Frontiers of Environmental Science & Engineering
·
2021
·Vol. 16
·期 8
·1-10
·
IF 4.357
Shen Zhichao,Zhan Lu,Xu Zhenming
Current study proposes a green regeneration method of activated carbon (AC) laden with Perfluorochemicals (PFCs) from the perspective of environmental safety and resource regeneration. The defluorination efficiencies of AC adsorbed perfluorooctanesulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorobutanesulfonate (PFBS) using three molten sodium salts and one molten alkali were compared. Results showed that defluorination efficiencies of molten NaOH for the three PFCs were higher than the other three molten sodium salts at lower temperature. At 700°C, the defluorination efficiencies of PFOS and PFBS using molten NaOH reached to 84.2% and 79.2%, respectively, while the defluorination efficiency of PFOA was 35.3%. In addition, the temperature of molten salt, the holding time and the ratio of salt to carbon were directly proportional to the defluorination efficiency. The low defluorination efficiency of PFOA was due to the low thermal stability of PFOA, which made it difficult to be captured by molten salt. The weight loss range of PFOA was 75°C–125°C, which was much lower than PFOS and PFBS (400°C–500°C). From the perspective of gas production, fluorine-containing gases produced from molten NaOH-treated AC were significantly reduced, which means that environmental risks were significantly reduced. After molten NaOH treatment, the regenerated AC had higher adsorption capacity than that of pre-treated AC.
研究领域:
环境科学
·
化学工程
✓ 已验证
DOI
高影响因子
WASTE MANAGEMENT
·
2025
·
IF 7.1
Qiang Gao,Hongyun Hu,Chan Zou,Yang Hu,Huan Liu,Xian Li,Hong Yao
Molten salt thermal treatment of solid waste is a promising way for energy recovery and pollutant removal. However, the migration of nitrogen during pyrolysis of waste tires poses a challenge for cleaner production. This study investigated nitrogen conversion pathways during waste tires pyrolysis using a binary NaOH-Na 2 CO 3 salt at 425, 500, and 575 °C. The results demonstrated that amine-N and pyrrole-N were the main N-containing species in waste tires. Compared to conventional pyrolysis, the molten salt enhanced the deamination of the amine-N while increasing levels of NH 3 and aniline. Owing to the catalytic benefits of molten salt, the C-N bond cleavage of amine-N was initiated by electron transfer involving the combination of NH 2 -Phenyl structures with Na + . The hydrocracking of Phenyl-NH-Phenyl in amine-N was facilitated by the available H radicals (or H 2 ). Furthermore, molten salt obstructed the contact of C(N) sites on the char surface, causing the suppression of HCN production. The SH radicals might be consumed by OH – ions, which disabled the formation path of benzothiazole from aniline and SH radicals. Comparatively, pyrrole-N showed limited reactivity and remained in char. This work contributes to nitrogen regulation during the molten salt treatment of solid waste.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FUEL
·
2020
·
IF 5.578
Yuhan Yang,Hongyun Hu,Fu Yang,Hua Tang,Huan Liu,Baojun Yi,Xian Li,Hong Yao
This study, for the first time, investigated the volatiles emission and thermochemical conversion mechanism of bio-waste during pyrolysis in molten salts (NaNO 3 -KNO 3 -NaNO 2 ) at 300 °C. Cations of molten salts acted as catalysts while anions participated in the pyrolysis reaction. Compared with salt-free pyrolysis, more bio-waste was decomposed in molten salts, to produce more than 14 times the mass of gaseous products and twice the mass of liquid products. Furthermore, the thermochemical conversion behavior of typical biomass constituents, i.e. cellulose, hemicellulose and lignin, was also distinguished. The results suggested that lignin was most easily pyrolyzed to form numerous liquid acids, some nitrated aromatic compounds and more CO, H 2 . In contrast, the decomposition of cellulose was certainly restricted while more significant effects of anions were found in hemicellulose cracking by generating nitrogen-containing heterocyclic rings and amines. Besides, interactions among different biomass constituents were confirmed to affect the generation of bio-waste pyrolysis products.
