GREEN CHEMISTRY
·
2024
·
IF 9.3
Anting Ding,Chuanying Liu,Chengliang Xiao
Palladium and platinum are precious metals (PMs) used in industrial catalysis, and their green recycling is crucial but challenging. In this study, we aimed to create a novel leaching procedure for the environmentally friendly recovery of PMs using AlCl3·6H2O solution. We report here the use of a microwave-assisted AlCl3·6H2O solution to selectively recover Pd and Pt from spent catalysts. In a large-scale setting, our system can recover gram-scale Pd in a single batch. Electron paramagnetic resonance (EPR) and capture experiments revealed the hydroxyl radicals produced by proton dissociation and microwave coordination triggered the oxidative dissolution process. Microwave-assisted AlCl3·6H2O solution leaching and NaBH4 reduction recovered high-purity Pd and Pt separately. In scale-up experiments, the dissolution performance of the microwave-assisted AlCl3·6H2O solution for Pd remained almost unchanged after seven cycles. Our approach uses around 1/50 and 1/20 of the energy and chemical inputs of the conventional hydrometallurgy process, respectively. Strong acids, poisonous cyanide, and volatile organic solvents were not used during the recovery process, enabling an efficient and sustainable PM recovery process and promoting an advanced oxidation process (AOPs) technology for secondary resource recycling.
研究领域:
化学工程
·
环境科学
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产品关联
DOI
高影响因子
MOLECULES
·
2015
·Vol. 20
·期 5
·7683-7699
·
IF 2.416
Ying Zhou,Datong Wu,Pengfei Cai,Guifang Cheng,Chaobiao Huang,Yuanjiang Pan
A microwave-assisted extraction approach based on ionic liquids of different chain lengths was successfully applied to the extraction of ten flavonoid glycosides from the flowering heads ofChrysanthemum morifoliumRamat. The pretreated sample was quantified by HPLC-ESI-MSn. The main components were identified as flavonoid glycosides, including three luteolin glycosides, three apigenin glycosides, three kaempferide glycosides, and one acacetin glycoside according to the characteristics of the corresponding CID mass spectrometric patterns. Eight ionic liquids from the imidazolium family with different chain lengths, namely, 1-alkyl-3-methylimidazolium bromide, [Cnmim]Br, (n = 2–16) were studied as extraction medium in water. Results indicated that alkyl chain length had an irregular impact on the extraction efficiency. Moreover, the best extraction efficiency was achieved by 1-dodecyl-3-methylimidazolium bromide aqueous solution ([C12mim]Br). Besides the alkyl chain length of the cations, other factors influencing extraction efficiency were systematically investigated, including concentration of the IL solutions, extraction time, matrix-to-solvent ratio and irradiation power.Keywords:ionic liquids;flavonoid glycosides;microwave-assisted extraction;Chrysanthemum morifoliumRamat
研究领域:
植物化学
·
分析化学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF ELECTRONIC MATERIALS
·
2018
·Vol. 47
·期 12
·7497-7504
·
IF 1.566
Zheng Jingxia,Wang Junli,Wang Yaling,Yang Yongzhen,Liu Xuguang,Xu Bingshe
A one-pot microwave-assisted hydrothermal approach was developed to quickly synthesize yellow fluorescent carbon dots (CDs) using o -phenylenediamine and urea as raw materials. The optimized reaction temperature of 140°C and reaction time of 10 min were adopted to synthesize the CDs with photoluminescence quantum yield of 4.23%. The as-prepared CDs exhibit yellow fluorescence ( λ em ∼ 563 nm) and an excitation-independent PL emission in the region of 440–700 nm. The CDs were combined with a blue chip ( λ ex = 420 nm) to fabricate white light-emitting diodes (WLEDs) and realize white light emission. The WLED has the color coordinates of (0.30, 0.30) and the correlated color temperature of 7915 K, which is suitable for office and outdoor illumination. The results demonstrate that as-obtained CDs can be a promising candidate as yellow-emitting phosphors for WLEDs.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMOSPHERE
·
2022
·
IF 8.943
Wang Jianle,Zeng Gongchang,Deng Hong,Liu Xueming,Zhao Dongye
Remediation of soil contaminated by mixed heavy metals and metalloids has been a major challenge in the global environmental field. To address this critical issue, we tested a new technology for simultaneous immobilization of lead (Pb) and arsenic (As) in a field contaminated soil using a microwave-assisted FeSO 4 ·7H 2 O treatment process. The process was able to rapidly reduce the TCLP-based leachability of Pb from 12.74 to 0.1 mg L −1 and As from 2.704 to 0.002 mg L −1 (MW power = 800 W, Irradiation time = 20 min, and FeSO 4 ·7H 2 O = 4 wt%). The effects of FeSO 4 ·7H 2 O dosage, microwave power, and irradiation time were determined and optimized. After 365 days of curing under atmospheric conditions, the TCLP-leached concentration of Pb and As in the treated soil remained below the regulatory limits of 0.1 and 0.002 mg L −1 , respectively. The microwave irradiation promoted the formation of insoluble PbSO 4 (s) and Fe 3 (AsO 4 ) 2 ·8H 2 O(s), resulting in the long-term stability of Pb and As in the soil. The technology offers an effective alternative for remediation of Pb- and/or As-contaminated soil and groundwater.
