ACS Catalysis
·
2022
·
IF 13.7
Dongmiao Li,Jinni Shen,Jiangjie Zhang,Yao Chai,Yanyu Xie,Chengwei Qiu,Mengmeng Ni,Yuanhui Zheng,Xuxu Wang,Zizhong Zhang
The development of direct conversion for selective functionalization of inert methane plays an important role in the chemical sciences. Here, we report a photocatalytic approach to successfully convert methane into methyl chloride over NaTaO3 photocatalyst using an alkali chloride solution as the chlorine source under ambient conditions, which can overcome disadvantages of toxicity and corrosiveness in the traditional chlorination of methane. Various noble metals and oxide cocatalysts (Pt, Pd, Au, Ag, and Ag2O) and different chloride ion solutions (NaCl, KCl, LiCl, MgCl2, BaCl2, CaCl2, CuCl2, FeCl3, ZnCl2, etc.) are investigated to optimize the photocatalytic chlorination processes. Ag2O/NaTaO3 is the best photocatalyst, giving the maximum CH3Cl yield of 152 μmol g–1 h–1 in aqueous NaCl solutions and an apparent quantum yield of 7.2% under 254 nm monochromatic light irradiation. The target product CH3Cl is verified to be formed by a direct combination of the photoinduced species •CH3 and •Cl on the Ag2O surface. This work provides a meaningful approach for the conversion of methane into chloromethane under normal conditions.
研究领域:
化学科学
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环境科学
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产品关联
DOI
高影响因子
BIORESOURCE TECHNOLOGY
·
2025
·
IF 9
Weiqi Zhang,Xin Kong,Linlin Bo,Delin Yin,Zhichun Zhang,Xiaojun Fan,Hongping Chen,Jin Yuan
Zeolitic imidazolate framework-8 (ZIF-8) has been widely employed for carbon dioxide (CO 2 ) and methane (CH 4 ) separation, and CO 2 adsorption and storage owing to its high porosity and tunable pore structure. However, its potential to enhance CO 2 -to-CH 4 conversion by grasping CO 2 in hydrogenotrophic methanogenic systems, thereby increasing CH 4 percentage in biogas, remains unexplored. This study synthesized ZIF-8 material and applied it in a biological biogas upgrading system. The results indicated that the CO 2 -to-CH 4 conversion rate was maximized in the system with 0.75 g/L of ZIF-8 added. Over a single reaction cycle (5 days), the CH 4 proportion increased from 60 % to 97 %. Furthermore, in continuous operation over three reaction cycles, the ultimate CH 4 proportion in this reactor consistently exceeded 95 %, meeting the standards of biomethane. The pathway analysis revealed that the ZIF-8 introducing could increase abundance of hydrogenotrophic methanogens and facilitated the transition of metabolic pathway from acetotrophic to hydrogenotrophic methanogenesis.
研究领域:
环境科学
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微生物学
·
材料科学
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DOI
PubMed
高影响因子
JOURNAL OF SEPARATION SCIENCE
·
2017
·Vol. 40
·期 17
·3414-3421
·
IF 2.557
Jie Zhou,Jie Xu,Xiangyuan Zheng,Wenyuan Liu,Feng Zheng
Methanesulfonic acid is routinely used in pharmaceuticals but can contain potentially genotoxic impurities such as methyl methanesulfonate and ethyl methanesulfonate. The aim of this study was to develop a simple high-performance liquid chromatography with ultraviolet detection method for determining methyl methanesulfonate and ethyl methanesulfonate in methanesulfonic acid. Samples (250 mg) in water/acetonitrile (200 μL) were first combined with 10.0 mol/L sodium hydroxide solution (270 μL). Then they were mixed with 2.0 mg/mL N , N -diethyldithiocarbamate (500 μL), diluted to 5 mL with N , N -dimethylacetamide and allowed to react at 80°C for 1 h. The derivatives were analyzed using gradient high-performance liquid chromatography with ultraviolet detection (277 nm) and structurally elucidated by liquid chromatography with mass spectrometry. With acetonitrile/5 mmol/L ammonium acetate solution as the eluent and 1 mL/min as the flow rate on a C18 column, the derivatives were eluted at 10.6 and 14.8 min. Good linearity (correlation coefficients > 0.999) and low limits of quantitation (0.6 ppm) were obtained. The recoveries were in the range of 80–115% with relative standard deviation < 5.0%. Finally, the established method was successfully used for the determination of methyl methanesulfonate and ethyl methanesulfonate in methanesulfonic acid.
