SCIENCE OF THE TOTAL ENVIRONMENT
·
2023
·
IF 9.8
Chuxuan Zhang,Xun Gong,Jianhui Zeng,Zhengkang Peng,Xiaomin Li,Luqiu Lin,Yang Peng,Shuang Wang
Liquefaction of microalgae in ethanol offers an eco-friendly bio-oil alternative, but solvent recycling is crucial for sustainability due to extra costs. In this work, Chlorella vulgaris was liquefied in supercritical ethanol at 260 °C, and the solvent phase (SP) separated from bio-oil was recovered and reused. Five liquefaction cycles were performed at identical temperature and pressure conditions to investigate the effects on oil production and nitrogen transformation. The findings demonstrated a gradual increase in water content in recycled SP. Ethanol-water co-solvent as the reaction medium promoted the decomposition and re-polymerization of protein in raw material, thus increasing the bio-oil yield (76.84 %) and higher heating value (33.53 MJ/kg) to some extent. Simultaneously, the relative nitrogen content of bio-oil rose from 8.03 % to 8.52 %, predominantly in the form of nitrogen heterocycles. The potential pathway for nitrogen conversion was revealed, which establishes a theoretical basis for the subsequent denitrification of bio-oil.
研究领域:
生物能源
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FUEL
·
2023
·
IF 7.4
Jinchuan Wang,Li Zhang,Jinping Weng,Juntao Wei,Deliang Xu,Bin Li,Shu Zhang,Mortaza Gholizadeh,Electo Silva Lora,Hong Zhang
The retention and transformation of nitrogen in hydrochars prepared from co-hydrothermal carbonization (Co-HTC) of fiberboard (FB) and glucose were mainly investigated in this study. This study showed that more than 90 wt% nitrogen has transferred into aqueous solution at 180–220 °C during the hydrothermal carbonization (HTC) of FB. When the HTC temperatures were higher than 220 °C, some dissolved nitrogen recombined into hydrochars due to the enhancement of nitrogen fixation reactions (Maillard reactions). The addition of glucose could significantly increase nitrogen retention rate in hydrochars, which was due to abundant oxygen-containing intermediates (5-HMF, furfural, etc.) formed in aqueous phase by the hydrothermal decomposition of glucose. Besides, the hydrochars with more microspheres formed on the surface could apparently enhance nitrogen fixation due to the increased contacting area. In Co-HTC, the temperature range of 220–280 °C favored the nitrogen retention in hydrochars. Additionally, nitrogen retention rate increased significantly with increasing residence time and mixture ratio of glucose in a certain extent. While the heterocyclic-N was the main nitrogen functional group in hydrochars and it transformed from pyridinic-N, pyrrolic-N to quaternary-N with higher HTC temperatures and longer residence times, additionally, some amine-N was clearly formed when the nitrogen returned from the aqueous phase into hydrochars.
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
PROCEEDINGS OF THE COMBUSTION INSTITUTE
·
2014
·
IF 3.828
Huan Liu,Qiang Zhang,Hongyun Hu,Peng Liu,Xiaowei Hu,Aijun Li,Hong Yao
Thermal disposal of sewage sludge is likely to cause serious nitrogen related environmental pollution since it contains considerable amounts of nitrogen, the species of which are quite different from those in coal. Considering that lime (CaO) is a widely applied chemical conditioner for sewage sludge dewatering, this study investigated the catalytic role of conditioner CaO in nitrogen transformation during sewage sludge pyrolysis in a drop-tube/fixed-bed furnace at 873 K, 1073 K and 1273 K, respectively. Model compounds were also used to further clarify the mechanisms involved. According to the results, conditioner CaO increased the fraction of more stable protein-N as well as amine-N. The solid phase reactions produced CaC x N y , thus enhancing the nitrogen retention in char. Correspondingly, decreased relative ratio of nitrates-N/nitrites-N and oxygenated organics in sludge conditioning contributed to less NO emission. Meanwhile, conditioner CaO promoted the conversion of HCN to NH 3 , as well as the deamination of proteins, amine, and other N-containing compounds in tar and char, leading to increased NH 3 generation. Subsequently, CaC x , the decomposition product of CaC x N y , captured NH 3 , driving down the final production of NH 3 . In addition, Ca(OH) 2 hindered the transformation of nitrile-N in char to HCN, decreasing HCN generation. CaO reacted with HCN, further reducing its releasing amount. CaC x N y derived from different sources decomposed to produce a very large amount of N 2 . These indicate that reusing conditioner CaO is a promising strategy for reducing the productions of NO x precursors efficiently and increasing the formation of non-polluting N 2 dramatically.