研究领域:
环境科学
·
污染控制技术
✓ 已验证
DOI
PubMed
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
CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2015
·Vol. 31
·期 2
·175-178
·
IF 0.875
Lü Yang,Yang Min,Yang Bin,Liu Wei,Zhang Hongdan,Zhao Xudong,Liu Xiaoyang
SrWO 4 :Eu 3+ nanowires were synthesized at 160 °C within 10 min via a microwave-assisted hydrothermal method. In examining the influences of synthesis temperature and reaction time on the morphology of nanowires, it was found that any temperatures and reaction time except 160 °C and 10 min gave rise to poorer morphologies under otherwise equal conditions. The synthesized nanowires were characterized by means of X-ray diffraction(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM), high-resolution transmission electron microscopy(HRTEM), energy dispersive X-ray(EDX) and Raman spectrometry, respectively. The results suggest that the samples are homogenous and dispersive single phase nanowires. The photoluminescence properties of the nanowires were determined with a spectrofluorometer. Two obviously sharp peaks at 395 and 464 nm and a broad peak centered at 290 nm were found in their excitation spectrum. Under excitation at 395 and 464 nm, the 5
D
0 → 7
F
2 transition is the dominant process which means Eu 3+ ion is located at a low symmetry site, while the 5
D
0 → 7
F
1 transition dominates under the excitation at 290 nm, showing a highly symmetric field around the Eu 3+ ion, which indicates the presence of the two local Eu 3+ environments.
研究领域:
材料科学
·
纳米技术
·
光学材料
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稀土化学
·
无机合成
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Keke Guan,Wen Lei,Honghong Wang,Xuefeng Liu,Jin Luo,Jianghao liu,Quanli Jia,Haijun Zhang,Shaowei Zhang
In this work, Ti 3 AlC 2 powders with high purity were prepared by microwave-assisted molten salt method (MA-MS). The synthesis parameters (such as raw materials ratio, heating temperature and reactant materials) and the formation mechanisms were systematically investigated. The results indicate that Ti 3 AlC 2 powders with a high purity up to 98.5% are prepared using TiH 2 /Al/1.8TiC mixture as reactant materials, and NaCl–KCl as molten salt by microwave-assisted heating at 1050 °C for 30 min. Compared with traditional heating methods, both the synthesis temperature and holding time of highly pure Ti 3 AlC 2 powders synthesized in this work are much milder. This high-efficiency synthesis approach could be ascribed to the synergistic effect of molten salt and microwave heating. Moreover, the TiH 2 –Al–TiC starting material is more suitable for the rapid synthesis of Ti 3 AlC 2 powders with high purity via present microwave-assisted molten salt method than that TiH 2 –Al–C.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Analytical Methods
·
2012
·Vol. 4
·期 4
·1012-1018
·
IF 1.547
Xiaojie Liu,Yuzhi Wang,Jinhuan Kong,Chan Nie,Xiao Lin
Eight types of ionic liquid (IL) were synthesized in this paper, and ionic liquids-based microwave-assisted extraction (ILs-MAE) technique was used to extract quercetin from the Chinese herbal medicine Toona sinensis. Several significant operating parameters were optimized by a series of single factor experiments and orthogonal design L9 (34) experiments in this work. Compared with liquid-based maceration extraction (ILs-ME), liquid-based heat extraction (ILs-HE) and liquids-based ultrasound-assisted extraction (ILs-UAE), the optimized approach of ILs-MAE technique cost the shortest time but afforded the highest extraction amount. Moreover, reversed phase high performance liquid chromatography (RP-HPLC) with ultraviolet detection (UV-DAD) was employed for the analysis. The results show that the amount of quercetin extracted by [Bmim]Br was 182.78 mg g−1 with RSD 1.02%. The developed approach is linear between concentrations from 15.20 mg L−1 to 213.2 mg L−1 of quercetin and the regression coefficient (R) was 0.9992. The recoveries of quercetin extracted by these four methods were 95.07%–105.8% with RSDs lower than 3%. Furthermore, the change of the microstructure and chemical structure of the sample before and after different extraction procedures were researched, respectively. Because of the remarkable dissolving capacity of ILs aqueous solution and the obvious destruction on sample surface microstructures during ILs-MAE process, ILs-MAE technique got the highest extracted amount. With the help of LC-MS, we can further confirm that Toona sinensis do contain the active ingredient of quercetin and ILs had no interference of quercetin.