研究领域:
能源与环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
·
2021
·
IF 7.033
Mingzhao Guan,Qiyu Liu,Haosheng Xin,Enchen Jiang,Qiaozhi Ma
Molten salt hydrates (MSHs) are remarkable in breaking through the recalcitrant structure of microcrystalline cellulose and raw biomass. After being pretreated in 60 wt% LiBr at 130 °C for 2 h, cellulose crystallinity as well as degree of polymerization (DP) decreased. It was found that 91.3% yield of pretreated cellulose was removed from MSHs by filteration followed by being hydrolyzed into glucose with a high yield of 75.3% by dilute acid under mild reaction conditions. The pretreatment process also works on raw corn stover hydrolysis. After being pretreated at 100 °C for 5 h, 88.4% yield of cellulose in biomass was recovered and can be hydrolyzed into 54.9% yield of glucose with dilute acid. It was found that the cellulose in corn stover can be easier degraded compared with microcrystalline cellulose during MSHs pretreatment, which dues to the formation of acetic acid from hemicellulose hydrolysis. The proposed pretreatment technique presents a promising potential for glucose production from biomass in a commercial way.
研究领域:
生物化学
·
可再生能源
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Lu Tang,Huimin Yang,Huajing Wang,Yazhou Yang,Xiaoxia Wang,Gen Tang,Dawen Zeng
The abundant tunable functional groups and room-temperature sensing properties of MXenes have garnered increasing interest in the field of gas sensing. However, the majority of research has exclusively focused on the combined impact of external substances with MXenes functional groups, with limited exploration into the modulation of MXenes’ intrinsic functional groups. In this work, we successfully produced molten salt-modified Ti 3 C 2 T x MXene (M-Ti 3 C 2 T x ) with tunable oxygen-functionalized surfaces using the molten salt immersion method and employed it as a chemical resistive gas sensor to detect NO 2 at room temperature (RT). Using diverse analytical techniques, we propose the O−addition effect on the surface titanium atoms and the O−substitution effect on the edge carbon atoms, refining the existence form of –O functional groups as well as realizing the effective regulation of the intrinsic functional groups. With a high response (∼25.87%−100 ppm NO 2 , whose response value is five times higher than that of pristine Ti 3 C 2 T x ), relatively rapid response speed (∼99 s−25 ppm NO 2 ), high sensitivity (∼0.29 ppm −1 ), low detection limits (theoretical LoD is 3.3 ppm), good selectivity and long-term stability (maintain stable within 28 days) at RT, the sensor based on M-Ti 3 C 2 T x demonstrates excellent NO 2 sensing performance. To understand the sensing mechanism, density functional theory (DFT) calculations were conducted to explore adsorption behaviors. Theoretical analysis validates that M-Ti 3 C 2 T x has a stronger adsorption capacity for NO 2 (E ad = −1.149 eV) owing to the formation of covalent bond between the –O functional group and the nitrogen atom of NO 2 . The application of the molten salt can effectively modulate the intrinsic functional groups of MXenes, expanding the scope of MXenes surface modification engineering and creating new opportunities for enhancing the gas sensing capabilities of MXenes.
研究领域:
材料科学
·
气体传感技术
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Research and Technology-JMR&T
·
2020
·
IF 5.289
Chenyao Li,Shaolong Li,Yusi Che,Junyi Li,Yongchun Shu,Jilin He,Jianxun Song
The reduction mechanism of Nb(V) in molten KCl-NaCl at 1023 K was investigated by a series of electrochemical techniques such as cyclic voltammetry, square wave voltammetry and chronopotentiometry. It was found that there were three steps in the reduction of Nb(V) as Nb(V)→Nb(III)→Nb(I)→Nb, and electrochemical reaction, Nb(V)→Nb(III), is a quasi-reversible diffusion controlled process. The diffusion coefficient of Nb(V) was also obtained by cyclic voltammetry, square wave voltammetry and chronoamperometry. The relationship between current density and the square root of time shows that the nucleation of niobium belongs to the instantaneous nucleation on molybdenum electrode in molten KCl-NaCl-NbCl 5 (0.43 × 10 −3 mol/cm 3 ) at 1023 K at −3.10 V vs. Cl 2 /Cl − . Moreover, the metallic niobium was deposited on molybdenum wire by chronoamperometry, and the products were analyzed by scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX). The results showed that the metallic niobium has a high purity of 99.98%.
