INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2023
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IF 4.2
Erhu Li,Xuliang Lin,Shirong Sun,Xueqing Qiu
The highly selective conversion of technical lignin to low-oxygen-content compounds is still challenging due to the presence of methoxy and ether bonds in natural lignin. Herein, tunable ternary deep eutectic solvents (DESs) containing choline chloride, oxalic acid, and another bifunctional reagent with a hydrogen-bond donor and nucleophilic function were used for the β-aryl ether bond cleavage or Cα-etherification of lignin followed by pyrolysis to improve the yield of methoxy-free lignin monomers. The relationship between the lignin structure and pyrolysis behavior was investigated by 2D-NMR, FTIR, GPC, XPS, TGA, TG-FTIR, EPR, etc. The DES pretreatment changed the pathway of lignin pyrolysis toward a higher yield of bio-oil and methoxy-free products. Compared with technical lignin, the yield of phenolic products after Cα-etherification with ethanol and ethylene glycol as nucleophilic reagents increased from 0.73 × 1011 to 4.10 × 1011 and 5.56 × 1011 area/mg, respectively. Besides, the introduction of ethanol and ethylene glycol is more conducive to the demethoxylation of pyrolysis products and the formation of methoxy-free phenols during pyrolysis. This work realizes the conversion of lignin to high-value phenolic products with low-oxygen-content compounds without adding catalysts by a pyrolysis strategy.
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Frontiers in Chemistry
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2022
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IF 5.545
Qin Xiaoyun,Fu Cuicui,Zhang Jin,Shao Wenlong,Qin Xiaomei,Gui Yanghai,Wang Lan,Guo Huishi,Chen Fenghua,Jiang Liying,Wu Gang,Bikker Floris J.,Luo Dan
The fluorescent carbon dots (CDs) have found their extensive applications in sensing, bioimaging, and photoelectronic devices. In general terms, the synthesis of CDs is straight-forward, though their subsequent purification can be laborious. Therefore, there is a need for easier ways to generate solid CDs with a high conversion yield. Herein, we used collagen waste as a carbon source in producing solid CDs through a calcination procedure without additional chemical decomposition treatment of the raw material. Considering a mass of acid has destroyed the original protein macromolecules into the assembled structure with amino acids and peptide chains in the commercial extraction procedure of collagen product. The residual tissues were assembled with weak intermolecular interactions, which would easily undergo dehydration, polymerization, and carbonization during the heat treatment to produce solid CDs directly. The calcination parameters were surveyed to give the highest conversion yield at 78%, which occurred at 300°C for 2 h. N and S atomic doping CDs (N-CDs and S-CDs) were synthesized at a similar process except for immersion of the collagen waste in sulfuric acid or nitric acid in advance. Further experiments suggested the prepared CDs can serve as an excellent sensor platform for Fe3+ in an acid medium with high anti-interference. The cytotoxicity assays confirmed the biosafety and biocompatibility of the CDs, suggesting potential applications in bioimaging. This work provides a new avenue for preparing solid CDs with high conversion yield.
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JOURNAL OF ENVIRONMENTAL MANAGEMENT
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2022
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IF 8.91
Jiaxing Song,Jun Wang,Yuhan Pan,Xudong Du,Jingyuan Sima,Chenxi Zhu,Fangfang Lou,Qunxing Huang
The increasing demand for plastics has resulted in significant plastic waste accumulation and environmental pollution . Catalytic pyrolysis is an attractive treatment method to mitigate the plastic waste management problems and recover high-value oil products. In our study, waste polyethylene (PE) was pyrolyzed to produce benzene, toluene, ethylbenzene and xylene (BTEX)-enriched oil a using dielectric barrier discharge plasma catalytic pyrolysis reactor. Ga-modified Hydro-Zeolite Socony Mobile-Five (HZSM-5) was used as a pyrolysis catalyst. The effects of the PE to Ga/HZSM-5 ratio and discharge power on BTEX enhancement and carbon deposition are discussed. The greatest BTEX selectivity (77.04%) and relatively low coke yield (1.37%) were achieved when the PE/(Ga/HZSM-5) ratio was 2:1 with a non-thermal plasma (NTP) discharge power of 20 W. The regeneration effects of conventional thermal oxidation and NTP on the zeolite catalyst were compared. NTP regeneration at a low temperature (150 °C) achieved the same coke removal rate as that of thermal regeneration at high temperatures (500 °C). Ga/HZSM-5 subjected to NTP regeneration showed higher activity for BTEX formation (BTEX selectivity was 42.10%) as compared to that shown by Ga/HZSM-5 subjected to thermal regeneration (BTEX selectivity was 40.59%). The NTP synergistic catalytic pyrolysis of plastics over Ga/HZSM-5 was found to be a promising strategy for mitigating the plastic waste management problems and upgrading the quality of oil products.
