
·
水处理技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）