研究领域:
分析化学
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药学
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产品关联
DOI
PubMed
高影响因子
PROCEEDINGS OF THE COMBUSTION INSTITUTE
·
2024
·
IF 5.3
Qilong Fang,Jun Fang,Yi Zhang,Jianguo Zhang,Tianyou Lian,Wei Li,Yuyang Li
Oxymethylene ethers (OMEs) have received great attention due to their carbon-neutral nature and advantageous properties as alternative transportation fuels or fuel additives. Previous studies focused on the combustion of linear OMEs with the chemical formula of CH 3 O(CH 2 O) m CH 3 ( m ≥ 0), while a deep understanding of the combustion of branched OMEs with the chemical formula of CH 3 OCH 3- n (OCH 3 ) n (0 ≤ n ≤ 3) is still absent. In this work, the flow reactor pyrolysis of dimethoxymethane (DMM, n = 1), trimethoxymethane (TMM, n = 2), and tetramethoxymethane (TeMM, n = 3) is investigated using gas chromatography, with special attention given to the multi-sidechain effects on the pyrolysis chemistry. A pyrolysis model of branched OMEs is developed and validated against the new pyrolysis data. Modeling analysis is performed to provide insights into the pyrolysis chemistry of the three branched OMEs and the multi-sidechain effects. Unimolecular decomposition and H-abstraction reactions are found to be two major types of fuel decomposition pathways, with the former dominating TMM decomposition, the latter dominating DMM decomposition, and both contributing almost equally to TeMM decomposition. Sensitivity analysis shows that C O bond dissociation is the most sensitive reaction to fuel decomposition in DMM pyrolysis, while methanol elimination is the most sensitive reaction in TMM and TeMM pyrolysis. Among the three fuels, DMM has the lowest pyrolysis reactivity and produces the least abundant methanol. In contrast, TMM is observed with the highest pyrolysis reactivity and produces the most abundant methanol. Theoretical calculations reveal that TMM and DMM have the lowest and highest energy barriers of methanol elimination reactions, which determines the order of their pyrolysis reactivities and methanol formation trends. As a result, DMM pyrolysis occurs at higher temperature regions where the C O bond dissociation and H-abstraction reactions are preferred, while TMM pyrolysis occurs at lower temperature region where methanol elimination dominates.
研究领域:
能源科学
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化学工程
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Wenfeng Han,Jinchao Wang,Lulu Chen,Luteng Yang,Shucheng Wang,Miao Xi,Haodong Tang,Wucan Liu,Weiyu Song,Jianjun Zhang,Ying Li,Huazhang Liu
Trifluoromethane is one of the most potent and stable greenhouse gases with global warming potential of 14,800 times higher than CO 2 (100-year time horizon). At present, it is destroyed by incineration or plasma at temperatures above 1200 K. For the first time, this work report that CHF 3 can be reverted to HCFC-22 via the intermolecular Cl/F exchange reaction of CHF 3 with CHCl 3 over AlF 3 catalyst under moderate conditions. As CHF 3 is produced during the manufacture of HCFC-22 via the fluorination of CHCl 3 in liquid phase, no additional feedstock and products are involved for the treatment of CHF 3 in this proposed process. At 593 K and atmospheric pressure, CHF 3 conversion levels of about 18%–20% are achieved and no significant deactivation is observed following time on stream of 100 h. In addition, the catalytic reaction mechanism is proposed. According to the experiments and DFT calculation, the intermolecular Cl/F exchange reaction of CHF 3 with CHCl 3 is mainly initiated by the breakage of C Cl. The present work provides a potential resource utilization route for the treatment of CHF 3 and other hydrofluorocarbons (HFCs).