研究领域:
环境科学
·
能源与燃料
✓ 已验证
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2024
·
IF 5.8
Hong Tian,Xuan Huang,Bin Zhao,Huang Zhang,Shan Cheng,Lei Liu
Biomass pyrolysis has the potential to be transformed into valuable chemicals and fuels. Nitrogenous chemicals exert a substantial influence on the quality of bio-oil. Studying the impact of lignin on the transformation of nitrogen-containing elements in biomass during biomass pyrolysis is crucial for achieving efficient and effective utilization of biomass resources. In this study, tube furnace experiments, thermogravimetric infrared experiments (TG-FTIR), and gas chromatography-mass spectrometry (Py-GC/MS) were used to investigate the interactions of typical lignins (vanillin and syringol), nitrogenous components (glutamic acid), and the effect of lignin on the pyrolysis gas release of glutamic acid and the pyrolysis products during the co-pyrolysis process. In addition, the impact of lignin on the effect of pyrrolidone formation from glutamic acid was investigated in this study in conjunction with quantum chemical calculations. The experimental findings demonstrated that the co-pyrolysis of lignin and glutamic acid resulted in a reduction in the pyrolysis temperature. This reduction facilitated the release of HCN, NH 3 , and CO 2 while notably impeding the formation of nitrogen-containing compounds in the oil. The nitrogen concentration in the pyrolysis oil declined from 97 % to a range of 51.06–79.63 %, and the inhibitory impact decreased as the pyrolysis temperature increased. At an elevated pyrolysis temperature of 800 °C, lignin facilitated the decarboxylation process of glutamic acid, resulting in an increased production of pyrrolidone.Simulation results demonstrated that the lowest energy barrier paths were the dehydration condensation process and the Maillard reaction involving glutamic acid and lignin and their pyrolysis intermediates, with a particular competitive connection between the two pathways. The results explained the interaction mechanism between the two pyrolysis products and provided a fundamental theoretical basis for nitrogen conversion in biomass pyrolysis.
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
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
Journal of Cleaner Production
·
2023
·
IF 11.1
Shi Liu,Wen Cao,Fanrui Meng,Mingming Du,Wenwen Wei,Yunan Chen,Hui Jin,Liejin Guo
Supercritical water gasification (SCWG) of biomass waste as a new clean waste conversion technology is increasingly valued worldwide attributable to the unique properties of supercritical water (water: T > 374 °C, P > 22.1 MPa). However, the fate of conventionally contaminated elements such as nitrogen in this process still warrants further research to control potential contamination. In this work, uric acid was used as the model compound of nitrogenous components in chicken manure to investigate the transformation mechanism of nitrogen during the SCWG process. The effects of different temperatures (550–650 °C) and residence times (2–30 min) on the gasification characteristic of uric acid and the behaviour of nitrogen were experimentally explored. The results indicated that the higher temperatures and longer residence time significantly facilitated the uric acid gasification and nitrogen transformation. The maximum nitrogen conversion efficiency was 84.83%, and the maximum yield of NH 3 , H 2 , and CO 2 reached 20.20 mol/kg, 23.78 mol/kg, and 20.10 mol/kg at 650 °C and 30 min, respectively. Subsequently, the reaction pathways of nitrogen in uric acid were proposed in detail according to the product analysis. Finally, a kinetic model was developed to describe the SCWG process, especially the reaction kinetic of nitrogenous products. The results revealed that the hydrolysis reactions of uric acid led to a rapid increase in NH 3 yield in the initial stage of the SCWG process. As the process continued, the increase in NH 3 was mainly due to the deamidation reaction of small-molecule nitrogenous intermediates. Notably, NO x , NO 2 − , and NO 3 − were not detected in products, validating the inhibitory effects of the reducing environment of supercritical water on the generation of nitrogen oxides.
