BMC Chemistry
·
2022
·Vol. 16
·期 1
·1-10
·
IF 4.095
Xiang Qing,Qin Jiyao,Qin Taihong,Chen Lu,Zhang Daixiong
Electrophoretic deposition (EPD) coating has become a hot topic due to its simple experiment, wide application, and wide material range. In this study, the PTFE coating was successfully prepared by electrophoretic deposition through the systematic study of electrophoretic deposition kinetics. In particular, in the dispersion system with ethanol as solvent, Nafion and NaOH were simultaneously added as additives to obtain a beneficial synergistic effect on PTFE electrophoretic deposition. And the best additive scheme is: when the concentration of PTFE was 6 g·L− 1 and the deposition time was increased to 20 min, adding 0.10 g·L− 1 Nafion and 0.10 mM NaOH simultaneously. Compared with the scheme with Nafion being only additive, the addition of NaOH can improve the deposition rate from 0.16 mg·cm− 2 to 0.98 mg·cm− 2, and the deposition rate increases by about 6 times. According to electrophoretic deposition kinetics, there is an obvious critical transition time between linear and parabolic regions in the preparation of the coating. Prolonging the arrival of critical transition time is beneficial to effectively achieve stable growth of the coating in a longer time. It is found that a more ideal additive can not only increase the deposition rate of coating, but also significantly accelerate the arrival of critical transition time. Meanwhile, the deposition voltage also has an important influence on the critical transition time. Increasing the voltage can improve the deposition speed but shorten the critical transition time. Therefore, the application of deposition voltage needs to strike a balance between deposition rate and critical time point. The optimal deposition conditions proposed in this work are: deposition voltage 60 V, deposition time 20 min, additive 0.10 g·L− 1 Nafion and 0.10 mM NaOH.
研究领域:
材料科学
·
表面工程
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高影响因子
ENVIRONMENTAL RESEARCH
·
2022
·
IF 8.431
Shijin Dai,Libing Liu,Hongping He,Bo Yang,Deli Wu,Youcai Zhao,Dongjie Niu
Molten salt has been increasingly acknowledged to be useful in the destruction of chlorine-containing organic wastes (COWs), e.g., organochlorine . However, the operational temperatures are usually high, and local structure and thermodynamic property of the molten salt remain largely unclear. In this study, novel molten NaOH-KOH is developed for organochlorine destruction, and its eutectic point can be lowered to 453 K with 1:1 mol ratio of NaOH to KOH. Further experiment shows that this molten NaOH-KOH is highly-efficient towards the destructions of both trichlorobenzene and dichlorophenol, acquiring the final dechlorination efficiencies as 88.2% and 94.1%, respectively. The organochlorine destruction and chloride salt enrichment are verified by fourier-transform infrared spectrometer . Molten NaOH-KOH not only eliminates the C-Cl and C C bonds, but also traps generated CO 2 , other acidic gases, and possibly particulate matters as a result of the high surface area and high viscosity. This makes it possibly advantageous over incineration for organic waste destruction for carbon neutrality . To sufficiently reveal the inherent mechanism for the temperature dependent performance, molecular dynamics simulation is further adopted. Results show that the radial distance between ions increases with temperature, causing larger molar volume and lower resistance to shear deformation. Moreover, thermal expansion coefficient, specific heat capacity, and ion self-diffusion coefficient of the molten NaOH-KOH are found to increase linearly with temperature. All these microscopic alterations contribute to the organochlorine destruction. This study benefits to develop highly-efficient molten system for COWs treatment via a low-carbon approach.
研究领域:
环境科学
·
化学工程
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BIORESOURCE TECHNOLOGY
·
2013
·
IF 4.75
Long Lin,Shang-Ru Zhai,Zuo-Yi Xiao,Yu Song,Qing-Da An,Xiao-Wei Song
In continuation of previous work on utilizing rice husks, this study aimed to prepare mesoporous activated carbons using residues of sodium hydroxide-pretreated RHs, and then examine their dye adsorption performance. The influences of the activation temperature and activation time on the surface area, pore volume, and pore radius of the activated carbon were investigated based on nitrogen adsorption/desorption isotherms and transmission electron microscopy. The adsorptive behavior of the mesoporous activated carbons obtained under optimum preparation conditions was evaluated using methyleneblue as the model adsorbate. The adsorption kinetics was studied by pseudo-first-and pseudo-second-order models, and the adsorption isotherms were studied by Langmuir and Freundlich models. The pseudo-second-order model and Langmuir isotherm were found to fit well the adsorption characteristics of the as-prepared mesoporous activated carbons. Thermodynamic data of the adsorption process were also obtained to elucidate the adsorption thermo-chemistry between the activated carbons produced from NaOH-pretreated RHs and MB molecules.