研究领域:
化学
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环境科学
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催化
·
绿色化学
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产品关联
DOI
高影响因子
CHEMISTRY-A EUROPEAN JOURNAL
·
2024
·Vol. 30
·期 68
·e202402516
·
IF 3.9
Chaoyang Yang,Junlei Zhang,Weiping Liu,Yao Cheng,Xueyi Yang,Wanglei Wang
Graphical This study investigated the impact of H 2 /CO 2 partial pressure ratios on CO 2 methanation using Ni/CeO 2 . Results show elevated H 2 /CO 2 ratios enhance CO 2 conversion and CH 4 selectivity, achieving complete methanation at 250 °C and 100 % selectivity at 400 °C. In-situ DRIFTS analysis indicates formate pathway dominance at higher ratios, key for CH 4 production and CO 2 mitigation strategies. On the way to carbon neutrality, directly catalyzing atmospheric CO 2 into high-value chemicals might be an effective approach to mitigate the negative impacts of rising airborne CO 2 concentrations. Here, we pioneer the investigation of the influence of the H 2 /CO 2 partial pressure ratio (PPR) on air-level CO 2 methanation. Using Ni/CeO 2 as a case catalyst, increasing H 2 /CO 2 PPR significantly improves low-temperature CO 2 conversion and high-temperature CH 4 selectivity, i. e., from 10 of H 2 /CO 2 PPR on, CO 2 is completely methanized at 250 °C, and nearly 100 % CH 4 selectivity is achieved at 400 °C. 100-hour stability tests demonstrate the practical application potential of Ni/CeO 2 at 250 °C and 400 °C. In-situ DRIFTS reveal that reinforced formate pathway by increasing H 2 /CO 2 PPR is responsible for the high CH 4 yield. In contrast, even though the CO pathway dominated CO 2 conversion on Ni is enhanced by rising H 2 /CO 2 PPR, but at a high reaction temperature, the promoted CO desorption still leads to lower CH 4 selectivity. This work offers deep insights into the direct air-level CO 2 resourceization, contributing to the achievement of airborne CO 2 reductions.
研究领域:
化学工程
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环境科学
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产品关联
DOI
PubMed
高影响因子
SOIL BIOLOGY & BIOCHEMISTRY
·
2024
·
IF 9.8
Jinzhi Yao,Minghui Xie,Linpeng Yu,Ting Liu,Tim J. Clough,Nicole Wrage-Mönnig,Jiafa Luo,Chunsheng Hu,Tida Ge,Shungui Zhou,Shuping Qin
Iron (Fe) plaque is a concentrated form of microbially available Fe oxide that coats rice plant root surfaces, representing a high density of Fe oxide and which potentially mediates paddy soil CH 4 emissions. Using a combination of methods including Fe plaque induction, isotopic labeling , pure microbial strains, and Fe oxide addition experiments, we investigated the impact of Fe plaque on methane (CH 4 ) emissions from paddy soils and explored the associated mechanisms underlying the influence of Fe plaque on CH 4 emissions. A 13 C–CH 4 isotopic labeling experiment showed that Fe plaque did not significantly affect CH 4 oxidation and associated gene expression, whereas Fe plaque significantly enriched methanogenic archaea and their expression of genes associated with methanogenesis. Pure microbial strain and Fe oxide addition experiments showed that the enhancement of CH 4 production in the presence of Fe plaque was caused by the (semi) conductive minerals within the Fe plaque, specifically, hematite , which promoted the extracellular electron transfer between the methanogenic archaea and their syntrophic bacteria, resulting in enhancement of methanogenesis. Our results imply that the presence of Fe plaque will accelerate CH 4 emissions from paddy soils and suppressing Fe plaque has the potential to mitigate CH 4 emissions.