研究领域:
环境科学
·
能源工程
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE ENERGY INSTITUTE
·
2024
·
IF 5.6
Zhangjun Huang,Ziqi Tang,Hong Tian,Linli Shang,Xuan Huang,Lei Liu,Yanni Xuan
s: Nitrogen-containing compounds become a bottleneck in the conversion of biomass pyrolysis oil into high-value chemicals and fuels, and they are easily oxidized to nitrogen oxides in the subsequent utilization process, causing serious pollution to the environment. Lignin, a biomass component, has an important influence on nitrogen migration during biomass pyrolysis. In this study, we investigated the interaction of lignin model compounds (vanillin and Syringol) with nitrogen-containing components (phenylalanine) during lignin/amino acid co-pyrolysis using tube furnace experiments, thermogravimetric infrared (TG-FTIR) experiments, and gas chromatography-mass spectrometry (Py-GC/MS), as well as the effect of lignin on the pyrolysis gas release and pyrolysis products of phenylalanine, in conjunction with quantum chemical calculation The effect of lignin on the pyrolysis of phenylalanine to styrene was explored. The experimental results showed that during the co-pyrolysis process, lignin modulators (vanillin and Syringol) dramatically reduced the temperature of the first stage of phenylalanine pyrolysis; promoted the pyrolysis oil generation and inhibited the pyrolysis gas generation; vanillin and Syringol promoted the fracture of oxygen-containing and nitrogen-containing functional groups of the side chain of phenylalanine, which resulted in a significant increase in the yields of aromatic hydrocarbons in the pyrolysis oils, with an increase of 32.07 % and 23.41 %, respectively. The simulation results showed that the hydrogen radicals generated by lignin modulators would promote the carbon ring breakage, decarboxylation and intermolecular ring-forming reaction of phenylalanine side chain to generate 1,2-diphenylethene, styrene and NH 3 , and promote the nitrogen-containing carbon chain to undergo intramolecular hydrogen transfer to form HCN, which was converted into styrene pathway showing strong competitiveness.
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
Crop & Pasture Science
·
2023
·Vol. 74
·期 12
·1318-1333
·
IF 1.9
Jackson Nkoh Nkoh,Peng Guan,Ren-yong Shi,Ru-hai Wang,Jiu-yu Li,Ren-kou Xu
Context Carbon (C) and nitrogen (N) transformation processes in soils play an important role in the fluctuation of soil pH. Incorporation of chitosan and crop straws, byproducts from fishery and agriculture, into acidic soils can increase soil pH through decarboxylation, decomposition, N immobilisation and ammonification.Aims The study was designed to evaluate the transformation of organic N and C from chitosan and/or crop straws and their effects on soil physicochemical properties.Methods Chitosan, rice straw and maize straw were incubated with two acidic Ultisols from Langxi (Soil 1) and Yingtan (Soil 2) differing in initial pH. Six treatments were prepared in triplicate: control (no amendment), 4% chitosan, 4% rice straw, 4% maize straw, 2% chitosan+2% rice straw, and 2% chitosan+2% maize straw. Soil pH, N transformation and CO2 evolution were estimated at different time intervals.Key results After 40days of incubation, control soil pH decreased by 0.35 and 0.32 units for Soils 1 and 2, respectively. Rice straw, maize straw, chitosan, rice straw–chitosan and maize straw–chitosan significantly increased soil pH by 0.51, 0.17, 2.27, 1.78 and 2.02 units for Soil 1, and 0.71, 0.16, 0.67, 0.49 and 0.68 units for Soil 2 (P<0.01). The respective treatments decreased exchangeable acidity by 62%, 51%, 95%, 95% and 95% for Soil 1 and 75%, 69%, 88%, 88% and 87% for Soil 2. In treatments containing chitosan, the pH increase resulted from ammonification of organic N and mineralisation of organic C, with the effect higher in Soil 1 than Soil 2.Conclusions Amending acidic soils with chitosan and crop residues can effectively increase soil pH and slow soil acidification rate.Implications This study provides useful information for amelioration of acidic soils.
研究领域:
土壤学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
·
2024
·
IF 6.9
Shuai Guo,Yu Wang,Jianwen Yi,Deng Zhao,Deyong Che,Hongpeng Liu,Baizhong Sun
Co-pyrolysis of sludge and waste plastics is a long-term strategic approach for producing valuable fuels. However, sludge is characterized by a high protein content, which serves as a significant source of nitrogenous components in bio-oil. To improve the quality of pyrolysis products, the present study investigated the effect of low-density polyethylene (LDPE) on nitrogen transformation during the pyrolysis of sludge protein (SP). The study findings indicated that LDPE addition reduced the amount of solid residue owing to the interaction between SP and H radicals generated by LDPE pyrolysis. The thermal weight loss difference consistently remained below 0 when the SP-to-LDPE mixing ratio was 7:3, indicating that LDPE promotes the pyrolysis of SP. For the analysis of nitrogen-containing products during pyrolysis, LDPE addition significantly reduced the levels of nitrogen-containing compounds in the bio-oils of glutamate (Glu), histidine (His), and tyrosine (Tyr). Specifically, at 600°C, Glu, His, and Tyr in the bio-oils decreased by 31.4%, 33.3%, and 34.38%, respectively. No significant changes were observed in the nitrogen content within the pyrolysis char of Glu and His. However, all three amino acids exhibited a significant increase in the formation of NO x precursors due to the attack on the nitrogen positions of the heterocyclic nitrogen species by the H radicals generated by LDPE. This study contributes to research on the impact of LDPE on nitrogen migration and conversion during the pyrolysis of SP, laying the foundation for subsequent studies on pollutant removal reactions.
