ACS Sustainable Chemistry & Engineering
·
2023
·
IF 8.4
Handong Jiao,Mengjun Liu,Zhe Wang,Manpeng Lin,Zhaoliang Qu,Jianxun Song,Shuqiang Jiao
Molten salt electrorefining is expected to be a powerful technology for upcycling titanium scrap because of its robust ability of removing impurities. However, realizing the stable operation of electrorefining, for example, the current efficiency of the anode and the cathode is still a key challenge from the viewpoint of industrial applications. Here, we study titanium’s anodic dissolution and cathodic deposition processes via a direct three-dimensional visualization method based on a computed tomography technology under high-temperature operational conditions. Real-time quantitative results show that the current efficiency is obviously affected by the concentration of titanium ions in the melt. Visual analysis of the local dissolution rate and the curvature of the titanium anode at different electrolysis stages reveals the kinetic origin of the concentration-induced current efficiency changes, which arise from the priority of the side reactions being dependent on the concentration of titanium ions. Finally, we show that employing the high concentration and single existence forms of titanium ions is an effective strategy to prevent the side reactions and improve the current efficiency. This work provides a fresh and fundamental understanding of the side reactions occurring at the interface of electrodes and is significant for facilitating the stability of electrorefining engineering of titanium.
研究领域:
材料科学
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冶金工程
✓ 已验证
产品关联
DOI
高影响因子
JOM
·
2021
·Vol. 74
·期 1
·195-202
·
IF 2.474
Xia Longgong,Yu Zhiqian,Xu Gexiong,Liu Zhihong
Arsenic monitoring is a critical issue in the copper-making industry, and its removal at the fire-refining stage is important. However, arsenic is poorly removed in the traditional fire-refining practices. A new “As enrichment—targeted oxidation—slag modifying” process is proposed and experimentally studied in this work. The results showed: (1), arsenic can be readily enriched by the Cu-Pb liquid alloy phase which helps the subsequent oxidation removal; (2), SiO 2 and NaHCO 3 were used as fluxes in the four-phase fire-refining process (Cu phase/Cu-Pb alloy phase/slag phase/gas phase). Fe, S, and Pb could be easily removed, and the removal efficiencies of As, Sb, and Bi were clearly improved; and (3) when treating a crude copper with 0.45 wt.% As under optimized conditions, 93.6% Cu was recovered, and the removal efficiencies of As, Sb, and Bi were 33.2%, 57.7%, and 48.6%, respectively.
研究领域:
冶金工程
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
Food Quality and Safety
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2022
·
IF 3.949
Cai Chenggang,Chang Guoli,Zhang Nianhua,Wang Junlin,Wang Liyuan,Wu Pinggu,Yang Dajin
ObjectivesPolycyclic aromatic hydrocarbons (PAHs) and 3-monochloropropane-1,2-diol ester (3-MCPDE) were studied in camellia oil. It is important to study the changes in the content of PAHs and 3-MCPDE at different refining stages (from crude oil to the final refined oil product) to elucidate the influence of the refining procedures on their change.Materials and methodsThe PAHs and 3-MCPDE in camellia oil from different refining stages (from crude oil to the product) of a plant were analyzed by gas chromatography–mass spectrometry and calculated by the internal standard method.ResultsThe overall PAH content was (79.64±2.43) µg/kg in crude camellia oil. After refining treatment, the PAH content decreased to (18.75±0.55) µg/kg. The 3-MCPDE content increased during the refining process from 0 mg/kg in the crude oil to 4.62 mg/kg in the refined oil product.ConclusionsThis is the first study to simultaneously monitor changes in both PAH and 3-MCPDE contents during the production of camellia oil. These results confirmed the effectiveness of the refining method on PAH removal and the increase in 3-MCPDE at high temperature. It is suggested that novel processing methods or refining parameters need further optimization to decrease the overall concentrations of PAHs and 3-MCPDE in camellia oil.