研究领域:
环境微生物学
·
土壤学
✓ 已验证
DOI
高影响因子
JOURNAL OF RARE EARTHS
·
2019
·
IF 2.846
Dingwen Kang,Jie Yu,Wenhui Ma,Min Zheng,Yunfei He,Pengfei Li
In this study, Cu/Ni-La 0.7 Sr 0.3 Cr 0.5 Mn 0.5 O 3– δ (LSCM) catalysts were synthesized via the citric acid-nitrate process (CNP) and chemical co-precipitation. The catalytic performance of Cu/Ni-LSCM catalysts on dry methane reforming was evaluated in a fixed-bed reactor at 550/650 °C and atmosphere pressure. Cu/Ni loading was investigated as an influencing factor, which led to 5 cases of samples according to the different Cu/Ni mass ratios. The catalysts were characterized by X-ray diffraction (XRD), field emission-scanning electron microscope (FE-SEM), Brunauer-Emmett-Teller (BET) measurement, X-ray photoelectron spectroscopy (XPS), hydrogen-based temperature-programmed reduction (H 2 -TPR) and thermos gravimetric analyzer (TGA). The results show that the methane conversion increases, the resistance against metal sintering increases and the carbon deposition drops after the copper is introduced. This optimum performance can be obtained under Case 3 (Cu:Ni:LSCM = 1:3:6 in mass ratio).
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
WATER RESEARCH
·
2024
·
IF 11.4
Jikang You,Fei Liu,Yongwu Wang,Chongsen Duan,Lu Zhang,Huishan Li,Junjian Wang,Huacheng Xu
Lingering inconsistencies in the global methane (CH 4 ) budget and ambiguity in CH 4 sources and sinks triggered efforts to identify new CH 4 formation pathways in natural ecosystems. Herein, we reported a novel mechanism of light-induced generation of hydroxyl radicals (•OH) that drove the production of CH 4 from aquatic dissolved organic matters (DOMs) under ambient conditions. A total of five DOM samples with different origins were applied to examine their potential in photo-methanification production under aerobic conditions, presenting a wide range of CH 4 production rates from 3.57 × 10 −3 to 5.90 × 10 −2 nmol CH 4 mg-C −1 h −1 . Experiments of •OH generator and scavenger indicated that the contribution of •OH to photo-methanificaiton among different DOM samples reached about 4∼42 %. In addition, Fourier transform infrared spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry showed that the carbohydrate- and lipid-like substances containing nitrogen-bonded methyl groups, methyl ester, acetyl groups, and ketones, were the potential precursors for light-induced CH 4 production. Based on the experimental results and simulated calculations, the contribution of photo-methanification of aquatic DOMs to the diffusive CH 4 flux across the water-air interface in a typical eutrophic shallow lake (e.g., Lake Chaohu) ranged from 0.1 % to 18.3 %. This study provides a new perspective on the pathways of CH 4 formation in aquatic ecosystems and a deeper understanding on the sources and sinks of global CH 4 .
研究领域:
环境科学
·
生态学
✓ 已验证
DOI
PubMed
高影响因子
CHEMOSPHERE
·
2018
·
IF 4.427
Cong Li,Qiufeng Lin,Feilong Dong,Yuanhao Li,Feng Luo,Kejia Zhang
Chlorination is essential to provide safe drinking water . However, this process leads to the formation of disinfection byproducts (DBPs). In this study, tryptophan (Trp) has been selected as a precursor to conduct the chlorine disinfection. Moreover, the factors that affect the formation of trihalomethanes (THMs) and iodinated trihalomethanes (I-THMs) are investigated. The formation pathway of Trp chlorination is proposed based on the intermediate products identified. According to the experimental results, the formation of THMs and I-THMs during Trp chlorination fitted a new first-order kinetic model. The dosage of chlorine, temperature, pH and the ratio of bromide and iodide had major influence on the formation of THMs and I-THMs during chlorination. In addition, the inhibition of luminescent bacteria Vibrio fischeri in the water sample increased during Trp chlorination.