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Frontiers in Energy Research
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2022
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IF 3.858
Wang Hongfei,Zhao Xiqiang,Yang Xinfei,Sun Shuang,Wang Wenlong,Mao Yanpeng,Song Zhanlong
In this paper, two types of adsorption materials SA-C-Fe and SA-C-Fe(C) were prepared using bagasse biochar produced by one-step microwave pyrolysis and activation for Cr(VI) removal of wastewater. The adsorption materials were characterized, and Cr(VI) adsorption performance, kinetics and thermodynamics on adsorption materials were studied. Results show that microwave pyrolysis/activation contributes to developed pore structure and abundant active functional groups, resulting in high Cr(VI) adsorption capacities. The optimal preparation conditions for biochar is: microwave power 500 W, ZnCl2/bagasse ratio 2.5:1 and pyrolysis/activation time 15 min, and the specific surface area of biochar is 1,787.64 m2/g. The Cr(VI) adsorption of the two materials is more in line with the pseudo-second-order kinetic model, and the adsorption process is dominated by chemical adsorption. The static removal experiment of Cr(VI) using SA-C-Fe and SA-C-Fe(C) has the best removal effect at pH = 2, and the whole adsorption process is more in line with the Langmuir-Freundlich isotherm model. Calculated by the pseudo-two-order kinetic model and the Langmuir-Freundlich isothermal model, the maximum adsorption rate for Cr(VI) of SA-C-Fe and SA-C-Fe(C) are 211.87 mg/g and 388.92 mg/g, respectively. The removal process is mainly dominated by three mechanisms: electrostatic adsorption, ion exchange and redox reactions. The improvement of Cr(VI) adsorption capacity is attributed to more developed pore structure. The results offer beneficial reference for the application of low-cost carbon-based adsorption materials for pollutants separation, and effectively realize the utilization of bagasse pyrolysis by-products.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2022
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IF 6.371
Xiaotong Zhu,Yuanyuan Zhang,Shengxiao Zhang,Shuangshuang Yang,Qiang Xu
In this study, biomass carbon supported with iron and cobalt bimetal (FeCo/BC) was synthesized by a one-pot calcination method to activate peroxymonosulfate (PMS) and peroxydisulfate (PDS) for bisphenol A (BPA) degradation. Characterization with X-ray diffraction, X-ray photoelectron spectroscopy and high resolution transmission electron microscopy showed that Fe 0 , Fe 3 O 4 , Co 0 and CoO nanocrystals were included in FeCo/BC materials. The degradation results showed Fe 0.6 Co 0.4 /BC had excellent catalytic activation performance for PMS or PDS. The Fe 0.6 Co 0.4 /BC (0.0050 g) combined with 0.25 g·L −1 of PMS could completely degrade 20 mg·L −1 BPA within 8 min, and the same amount of BPA could be removed with 0.020 g Fe 0.6 Co 0.4 /BC in the presence of 0.25 g·L −1 PDS within 20 min. The corresponding total organic carbon removal rates reached 83.49% and 77.5% respectively after 2 h. The Fe 0.6 Co 0.4 /BC also had good adaptability to solution pH and practical water body. After five cycles, the degradation rates of BPA in the two systems were all over 90%, and excellent magnetism was beneficial to the reuse of catalysts. Electron paramagnetic resonance and free radical quenching tests indicated that SO 4 •- , •OH, and 1 O 2 were the main active species involved in the BPA degradation. This work not only provided a promising catalyst for the degradation of organic pollutants, but also elucidated the synergistic effect between Fe-Co bimetal alloys during PMS and PDS activation, which would facilitate the design, synthesis, and application of catalytic materials with high efficiency.