研究领域:
材料科学
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电化学
✓ 已验证
DOI
高影响因子
GREEN CHEMISTRY
·
2020
·Vol. 22
·期 13
·4240-4251
·
IF 9.48
Jinghua Wang,Hongyou Cui,Yong Wang,Rongrong Zhao,Yujiao Xie,Ming Wang,Weiming Yi
An efficient approach for the synthesis of levulinic acid (LA) by converting cellulose in a biphasic system consisting of molten salt hydrate (MSH), (LiCl·3H2O) and methyl isobutyl ketone (MIBK) using NbOPO4/HZSM-5 as the catalyst was reported. A series of molten salt hydrates (LiBr·3H2O, LiCl·3H2O, ZnCl2·3H2O, CaCl2·3H2O and Ca(NO3)2·3H2O) were evaluated in terms of their cellulose dissolvability and catalytic activity without any additional catalyst in the conversion of cellulose to LA. Among them, LiBr·3H2O, LiCl·3H2O and ZnCl2·3H2O were capable of dissolving and swelling cellulose and demonstrated excellent performance in cellulose conversion to LA even without any additional catalyst. High temperature favors the formation of LA while low temperature is beneficial to saccharides and 5-hydroxymethylfurfural (HMF). Using NbOPO4/HZSM-5, an efficient conversion of cellulose to LA was achieved in a biphasic system, affording a LA yield as high as 94.0%. The partition coefficient of HMF between the MIBK and LiCl·3H2O phases increased notably when the temperature was increased, proving that a biphasic solvent restrained the secondary reaction of HMF to humins. The reaction mechanism study based on the investigation of converting glucose, fructose and HMF to LA found that the side reactions of saccharides to humins are the key factors affecting the selectivity of LA in the investigated reaction system. Therefore, it is crucial to match the cellulose hydrolysis reaction with the subsequent reactions to maintain saccharides including glucose and fructose at low concentrations for highly efficient conversion of cellulose to LA.
研究领域:
化学工程
·
生物质转化
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS LETTERS
·
2018
·
IF 2.687
Jianyin Zhang,Rongli Li
Hexagonal tungsten trioxide nanoparticles were prepared using ammonium metatungstate hydrate as the precursor by a facile molten salt method. The as-prepared samples were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, X-ray photoelectron spectropy, Brunauer-Emmett-Teller, Scanning electron microscope and Transmission electron microscope. When applied for lithium-ion battery anode, it delivers 320 mAh g −1 delithiation capacities at current density of 100 mA g −1 after 130 discharge-charge cycles. The results indicate that tungsten trioxide prepared by molten salt method would be a promising anode for Lithium-ion batteries.
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
Catalysts
·
2023
·Vol. 13
·期 4
·717
·
IF 3.9
Kechen Zhang,Changxin Liu,Qiang Liu,Zheyang Mo,Dawei Zhang
Molten salts-assisted synthesis is widely used in the construction of high efficiency graphitic carbon nitride (g-C3N4) photocatalysts, and two isotypes of g-C3N4have been synthesized by such method, namely poly (heptazine imide) (PHI) and poly (triazine imide) (PTI). However, the understanding of the structural changes taking place during the molten salt process and the structure–activity relationship of g-C3N4polymorphs remain blurred. Herein, by regulating the treatment duration of g-C3N4nanosheets (melon) in molten salts, we successfully synthesized g-C3N4with phases of PHI, PHI/PTI and PTI. A continuous structural transformation induced by ions, in which melon transforms to a stable phase PTI via PHI, an intermediate state, was unveiled for the first time. In addition, results reveal that atomic configurations play a vital role in photo absorption, and charge carrier transfer and surface reaction, leading to significant differences in photocatalytic degradation. Among them, PHI with K+and cyan groups modification, as well as high crystallinity, exhibits remarkable degradation efficiency, with 90% removal of tetracycline in 10 min and 80% removal of phenol in 60 min. This study sheds light on a deeper understanding for the molten salt-assisted synthesis and provides new ideas for preparing efficient organic semiconductor photocatalysts.Keywords:graphitic carbon nitride;molten salts;structural transformation;intermediate;photocatalytic degradation
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