研究领域:
食品科学
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环境毒理学
✓ 已验证
产品关联
DOI
高影响因子
BIOTECHNOLOGY AND BIOENGINEERING
·
2022
·Vol. 119
·期 7
·1903-1915
·
IF 4.395
Niling He,Jia Jia,Zhongyang Qiu,Chun Fang,Gunnar Lidén,Xiucai Liu,Jie Bao
Cyclic chiral lactide is the monomer chemical for polymerization of high molecular weight polylactic acid (PLA). The synthesis of cyclic l -lactide starts from poly-condensation of l -lactic acid to a low molecular weight prepolymer and then depolymerized to cyclic l -lactide. Lignocellulose biomass is the most promising carbohydrate feedstock for lactic acid production, but the synthesis of cyclic l -lactide from l -lactic acid produced from lignocellulose has so far not been successful. The major barriers are the impurities of residual sugars and inhibitors in the crude cellulosic l -lactic acid product. Here we show a successful cyclic l -lactide synthesis from cellulosic l -lactic acid by lignocellulose biorefining with complete inhibitor removal and coordinated sugars assimilation. The removal of inhibitors from lignocellulose pretreatment was accomplished by biodetoxification using a unique fungus Amorphotheca resinae ZN1. The nonglucose sugars were completely and simultaneously assimilated at the same rate with glucose by the engineered l -lactic acid bacterium Pediococcus acidilactici . The l -lactic acid production from wheat straw was comparable to that from corn starch with high optical pure (99.6%), high l -lactic acid titer (129.4 g/L), minor residual total sugars (~2.2 g/L), and inhibitors free. The cyclic l -lactide was successfully synthesized from the regularly purified l -lactic acid and verified by detailed characterizations. This study paves the technical foundation of carbon-neutral production of biodegradable PLA from lignocellulose biomass.
研究领域:
生物化学
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可再生资源与环境工程
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2024
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IF 13.3
Yang Wang,Qiaoling Liu,Chuanyu Yan,Guoyong Song,William S. Price,Gang Zheng,Allan M. Torres,Zhimin Xue
High-value utilization of lignocellulose and its components is generally constrained by the pretreatment efficiency and the structural robustness of fractionated components. Harsh pretreatment conditions can promote pretreatment efficiency but also cause serious condensation of lignin structure, thus inhibiting the depolymerization of lignin into valuable chemicals. Herein, we designed a novel deep eutectic solvent (DES) composed of pyridine hydrochloride, ethylene glycol, and AlCl 3 for the pretreatment of lignocellulose. In the developed DES, the lignocellulose could be efficiently fractionated into the natural lignin derivatives with satisfactory hydrogenolysis reactivity and the carbohydrate fraction with high enzymatic digestibility owing to the synthesized DES having adjustable hydrogen-bond acidity, high affinity for lignin, and good protection role on lignin structure. After being pretreated under a mild fractionation condition (70°C, 6 h), a promising delignification ratio of 70.4 % was obtained for poplar, and the extracted lignin exhibited native substructure with well-preserved β-O-4 linkages (42.1 per 100 aromatic units), abundant hydroxyl groups content (4.97 mmol/g), and high molecular weight (5643 g/mol). These structural features contributed to the conversion of the obtained lignin into aromatic monomers with a high yield (27.4 %). Besides, the pretreated residue could be efficiently converted into glucose with a yield of 88.2 % due to the abundant hydroxyl groups of lignin in the cellulose-rich residues. Remarkably, comprehensive studies of lignin structural evolution during pretreatment revealed that the structure-controllable lignin could be effectively isolated by modulating the hydrogen-bond acidity of DESs. This work proposed a mild and efficient lignin-first biorefinery approach that was conducive to the integrated valorization of lignocellulose.
研究领域:
生物质能
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化学工程
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
CARBOHYDRATE RESEARCH
·
2024
·
IF 2.4
Yulong Chang,Yongtai Wang,Yimo Feng,Xiangling Zhu,Hongjun Zang
The “shell biorefinery,” which valorizes the shell waste chitin into fine chemicals, has developed rapidly in recent years. Herein, we present a novel base-free heteropolyacid-catalyzed oxidation method for the transformation of chitin biomass into organic acid. After a series of optimization experiments, a 5.93 % yield of formic acid and 25.09 % yield of acetic acid were achieved in the presence of 0.5 equivalent of Mo–V–P heteropolyacids (H 4 PMo 11 VO 40 ·2H 2 O) and air at 180 °C under hydrothermal conditions for 4 h. Meanwhile, we have demonstrated that the Keggin-type heteropolyacid catalysts are capable of efficiently converting microcrystalline chitin into organic acids. The synthesized heteropolyacids are well characterized with FT-IR, XRD, ICP-AES, and TGA. The possible reaction pathway was speculated accordingly. This method offers several advantages, including readily available raw materials, simple operation, and relatively higher yield.
