RSC Advances
·
2019
·Vol. 9
·期 68
·39914-39923
·
IF 3.049
Cheng Qian,Yefei Wang,Zhen Yang,Zhengtian Qu,Mingchen Ding,Wuhua Chen,Zhenpei He
The in situ N2 generation technique is a promising method for enhancing oil recovery (EOR) and blockage removal. Conventionally, N2 is generated through the redox reactions of sodium nitrite (NaNO2) and ammonium chloride (NH4Cl). The effect of several parameters on N2 production was studied in this work. The reaction kinetics between NaNO2 and NH4Cl were developed. The results revealed that the optimal molar ratio was 1 : 1 for the reactants and a higher concentration of reactants, H+ and higher temperature would lead to an increase in the gas production volume and a better gas-generating efficiency. The kinetic equation of the N2 generation reaction was defined as dc/dt = −7.103 × 107 cH+1.3291c02.0949e(−51.28 kJ mol−1)/RT. Methyl formate, ethyl formate, ammonium persulphate as well as paraformaldehyde were selected as authigenic acids by measuring their pH values and their effect on the rate of gas-generation, and the gas production volume was studied. An energy enhancement experiment was conducted to examine the influence of reactant concentration, initial pressure and different authigenic acids on energy enhancement and gas-generating efficiency. The results showed that the increase in reactant concentration can improve the energy enhancement while neither the reactant concentration nor the initial pressure could hardly influence the gas-generating efficiency. The presence of authigenic acids can considerably enhance both the gas production volume and the gas-generating efficiency of the system. The ammonium persulphate assisted N2 generation system is considered to be suitable for field applications.
研究领域:
石油工程
·
化学工程
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2021
·
IF 19.503
Jie Sun,Weiqi Gao,Honghan Fei,Guohua Zhao
Selective electrocatalytic conversion of NO 3 – to N 2 is an environmental-friendly strategy to close the anthropogenic nitrogen-based cycle. This work reported a metal-organic framework-derived electrocatalyst with earth-abundant bimetallic sites, showing quantitative (~97.9% conversion) and selective (~99.3%) nitrate-to-N 2 transformation. More importantly, both post-catalysis concentrations of NO 3 – and NO 2 – meet the drinking water limit requirements, set by World Health Organization. The reaction intermediates and mechanistic pathways in electrocatalytic reduction of NO 3 – to N 2 are elucidated by a variety of in-situ experimental studies and DFT calculations. The enhanced and selective electrocatalytic performances are ascribed to the relay catalytic effects of the neighboring Fe-Ni catalytic sites residing in the porous carbon electrocatalysts, which are structurally determined by X-ray absorption spectroscopy (XAS) as well as calculated structural model, with Fe sites decreasing the reaction barrier for NO 3 – conversion and Ni centers facilitating the adsorption and activation of reaction intermediates (NO 2 – , NO* and N 2 O*).
研究领域:
环境科学
·
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Water Process Engineering
·
2021
·
IF 5.485
Jialin Chen,Ruina Zhang,Dong Chen,Jianyong Liu,Shanping Chen
The generation process for the highly reductive carbon dioxide radical ( CO 2 − ) in the Fe(III)-oxalate system is enhanced under UV irradiation and used in nitrate (NO 3 − ) reduction with improved product selectivity to nitrogen (N 2 ). The combination of Fe(III) and residual oxalate forms Fe(III)-oxalate complexes again for an Fe(II)/Fe(III) species cycle and achieves generation of CO 2 − radical continually. The electron paramagnetic resonance (EPR) spectrum demonstrates the existence of CO 2 − radicals in this process. Some of the important control factors, such as initial concentrations of ferric ions (Fe(III)) (0.5, 1, 2, and 3 mM), NO 3 − (14, 21, and 42 mg N/L), oxalate (3, 7, and 10 mM), and pH values (2, 3, 4, 5, and 6), are systematically assessed for NO 3 − reduction efficiency and N-species selectivity. Among all the control factors mentioned, pH is a key parameter with an important role in the NO 3 − reduction process. Excellent NO 3 − reduction efficiency (∼90 %) was achieved at pH 3 in the presence of 1 mM Fe(III) and 10 mM oxalate under UV irradiation for 120 min. High Fe(III) and oxalate concentrations promote NO 3 − removal. In addition, there was an increase in the NO 3 − removal amount with a greater initial NO 3 − concentration. About 60 % of NO 3 − can be selectively reduced to N 2 with low selectivity to NO 2 − (∼3.4 % of total N) and NH 4 + (∼15.7 % of total N). In general, the UV/Fe(III)-oxalate system provided an alternative way to improve NO 3 − removal performance and selectivity to form N 2 in water and wastewater remediation processes.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2025
·
IF 11.3
Wenjia Huang,Jiabai Cai,Jieyi Gong,Huan Li
Ammonia removal is an essential part of wastewater treatment, and complex biological processes are currently the mainstream, converting ammonia to N 2 with a large footprint and lengthy period. High-temperature (150°C or higher) and high-pressure catalytic oxidation were applied to ammonia conversion, which suffered high investment and operational costs. This study developed a low-temperature catalytic air oxidation process with a fabricated nanoscale Ru/Al catalyst. Through continuous reaction with pH adjustment, it achieved an ammonia conversion rate of 92.0 % at 90°C, with 72.8 % converted to N 2 . During the treatment, ammonia was converted to the key intermediate product N 2 H 2 , accompanied by a small amount of N 2 H 4 , and they were eventually turned into N 2 . In contrast, at 150°C, ammonia was converted to NHO and then to N 2 , and the selectivity was only 43.9 % (most became nitrate). Ammonia form was the critical factor influencing activity energy and conversion efficiency, and maintaining ammonia molecules by pH adjustment could reduce the energy barrier. The formation of the proposed intermediates, N 2 H 2 and N 2 H 4 , was corroborated by FTIR, Raman spectroscopy, and DFT calculations, which confirmed their role in the low-temperature pathway. These findings revealed a new pathway from ammonia to N 2 and provided a unique technical option to clean ammonia-containing wastewater.
研究领域:
环境工程
·
催化化学
·
水污染控制
·
环境材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2023
·
IF 4.2
Zhichao Shen,Yanbin Qi,Wangxin Ge,Hongliang Jiang,Chunzhong Li
Urea electrooxidation reaction (UOR) plays an important role in environmental protection and energy regeneration. The extensively studied nickel-based catalysts exhibit good activity for UOR, but urea is more prone to be overelectrooxidized to another pollutant NOx– (x = 2, 3). Herein, the Cu/Ni-B interface catalyst is presented. The introduction of Cu significantly enhances the Faradaic efficiency of N2 (nearly 70% at 1.70 V versus RHE). Electrochemical tests and in situ Raman spectroscopy results show that the introduction of Cu significantly affects the density of OH* species on the catalyst in the UOR process. It is proposed that with a moderate decrease in OH* density, the catalyst can provide enough sites for urea molecules to allow simultaneous adsorption of the two N atoms, facilitating the process of N-N coupling to form N2. This work is also instructive for the design of electrocatalysts for other nucleophile electrooxidation reactions.
研究领域:
电化学
·
催化
·
环境科学
·
能源转换
✓ 已验证
产品关联
DOI
高影响因子
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