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FUEL
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2022
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IF 8.035
Qi Zhao,Xianfeng Chen,Yi Li,Huaming Dai
To explore the suppression mechanisms of ammonium polyphosphate (APP) on methane/coal dust explosion flame, the experiment tests of methane/coal dust explosion flame propagation under different mass fraction of APP were conducted in a vertical pipe. Using Simultaneous Thermal Analysis and Py-GC/MS to analyze the effects of APP on the thermal decomposition process and thermal pyrolysis products of coal dust. The chemical characterization of explosion residues was carried out by confocal Raman and Fourier transform infrared spectroscopy (FTIR). Based on the apparent suppression ways of APP such as absorption of heat, reduction concentration of combustibles and adsorbent of free radicals, APP also limited the thermal decomposition process of coal dust and leaded to the reduction or even disappearance of some organic matters at coal dust pyrolysis. Noticeably, the investigation of explosion residues found that the carbonization effect of APP pyrolysis products and the activity reduction of functional groups (–CH 3 /–CH 2 and –OH) which contribute to ignition of coal dust, these coupling effects made it difficult for coal dust to ignite, and thus the methane/coal dust compound explosion were suppressed significantly.
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ENERGY
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2022
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IF 8.857
Haifeng Jiang,Haipeng Liu,Jiaxin Dong,Jiaxing Song,Sunhua Deng,Jie Chen,Yu Zhang,Wenpeng Hong
Using cellulose to produce high-quality oxygenated fuels or chemicals is becoming an important way to replace chemical synthesis technology. In this work, the Ce–Co–Na ternary composite metal catalyst is synthesized and used for catalytic cracking of cellulose to prepare the ketone-rich bio-oil production. To construct an environment-friendly process, CO 2 is used as a pyrolysis reaction atmosphere to improve the enrichment of ketones. Strong synergistic effects among metal components effectively promote the thermal-cracking of cellulose to produce primary products (anhydrosugars), and further convert to oxygenates due to the excellent oxygen transferability of the catalyst. The introduction of CO 2 enhances the selectivity of ketones in the liquid product, especially 2,3-dimethyl-2-cyclopenten-1-one. The highest content of ketones in the liquid is 22.73%, which is about four times higher than that of the blank sample. In addition, the generation of CO in the syngas is promoted. This study provides an alternative way for the pyrolysis of biomass to prepare ketone platform compounds and syngas production .
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JOURNAL OF ALLOYS AND COMPOUNDS
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2021
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IF 5.316
Cheng Cheng,Jian Wang,Zhihao Zhao,Changchun Chen,Sheng Cui,Yifeng Wang,Lin Pan,Yaru Ni,Chunhua Lu
Semiconductor catalyst with high photocatalytic activity can be exploited via heterojunction. In this study, a new S-scheme SrTiO 3 /porous ZnO composite was rationally devised, successfully prepared by utilizing a two-step pyrolysis of SrTiO 3 /ZIF-8, and analyzed by various characterization technologies including XRD, SEM, TEM, BET, XPS, PL, UV–vis DRS, and photoelectrochemical and DFT theoretical calculations. A porous structure, tight contact, and a heterojunction formed between SrTiO 3 and porous ZnO (ZnOT) can be observed by SEM and TEM images. BET testing indicates that the SrTiO 3 /porous ZnO composite (S3ZT) shows the highest specific surface area (30.37 m 2 /g). The band gap values (E g ) of SrTiO 3 and ZnOT are around 3.17 and 2.95 eV, which agree with those obtained from DFT calculations. Compared to other samples, the SrTiO 3 /porous ZnO composite (S3ZT) shows higher light absorption and lower transfer resistance as demonstrated by UV–vis DRS and EIS results. S3ZT presents a superior photocatalytic efficiency of 48.8% in degrading 5 mg/L methyl orange (MO) irradiated by 1 h UV–vis light, which are 7- and 1.5-fold higher than pristine SrTiO 3 and ZnOT, respectively. Moreover, based on Mott-Schottky theory, active species trapping experiments, XPS determination, and DFT calculations (energy band gap and work function), it was shown to be reasonable to utilize the S-scheme charge migration process for an explanation regarding the better photocatalytic activity of SrTiO 3 /porous ZnO composite. Overall, this work will provide an effective protocol for devising and preparing semiconductor photocatalysts with S-scheme heterojunction by utilizing the superior characteristics of MOFs.