研究领域:
环境科学
·
材料科学
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Catalysts
·
2023
·Vol. 13
·期 6
·918
·
IF 3.9
Siqi Lv,Xiaolong Ma,Qingling Fu,Yanhui Zheng,Zichuan Ma
The utilisation of activated porous carbon (APC) for the removal of volatile methyl siloxane (VMS) has attracted significant research attention. However, the development of materials with high adsorption capacity remains a challenge. In this study, we successfully developed a high-specific-surface-area (2551 m2g−1) APC material with a large porous texture (1.30 cm3g−1) using coconut shell waste and NaOH as the activating agent. The performance of the APC material in the removal of hexamethyldisiloxane (L2) was evaluated using a fixed-bed dynamic adsorption setup. Notably, at 0 °C, the APC demonstrated a remarkable L2 removal ability, achieving a breakthrough adsorption capacity of 898.6 mg g−1. By increasing the inlet concentration of L2 and decreasing the temperature appropriately, the L2 adsorption capacity could be further improved. One advantage of APCs is their simple recycling process, which allows for sustained adsorption performance even after five consecutive cycles of adsorption and desorption. Therefore, the prepared APC material holds great promise as an efficient adsorbent for the removal of VMS.
研究领域:
材料科学
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环境工程
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Yanqing Zheng,Xiheng Kang,Zi You,Yihan Li,Yongheng Huang,Tieguang He,Tianming Su,Arthur J. Ragauskas,Zhenglong Li,Qiong Wang,Xueping Song
As an “upstream” process in biorefinery, biomass dismantling can dismantle the natural stable structure of lignocellulosic biomass and separate its three major components. To increase the value of the entire biomass by fully utilizing the three main components (cellulose, lignin, and hemicellulose), this study proposes a two-step decomposition system combining formic acid (FA) pretreatment and ethylene glycol-NaOH (EGA) dismantling, aiming to effectively convert sugarcane bagasse into xylose, fermentable glucose, and high-value lignin. In the first step, FA pretreatment removed 79.85 % of hemicellulose at 140 °C for 90 min with 3 % FA. Based on the first step, further combination of EGA dismantling can achieve a hemicellulose removal rate of 92.05 % and a lignin removal rate of 95.90 %. In addition, the solid residue was hydrolyzed by enzymes, and the glucose conversion rate was close to 83.29 % when the cellulase dosage was 10 FPU/g. In addition, the lignin recovered by this system retained 83.62 % of the natural β-O-4 structure, which has the potential to catalyze the formation of aromatic monomers. In summary, this gentle two-step system simultaneously improves the efficiency of lignocellulose decomposition and produces different value-added products, demonstrating the potential for industrial-scale production.
研究领域:
生物化学
·
生物质能工程
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APPLIED CATALYSIS A-GENERAL
·
2025
·
IF 4.8
Zheng Cui,Yueli Wen,Bin Wang,Maohong Fan,Faraz Ahmad,Hui Bai,Wei Huang
Activation of hydrogen atoms of methyl in toluene and methanol is crucial for side-chain alkylation of toluene with methanol. Herein, two strategies were applied, introducing dehydrogenation component (Cu) and tailoring the catalyst acid-base property with NaOH. A series of Cu and NaOH dual-modified PAl-NaX catalysts were prepared by in-situ hydrothermal method, the synergistic effect of Cu and NaOH was investigated. It is revealed that the product of (medium base)* (weak acid) and surface Cu δ+ percentage is crucial in controlling the total yield of side chain alkylation products by enhancing ethyl benzene selectivity. Cat-3Cu-13Na exhibits the optimal catalytic performance with an average methanol conversion of 97.25 % and an average total yield of side chain alkylation products of 77.46 % without obvious deactivation occurs in 192 h, and Cat-3Cu-19Na shows a promising styrene selectivity of 44.06 %. The decrease of weak acid sites might result in the decline in selectivity of styrene.