研究领域:
生物化学
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可持续化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Sustainable Chemistry & Engineering
·
2022
·
IF 9.224
Changliu Xiang,Sijun Zhu,Jinbo Song,Yougang Li,Tao Luo,Cong Chang,Junjie Qu,Shenghai Yang,Changhong Wang,Yongming Chen
The conventional electrorefining process of crude lead (Pb)─employing a bone glue (BG)- and calcium lignosulfonate (CL)-synergistically assisted fluosilicic acid (H2SiF6) system─suffers the undesired environment burden caused by the high saturated vapor pressure and low stability of H2SiF6. Herein, we propose an additive-assisted methanesulfonic acid (MSA) system for green and efficient electrorefining of crude Pb based on the low volatility and high stability of MSA. Combinations of MSA with additives are evaluated and screened using photographic images, SEM observations, XRD, white light interference, etc. The electrochemical analysis of cyclic voltammetry and chronoamperometry elucidates the Pb deposition behavior in the Lugalvan BNO12-assisted MSA system, in which a three-dimensional nucleation model is applicable. Using MSA as the solvent and β-naphthol ethoxylate (Lugalvan BNO12) as the assisted additive, the bench-scale operation of crude Pb electrorefining experimentally achieves an electric energy requirement (W) of 87 kWhe/t Pb and a cathodic current efficiency (η) of 99.6%. This is very competitive with the W of 120 kWhe/t Pb and η of 95.0% for the BG-CL-assisted H2SiF6 system. Also, the bench-scale operation obtains a plat and dense deposit sample with a Pb purity of >99.99%. The distribution behavior of elements shows that most of the Pb element is recovered in the form of the cathodic Pb, elements Sn, Zn, and Fe mainly accumulate in the electrolyte, and elements As, Sb, Bi, Ag, and Cu remain in the anode slime. This work opens new directions for more technically and economically feasible Pb electrorefining.
研究领域:
冶金工程
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环境科学
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2019
·
IF 5.107
Yusheng Yang,Chaoqun Lan,Lingyun Guo,Zhuoqing An,Zengwu Zhao,Baowei Li
Tens of thousands of tons of rare-earth permanent magnet (REPM) wastes are produced worldwide every year. The recovery of rare-earth elements from the wastes can effectively reduce the exploitation of rare-earth minerals. The recovery of neodymium and praseodymium from a REPM waste is investigated by electrolysis in molten LiF-CaF 2 where no anode gas releases, making the process environmentally attractive. Neodymium and praseodymium are selectively oxidized from the REPM waste and transformed into rare-earth ions. To facilitate the oxidation of rare-earth elements inside the REPM waste, we intended to make REPM electrode form channels by oxidation of Nd-Pr and Nd 2 Fe 14 B alloys. By analyzing the microstructure of REPM electrode after forming channels, it can be found that the channels provide continuous transport access of the electrolyte to the inside of the REPM electrode. The separation rates of Nd and Pr increase with increasing current, while the rate of oxidation reaction is proportional to current. In addition, the oxidation of Fe initially occurs at the inside of the REPM electrode where rare-earth elements have been first depleted. The separated rare-earth ions are directly prepared as rare-earth metals at the cathode by electrolysis, leaving the porous Fe 2 B alloy and metallic Fe.
研究领域:
材料科学
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环境工程
✓ 已验证
产品关联
DOI
高影响因子
Waste and Biomass Valorization
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2023
·
IF 3.2
Li Zhi-jian,Wang Wei,Jiang Long-jin,Chang Zhi-dong,Ma Xi-ping,Luo Xin
In order to extend the duration of the electrolyte solution in which copper granules recovered from waste printed circuit board are refined through electrolysis to obtain copper foil with high purity and which is contaminated by the accumulation of metallic impurities along with the refinery of waste printed circuit board, the leaching and electrowinning processes are used to pretreat the copper granules. The effects of impurities of copper granules as well as H 2 SO 4 mole ratio, leaching temperature, liquid-solid ratio, and operation time on the removing efficiencies of Zn, Sn, Fe and Al, were studied. The results showed that more than 95% of impurities can be removed when the mole ratio of impurities to H 2 SO 4 was 1:4, the temperature was 70 °C, the liquid-solid ratio was 20 mL/g, along with the leaching time of 180 min. After 1440 min electrolysis of the pretreated granules with the electric current density of 40 mA/cm 2 , the purity of refined copper foil maintained at 99% in contrast with 95% which copper granules are without pretreatment. The maximal concentration of the accumulated ions of impurities is less than 60 mg/L, which suggests that sulfuric acidic pretreatment is a promising approach to increase the duration of the electrolyte solution.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
·
2025
·
IF 3.1
Chen Shi-Liang,Lu Chang,Yan Yu-Chi,Guo Zhi-Peng,Fan You-Qi,Zhao Wei-Cheng,Wang Xin,Guan Xiu-Tao,He Shi-Wei,Zheng Jia-Le