研究领域:
环境科学
·
水处理工程
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF SOILS AND SEDIMENTS
·
2021
·Vol. 22
·期 2
·470-481
·
IF 3.308
Zhang Wantong,Kang Xiaoming,Kang Enze,Audet Joachim,Davidson Thomas A.,Zhang Xiaodong,Yan Liang,Li Yong,Yan Zhongqing,Zhang Kerou,Wang Jinzhi,Hu Zhengyi
Purpose Alpine wetland ecosystems can contribute large amounts of methane (CH 4 ) to the atmosphere; however, their emissions vary with environmental conditions. Microbial activity is known to drive CH 4 emissions, but how environmental conditions determine microbial activity is still uncertain. Here, we seek to quantify the variability of the CH 4 flux, to detect the effects of CH 4 -related microbes on CH 4 emissions, and to study the dependency of these effects on environmental conditions. Materials and methods We measured the CH 4 flux, environmental conditions, and CH 4 -related microbial communities ( mcrA and pmoA gene abundances for methanogens and methanotrophs, respectively) under three hydrological conditions (submerged, soil–water interface, and emerged) from seven sampling sites in the Zoige alpine wetland, China. Results and discussion The CH 4 flux varied greatly from 0 to 41 mg m −2 h −1 in the Zoige alpine wetland. The methanogenic and methanotrophic abundances both showed positive correlations with CH 4 flux, while CH 4 flux increased linearly with the increase of soil water content (SWC) when SWC was above 60%. CH 4 flux and methanogenic and methanotrophic abundances maintained the high levels when soil C:N ratio was in the range of 11–24 and decreased exponentially with the increase of soil DOC:TN ratio in Zoige alpine wetland, which might result from its influence on nutrient supply for microbial decomposition process. Conclusion The results provided new insight into the effects of CH 4 -related microbes on CH 4 emission and its response to different environmental conditions and helped us to comprehend the risks of high CH 4 emissions from alpine wetlands under climatic change and anthropogenic disturbance.
研究领域:
生态学
·
微生物学
·
环境科学
✓ 已验证
DOI
高影响因子
Environmental Science-Water Research & Technology
·
2017
·Vol. 4
·期 2
·218-225
·
IF 2.817
Fang Yang,Zhaoguang Yang,Haipu Li,Fangfang Jia,Ying Yang
Swimming pool disinfection by-products (DBPs) have aroused widespread concern in many countries due to their adverse human health effects. In this study, the concentration levels of several kinds of DBPs including trihalomethanes, haloacetonitriles and trichloronitromethane were determined in 35 outdoor swimming pools in Hunan, China. The main water parameters investigated in this study included free residual chlorine, total organic carbon, pH, urea, UV254, total nitrogen and temperature. The management and operation of pools were comprehensively investigated as well. The results showed that the mean concentrations of trihalomethanes, haloacetonitriles and trichloronitromethane in the swimming pools were 21 ± 14 μg L−1, 2.1 ± 1.4 μg L−1 and 0.91 ± 0.51 μg L−1, respectively. Chloroform was the most predominant DBP species detected, and dichloroacetonitrile was the most predominant nitrogenous DBP (N-DBP) species detected. Free residual chlorine and pH might be critical factors in controlling the occurrence of DBPs. Showering before entering the pool could reduce the organic matter from swimmers, and this practice seemed to be an effective way to reduce the formation of DBPs. It is worth noting that urea, as one of the most predominant organic nitrogen compounds in human sweat and urine, had a high concentration in the investigated swimming pool samples. The cancer risks of DBPs in these outdoor swimming pools were lower than the US EPA guidelines in general, while the harm of DBPs couldn't be overlooked at high concentrations.
研究领域:
环境科学
·
公共卫生
✓ 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）