研究领域:
化学工程
·
催化反应
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PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
·
2026
·
IF 7.9
Hongping He,Yong Cheng,Linhua Jiang,Youcai Zhao,Dongjie Niu,Xunchang Fei,Rong Zhang,Shijin Dai
Thermo-chemical conversion (TCC) is an effective strategy in the detoxification of waste salt (WS) containing hazardous organics, which can be enhanced by molten salt, e.g., molten NaOH-KOH. However, the microscopic process remains largely unclear. With the WS collecting from a pesticide enterprise, this study comprehensively investigated the pyrolysis and combustion behaviors based on TG and FTIR. Particularly, molten NaOH-KOH mediation was explored. The results showed that combustion appeared to be more advantageous than pyrolysis for WS detoxification. Moreover, attributing to the enhanced heat transfer and catalytic activity of molten NaOH-KOH, the detoxification was promoted, manifested as a decrease in the peaked temperature of organic reactions (from 192 ℃ to 147 ℃). In addition, the emissions of C x H y , CO, and SO 2 decreased by 55.4 %, 88.2 %, and 74.1 %, respectively, due to the trapping effect by molten NaOH-KOH. Afterwards, continuous operation was conducted, and the results showed that the total organic carbon of the treated WS reduced evidently by 75.9 %, indicating stable and satisfactory performance. This study is of significance for understanding the WS transformation during TCC, especially when the molten salt is involved. The effective suppression of gas emissions under controlled conditions and the stable performance during continuous operation demonstrate the potential of this process for large-scale applications in the future.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2026
·
IF 8.3
Qiang Gao,Yang Hu,Hongyun Hu,Chan Zou,Xinhong Yuan,Xian Li,Hong Yao
Hydrogen production from organic solid waste via pyrolysis is a low-carbon and promising way. However, low hydrogen conversion capability limited by heat transfer and catalysis hinders highly efficient utilization of solid waste pyrolysis gases. In this study, the selected NaOH–Na 2 CO 3 binary salt was introduced to optimize H 2 production during thermal treatment of waste tires, and the characteristics of hydrogen distribution and its generation mechanism were investigated. The results demonstrated that molten salt treatment increased H 2 yield by 17 times compared to conventional pyrolysis at 575 °C, and H 2 share in pyrolysis gas exceeded 72 vol%. An increase in temperature also increased hydrogen yield under molten salt conditions, and the hydrogen yield rose to 14.3 mmol/g-feedstock at 575 °C. Additionally, molten salt exhibited large H 2 production with over 2 mmol/g-feedstock for large particle feedstocks with a particle size of 10 mm. According to oil analysis and rubber pure substance validation, molten salt promoted the Diels-Alder reaction and aromatization of butadiene monomers from the decomposition of cis -butadiene and styrene-butadiene rubber, leading to the release of hydrogen and increasing the H 2 concentration level in the pyrolysis gas. This study provides a technical practice for the hydrogen production from solid waste.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2026
·
IF 9.6
Pengli Bai,Huimin Fang,Weiguo Wang,Enzhou Liu
Treating H 2 S in a NaOH/Na 2 SO 3 solution simultaneously transforms it into H 2 /Na 2 S 2 O 3 . • Precise control of the Se/S atomic ratio in CdS 1− x Se x solid solutions enables continuous bandgap tuning. • The construction of a NiS 2 /CdS 0.90 Se 0.10 Schottky heterojunction enhances interfacial charge separation efficiency. • Investigation of the compositional evolution of CdS 0.90 Se 0.10 under varying alkaline conditions and its intrinsic mechanism underlying enhanced hydrogen evolution activity. Photocatalytic conversion of toxic hydrogen sulfide (H 2 S) waste gas into high-purity hydrogen (H 2 ) and value-added sulfur-containing chemicals has emerged as a transformative technological solution for enhancing sustainability in the coal chemical and petrochemical sectors. In this study, a selenium (Se) doping strategy was employed to synthesize CdS 1- x Se x solid solution photocatalysts, enabling precise band-gap modulation to alleviate rapid charge recombination and photo-corrosion of CdS. At an optimized Se content of x = 0.10, the resulting material exhibits a more negative conduction band minimum, thereby enhancing the thermodynamic driving force for H 2 evolution. Subsequently, a Schottky junction was constructed by depositing NiS 2 cocatalyst onto the surface of CdS 0.90 Se 0.10 (CSS). The 2 wt % NiS 2 /CSS composite delivered a H 2 evolution rate of 3.5 mmol g −1 h −1 in an H 2 S-saturated solution (0.2 M NaOH, 0.6 M Na 2 SO 3 ), corresponding to a 2.9-fold enhancement over pristine CSS. Electrochemical characterization showed that incorporation of the NiS 2 cocatalyst reduced the charge-transfer resistance and H 2 