研究领域:
药学
·
分析化学
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DOI
高影响因子
Journal of Natural Fibers
·
2023
·
IF 3.5
Boya Li,Kai Nie,Linlin Li,Gang Fu,Chunguo Liu,Shouwu Gao,Guangting Han,Tao Zhao,Wei Jiang
The Sesamum indicum bast contains more hemicellulose, lignin, and flaky parenchymal cells than the commonly used ramie bast, which are rigid for the degumming process. We explored a facile and greener method by using glycolic acid microwave-assisted treatment combined with alkaline treatment to effectively and low-cost prepare the high-quality Sesamum indicum single fibers. The chemical and physical properties of fibers were analyzed by chemical composition analysis, SEM, FTIR, XRD, TG, and GPC analysis. The residual gum content was decreased from 34.4% to 4.2%, resulting in a cleaner micro-surface of the Sesamum indicum fibers with increased cellulose crystallinity (75.2%–82.5%) and thermal stability (357°C–365°C). The fiber fineness (2.5 dtex) and breaking tenacity (4.9 cN/dtex) of the fibers produced by the novel treatment method exhibited the same level compared with the traditional two-step alkaline fibers. Besides, both the consumption of water and the chemicals was decreased compared with traditional degumming. This work provided a novel green and facile degumming method for processing the natural bast fibers.
研究领域:
材料科学
·
植物学
✓ 已验证
DOI
高影响因子
Arabian Journal of Chemistry
·
2021
·
IF 5.165
Zaizhi Liu,Hualan Li,Yanlong Qi,Zheng Zhu,Dai Huang,Ke Zhang,Jun Pan,Lan Wen,Zhengrong Zou
Cinnamomum camphora is a notable tree species of great significance to human beings. Proanthocyanidins (PCs) were separated from C. camphora leaves using microwave assisted extraction (MAE) method. Four variables of the MAE procedure were studied using the Box-Behnken design of response surface method. The results demonstrated that the optimal extraction conditions were: ethanol concentration of 77%; liquid/solid ratio of 20 mL/g, microwave time of 18 min, and microwave power of 530 W to achieve an actual yield of 81.56 ± 2.03 mg/g for C. camphora PCs. Extraction kinetic study results indicated that MAE is the most efficient method for C. camphora leaf PCs extraction under the obtained conditions in comparison to the reference methods (heat reflux extraction, ultrasound extraction, and Soxhlet extraction), by which the highest yield of PCs and the volumetric mass transfer coefficient were obtained in the shortest extraction time. Antioxidant activity study revealed that C. camphora leaf PCs could be used as a natural alternative to the synthetic commercial antioxidants.
研究领域:
植物化学
·
药理学
✓ 已验证
DOI
高影响因子
Molecular Catalysis
·
2024
·
IF 3.9
Fukun Li,Ronghe Yang,Jinhang Dai,Hanyue Deng,Junjun Shi,Wucheng Xie,Juanhua Kong,Tingwang Guo
Biomass upgrading, which supplies important biomaterials, chemicals and fuels, is considered as an efficient way to realize the goal of carbon neutralization. Recently, γ-valerolactone (GVL) has gained increasing attention due to its wide applications. In this work, a novel protocol of microwave-assisted cascade catalytic upgrading of α-angelicalactone (α-AL) to GVL over metal triflate using alcohol as the hydrogen donor was proposed. The yield of GVL production from α-AL upgrading is strongly influenced by the Lewis acid strength of the metal triflate and the reduction potential of the employed alcohol. Among all tests, Sc (OTf) 3 showed the best catalytic performance in isopropanol media, giving 96.4 % GVL yield and 100 % α-AL conversion at 433 K within 3.0 h. Meanwhile, kinetic study indicated transfer hydrogenation of isopropyl levulinate to isopropyl 4-hydroxyvalerate was the rate-limited step with the apparent activation energy of 94.5 kJ/mol. This Sc (OTf) 3 catalyst was highly stable and could be reused for five cycles by simple vacuum distillation. In a word, this work provides an alternative for GVL production from biomass upgrading.
研究领域:
生物质化学
·
催化科学
·
可再生资源
✓ 已验证
DOI
高影响因子
MOLECULES
·
2019
·Vol. 24
·期 15
·2770
·
IF 3.06
Yunchang Fan,Zeyu Niu,Chen Xu,Lei Yang,Tuojie Yang
Rheum palmatumL. (R. palmatumL.) is a traditional Chinese herb and food, in which rhein and emodin are the main bioactive components. The extraction of the two compounds fromR. palmatumL. is, thus, of great importance. In this work, protic ionic liquids (PILs) were applied in the microwave-assisted extraction (MAE) of rhein and emodin fromR. palmatumL., which avoids the toxicity of organic solvents. The results of the present study indicate that PILs possessing higher polarity exhibit higher extraction ability due to their stronger absorption ability for microwave irradiation. Compared with conventional solvents, such as methanol, trichloromethane, and deep eutectic solvents (DESs), the PIL, 1-butyl-3-himidazolium methanesulfonate ([BHim]MeSO3) reported herein is more efficient. The selected extraction conditions of liquid–solid ratio, microwave irradiation time, microwave irradiation power, and PIL concentration were 40 g·g−1, 50 s, 280 W, and 80%, respectively. Under the selected conditions, the extraction yields of rhein and emodin were 7.8 and 4.0 mg·g−1, respectively. These results suggest that PILs are efficient extraction solvents for the separation of active components from natural products.Keywords:microwave-assisted extraction;protic ionic liquids (PILs);polarity;Rheum palmatumL.
研究领域:
中药学
·
分析化学
✓ 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）