Silver is the most difficult non-copper impurity element to be purified and removed during the preparation of high-purity copper products by electrolysis. This is primarily due to the unpredictable behavior of trace amounts of silver during electrolysis. As a result, current methods for reducing silver content in cathode copper are limited and often ineffective, with silver levels remaining above 8 ppm. This work examines the cathodic behavior of Ag + during copper electrolysis using thermodynamic and kinetic theoretical calculations, variable experiments, and a detailed analysis of the trace Ag phase in copper cathode. Experimental findings indicate that the concentration of Ag + in the electrolyte is the primary determinant of silver content in cathode copper, specifically, the silver content in copper cathode rises dramatically with increasing the concentration of Ag + in the electrolyte. Under the condition of current density 300 A/m 2 , T = 63 °C, Ag + concentration of 0.01 mg L −1 , the silver content in copper cathode diminishes by 81.43 pct from 8.51 to 1.41 ppm. Combining electrochemical tests (cyclic voltammetry and square wave voltammetry) with scanning electron microscopy, an intriguing revelation has emerged. Following electromigration, diffusion, desolvation, and electroreduction, the silver most likely embeds into the copper deposition layer with the occurrence state of Cu 9 Ag solid solution alloy, rather than the traditional belief that silver exists as an independent silver element. This study contributes to a fundamental understanding of the underlying causes of the difficulty in removing silver from copper cathode, and provides inspiration for the development of new methods to improve the purity of electrolytic copper and to reduce the silver lost therein. Graphical
研究领域:
冶金学
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电化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2024
·
IF 3.5
Dong Weinan,Qiu Xuehong,Zhao Weisong,Guo Bao,Jiang Kaixi,Chiou Mong-Feng,Li Anpeng
In this study, the occurrence state and distribution characteristics of gallium (Ga) in zinc refinery residue were investigated by dilute acid pre-washing to enrich Ga in zinc refinery residue, followed by silane coupling agent pretreatment and epoxy resin curing, and then analyzed using scanning electron microscopy, focused ion beam micro-slicing technique and transmission electron microscopy. The acid washing increased the mass ratio of Ga from 0.92% to 2.12%. Energy-dispersive spectroscopy and select area electron diffraction revealed that Ga occurred as tiny ring-like particles of gallobeudantite (a Pb-jarosite) that intimately envelop the previously formed K-jarosite fine-grained inclusions. Density functional theory calculations showed that the interplanar spacings of the new phase formed after Ga substitution for Fe in Pb-jarosite (3.413 Å and 5.505 Å) were in good agreement with the actual measured values, further confirming that Ga substitution for Fe in Pb-jarosite was achieved. The kinetical model explains the formation of multiple phases during precipitation in the treatment of zinc leaching solution. Compared to existing studies, this work reveals the spatial distribution of gallium with higher resolution and jointly determines the gallium-containing phases through experimental analysis and simulation calculations. This microanalytical method enhances the understanding of Ga species formation during zinc refining, aiding in their distribution control and process optimization. Graphical abstract
研究领域:
材料科学
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冶金工程
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF FOOD COMPOSITION AND ANALYSIS
·
2024
·
IF 4
Mengru Kong,Yanli Du,Xiaodie Chen,Ruixin Cai,Jianhua Xie,Mingyue Shen
Trans fatty acids (TFAs) are formed in refined linseed oil during the deodorization step. Effects of deodorization on TFA formation in vegetable oils have been intensively investigated. However, the role of refining process (degumming, neutralization, bleaching) before deodorization on TFA formation in the deodorization step remains unclear. In this study, TFA generation potential in linseed oils refined by different ways of degumming, neutralization, bleaching was evaluated, and changes in their quality indexes were also measured. Results showed that adequate refining could improve the quality of linseed oil, while inadequate neutralization or bleaching induced more TFA formation during the deodorization step, suggesting that pigments or free fatty acids in linseed oils might promote TFA formation. Meanwhile, spiked experiments, in which partly refined linseed oils were spiked with pigments or α-linolenic acid, confirmed that pigments or free fatty acids in linseed oils induced the isomerization of unsaturated fatty acids. This study demonstrated that TFA formation in refined linseed oils could be mitigated by optimizing refining processes before deodorization, and also provided theoretical basis for oil refining industry to control the oil quality.
研究领域:
食品科学
·
营养学
✓ 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）