CARBON
·
2017
·
IF 6.337
Zhengfa Yu,Xuzhen Wang,Ya-Nan Hou,Xin Pan,Zongbin Zhao,Jieshan Qiu
In this work, we report a novel synthesis of two-dimensional (2D) N-doped mesoporous carbon nanosheets (NMCS) with high nitrogen content and developed porosity from microporous Zn-based zeolitic imidazolate framework (ZIF-8) polyhedrons in a molten salt medium. The ZIF precursors allow high nitrogen content of the NMCS while the molten salt medium leads to the formation of 2D nanosheets with mesoporosity during the pyrolysis process . The obtained NMCS exhibit highly catalytic activity in the metal-free catalytic oxidation of H 2 S toward elemental sulfur at room temperature, high breakthrough sulfur capacity is achieved over NMCS, much superior to that of ZIF-8 derived N-doped porous carbons obtained by direct pyrolysis. The transformation of three-dimensional ZIF-8 into nitrogen-doped 2D carbon nanosheets via molten salt media has great potential for the large-scale and green production of porous carbon nanosheets for highly efficient desulfurization and energy storage-conversion.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2023
·
IF 9.2
Xiang Xue,Di Gu,Yuwei Qin,Xue Lin,Qi Cui,Zixuan Li,Rui Mu,Hong Jiang,Tingting Jiang,Hongjun Wu,Baohui Wang
Herein, a solar-driven, CO 2 -fed rechargeable molten salt carbon battery is reported, which has the characteristics of capacity-tunable and noble metal catalyst-free, and continuously captures CO 2 and converts it into fuel (CO). The battery uses mixed molten carbonate as the electrolyte, which has excellent reversible electrode kinetics and superior ionic conductivity , providing the rechargeable molten salt battery excellent storage capacity and power capability. The battery is capable of continuously absorbing CO 2 from the atmosphere and converting it into carbon and carbon monoxide when it is charged. The carbon accumulates at the cathode and is used to discharge, thus producing carbon monoxide, constituting a battery capable of continuously converting carbon dioxide into carbon monoxide and storing electrical energy. The battery is perfectly matched to solar thermal and solar electricity and can be used as a novel method of storing solar energy. This paper investigates the battery performance under four electrolyte conditions. The results show that the battery has the most superior discharge performance when using a Li-Na-K-Cs-Li 2 O mixed electrolyte, maintaining ultra-high faradaic efficiency (100%) for 20 cycles. This work provides a new horizon for CO 2 conversion and solar energy utilization.
研究领域:
能源科学
·
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Energy Storage
·
2023
·
IF 9.4
Liuyi Wang,Yaoqi Huang,Linfeng Li,Yuanyuan Li,Xiaomin Cheng
Molten salts are important media for heat transfer and thermal energy storage in concentrated solar power (CSP) system, but it has drawbacks such as poor thermal conductivity and corrosive properties . This study increases the thermal energy utilization rate and expand the range of applications for phase change materials by developing a multifunctional magnetic microcapsule phase change material composed of SiO 2 @Solar Salt microcapsule and Fe 3 O 4 -functionalized carbon nanotubes (CNTs-Fe 3 O 4 ). The microcapsules have regular spherical core-shell structure and relatively small size, which improves the disadvantage of corrosiveness of molten salt and prolongs their working life. The microcapsule not only shows a good latent heat-storage capability with satisfactory phase-change enthalpies of over 88.6 J/g under an encapsulation efficiency of over 61.6 %, but also exhibits high temperature stability and cycling stability. The encapsulation of SiO 2 and introduction of the CNTs-Fe 3 O 4 high thermal conductivity enhancement phase increased the thermal conductivity of the microcapsules by approximately 53.4 % compared with pure nitrate. The microcapsules also possess superparamagnetic characteristics and photothermal conversion characteristics, both of which may be used as an additional method to improve the thermal storage efficiency. As a result, this novel material provides a promising solution for energy collecting, conversion, and storage.
研究领域:
材料科学
·
能源工程
✓ 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）