evolution overpotential, and increased the electrochemically active surface area. Fourier transform infrared spectroscopy, ultraviolet–visible diffuse reflectance spectroscopy, and thiosulfate (S 2 O 3 2− ) titration confirmed the concurrent conversion of H 2 S to S 2 O 3 2− . Moreover, the alkaline reaction medium contributed to improved catalyst stability. This synergistic strategy addresses the twin challenges of chalcogenide photocorrosion and decomposition of waste H 2 S, thereby providing experimental evidence for the valorization of sulfur-containing wastes and H 2 production. This study reports a CdS 1- x Se x /NiS 2 photocatalytic system that achieves efficient, alkaline-mediated conversion of toxic H 2 S into high-purity H 2 and S 2 O 3 2− , while simultaneously suppressing photocorrosion and enhancing charge separation. It establishes a robust, sulfur-centered strategy for H 2 S valorization. Download: Download high-res image (310KB) Download: Download full-size image
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Polymers
·
2020
·Vol. 12
·期 8
·1735
·
IF 3.426
Ke Li,Huiyu Yang,Lang Jiang,Xin Liu,Peng Lang,Bo Deng,Na Li,Weilin Xu
Dissolving cellulose in water-based green solvent systems is highly desired for further industrial applications. The green solvent glycerin—which contains hydrogen-bonding acceptors—was used together with NaOH and water to dissolve cellulose. This mixed aqueous solution of NaOH and glycerin was employed as the new green solvent system for three celluloses with different degree of polymerization. FTIR (Fourier-transform infrared), XRD (X-ray diffractometer) and TGA (thermogravimetric analysis) were used to characterize the difference between cellulose before and after regenerated by HCl. A UbbeloHde viscometer was used to measure the molecule weight of three different kinds of cellulose with the polymerization degree of 550, 600 and 1120. This solvent system is useful to dissolve cellulose with averaged molecule weight up to 2.08 × 105g/mol.Keywords:cellulose;glycerin;dissolution;green solvent;aqueous solution
研究领域:
材料科学
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化学工程
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Environmental Chemistry Letters
·
2020
·Vol. 18
·期 4
·1441-1446
·
IF 5.922
Zhao Xudong,Chen Zhiguo,Che Mingda,Qiu Sha,Huang Renliang,Qi Wei,He Zhimin,Su Rongxin
Pollution of waters by chlorinated organic pollutants is difficult to clean using actual remediation methods because these pollutants are highly stable. For instance, chloroform (CHCl 3 ) is poorly reactive with common oxidants such as iron-activated persulfate, ozone and Fenton’s reagents. Therefore, there is a need to develop new oxidants. Here, we designed a new dechlorination system, in which tannic acid and NaOH work synergistically to activate persulfate. We tested the effect of temperature and concentrations of persulfate, NaOH and tannic acid, on chloroform removal from water. Free radical-quenching experiments were performed to identify active species. Results show that chloroform removal increased from 42.5 to 97.6 wt.% after the addition of 300 mg/L tannic acid in 0.4 M NaOH. Superoxide radicals (O
·− 2
) was primarily responsible for the degradation of chloroform in the persulfate/NaOH/tannic acid system, in which tannic acid reacts with persulfate to produce hydroperoxide. Hydroperoxide then reduces persulfate to generate sulfate radicals (SO 4 ·− ), and produces O
·− 2
. NaOH-activated persulfate produces hydroxyl radicals (HO · ), which can oxidize chloroform. This dechlorination system showed excellent degradation efficiency for recalcitrant halogenated compounds, making it a very promising candidate for practical applications.
研究领域:
环境科学
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化学工程
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JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2012
·
IF 1.693
Jia Kang,Qing Xia,Ling-Xin Wang,Ming-Xing Du,Feng-Bao Zhang,Guo-Liang Zhang
To investigate the effects of NaOH and ethanol on the solubility of disodium decanedioate in water, the solubilities of disodium decanedioate in two aqueous solutions (aqueous NaOH solutions and aqueous ethanol solutions) were determined in a temperature range of (284 to 345) K. The solute-free mole fraction of NaOH and ethanol in the solvent mixtures extended from 0 to 0.084 and 0 to 0.472, respectively. With the increase of the mole fractions of ethanol (or NaOH) in solvent mixtures, the solubilities decreased obviously. Alcohol-out and alkali-out phenomena could be evidently observed, between which the alkali-out effect was more prominent. The determined data were correlated with the new electrolyte nonrandom two-liquid (E-NRTL) model, and the root-mean-square deviations of solubility temperature varied from (0.26 to 0.91) K.
研究领域:
化学
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物理化学
·
溶解度研究
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危险品化学品经营许可证（带存储）