研究领域:
环境科学
·
能源与燃料
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Yi Qu,Xiao Song,Xi Chen,Xiang Fan,Guan Zhang
Charge transfer efficiency of semiconductor photoanode in photoelectrochemical (PEC) system is one of crucial factor determining the overall PEC performance. Previously, we have developed a MoS 2 -based PEC system that is able to specifically convert ammonia nitrogen in aqueous solution into gaseous nitrogen (e.g. N 2 ) utilizing oxysulfur radicals. Herein, in order to solve the slow charge transfer issue of reported MoS 2 -based PEC oxidation system, we further improve the PEC conversion efficiency by tuning composition of MoS 2 /WS 2 nanosheets heterojunction photoanode. The hybrid MoS 2 /WS 2 (1:1) electrode displays the highest PEC performance and ammonia conversion efficiency compared to the individual MoS 2 or WS 2 constituent under visible light irradiation, which can be mainly ascribed to the reduced electrode resistance and improved charge transfer efficiency according to the physiochemical, electrochemical and spectroscopic analysis. The results prove that both interfacial and interior charge carrier transfer processes of photoanode are crucial and tailorable in order to efficiently generate reactive radical species for ammonia conversion.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Mian Hu,Xiaotong Huang,Letao Sun,Weicheng Zheng,I-Ming Chou,Libo Wu,Jinling Wan,Zhiyan Pan,Junliang Wang
Catalytic oxidation of o -chloroaniline ( o- ClA) in hot compressed water (HCW) was investigated in a fused quartz tube reactor (FQTR) to determine the effects of catalyst, temperature, oxygen stoichiometric ratio (OSR) and reaction time on o- ClA mineralization, total nitrogen (TN) removal rate and nitrogen-containing products distribution. The results showed that o -ClA can be effectively degraded in HCW. With the increased of OSR, retention time and temperature or added of Mn 2 O 3 as catalyst, the mineralization rate of o -ClA and the removal rate of TN increased. Ammonia-N was the main nitrogen-containing intermediate product of o -ClA degradation, however, when the oxidant was excessive, ammonia-N was oxidized to form nitrate-N. Althought the catalytic effect of Mn 2 O 3 on the mineralization of o -ClA was not outstanding, it promoted the removal of ammonia-N from the benzene ring, improved the degradtion of ammonia-N, and inhibited the production of nitrate-N. GC–MS analyzed results indicated that o -chlorophenol was the main degradation intermediate product of o -ClA in HCWO process. Meanwhile, the potential degradation pathway of o -ClA was proposed. This work thus provides basic knowledge about o -ClA catalytic oxidation removal in HCW process.
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
WATER RESEARCH
·
2022
·
IF 13.4
Xiangyu Yang,Lu Zhang,Yi Chen,Qiang He,Tao Liu,Guoqing Zhang,Ling Yuan,Haoran Peng,Hui Wang,Feng Ju
Micro/nano-sized plastics (MPs/NPs) existing in wastewater system are the potential threats to nitrogen (N) biotransformation. Constructed wetlands (CWs) as wastewater treatment systems are considered the important barriers preventing MPs/NPs from entering the open water. However, little is known about how the accumulation of MPs/NPs affects microbial N transformation, dynamics, assembly, and metabolism of wetland microbiota. Herein, we constructed 12 wetland systems to address the above knowledge gaps over 300-day exposure to different sizes (3 mm - 60 nm) and concentrations (10 - 1000 μg/L) of MPs/NPs. The results showed that MPs/NPs accumulation caused decrease in NH 4 + -N removal (by 7.6% - 71.2%) and microbial diversity and intriguingly altered microbiota composition (especially in the high-concentration groups) without damage on the high removal efficiency of NO 3 − -N and NO 2 − -N (66.2% - 99.8%) in all except for the nano-sized plastic-exposed wetlands. Moreover, MPs/NPs exposure induced shift in the strengths of non-random species aggregation and segregation patterns co-differentiated by the size and concentration of MPs/NPs, and MPs/NPs accumulation created size-differentiated alternative niches for nitrogen-transforming bacteria, e.g., canonical nitrifiers ( Nitrospira and Nitrosomonas ) and denitrifiers ( Thauera, Comamonas , and Aquabacterium ), which were enriched in MPs groups where denitrifying enzyme-coding genes were also enriched, suggesting potential positive impact of larger plastics on denitrification. Our study highlights MPs/NPs-induced divergence in microbiota dynamics and nitrogen transformation in CWs, and provides important insights into how microbiota structurally and functionally respond to long-term MPs/NPs disturbance.
研究领域:
环境科学
·
微生物学
✓ 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）