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SCIENCE OF THE TOTAL ENVIRONMENT
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2021
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IF 7.963
Yu Wan,Yan Hu,Wenjun Zhou
To scrutinize the crucial role of carbon configuration and nitrogen speciation in peroxymonsulfate (PMS) activation, nitrogen-doped biochars (NBCs) were prepared at different pyrolysis temperatures (700, 800 and 900 °C) and named NBC700, NBC800 and NBC900, respectively. Nitrogen doping introduced many nitrogen-containing groups into NBCs and the carbon configuration and nitrogen speciation of NBCs were regularly changed by the pyrolysis temperature. Compared to the phenol (PN) removal in the pristine biochar (BC)/PMS system that mainly depended on adsorption, NBCs showed excellent PMS activation activity for efficient PN degradation and the PMS activation activity was highly dependent on the carbon configuration and nitrogen speciation of NBCs. Furthermore, the PMS activation pathways of NBCs were unveiled to convert 1 O 2 to electron transfer with increasing pyrolysis temperature, which was ascribed to the variation of active sites on NBCs caused by the regular changes in carbon configuration and nitrogen speciation. Pyridinic N and oxygen groups (C O, C O and O-C=O) were proposed as potential active sites on NBC700 and NBC800 for 1 O 2 generation via PMS activation. Differently, the highly sp 2 -hybridized carbon skeleton and graphitic N of NBC900 played an important role in the electron transfer pathway by acting as a carbon bridge to accelerate electron transfer from PN to PMS. This study provides new insight into the effects of carbon configuration and nitrogen speciation on PMS activation mechanism of NBCs and identifies opportunities for the subsequent catalyst design in a specific degradation pathway.
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JOURNAL OF THE ENERGY INSTITUTE
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2023
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IF 5.7
Shanjian Liu,Wenjing Zhao,Zhisen He,Mengqian Yin,Jingang Yao,Weiming Yi
Different volume ratios of carbon dioxide and nitrogen were mixed into the nitrogen-rich pyrolysis of cellulose , resulting in the production of nitrogen-doped biochar and nitrogen-containing bio-oil. When the urea mixture ratio was greater than 50%, the added CO 2 promoted the production of nitrogen-containing bio-oil, reaching a maximum of 26.03% ( M = 50%) at 10 vol% CO 2 + 90 vol% N 2 . Pyridine , pyrrole , and amines were the main nitrogen-containing compounds produced when using atmospheres of pure nitrogen and carbon dioxide. Upon increasing the volume ratio of CO 2 , the nitrile content increased significantly, becoming one of the main nitrogen-containing compounds. In addition, due to chemical stability, the thermal conversion of CO 2 demands a significant input of energy, so the required activation energy also increased. Adding CO 2 to simulate high-temperature anoxic flue gas is a promising method for biomass pyrolysis to obtain nitrogen containing chemicals with high added value and high nitrogen doped Biochar.
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JOURNAL OF HAZARDOUS MATERIALS
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2023
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IF 13.6
Kaixin Li,Chenghan Cai,Wenjie Zhou,Yiqian Wang,Tan Giin Yu Amy,Zhipeng Sun,Yonggang Min
The transformation of waste plastics to fuel products is an appealing strategy to address plastic-associated environmental and energy issues. In this study, a tandem pyrolysis–catalytic upgrading approach, using a series of mono-/bitransition-metal-modified Si-pillared vermiculite catalysts, was adopted to transform disposable grocery bags (i.e., a polyethylene-based material) to kerosene-range fuels. The results revealed that the silicon pillars contributed to the catalyst’s excellent thermal stability to withstand temperatures of up to 1000 °C, while the transition-metallic species (e.g., Co/Ni/Fe) contributed to the fine-tuning of the catalyst’s acidity and porosity. Specifically, Co–Fe/Si-pillared vermiculite (SPV) (5:5) produced the highest yield of oil products (75.7 wt%), with alkane and aromatic selectivities of 57.5% and 27.8%, respectively, resembling the composition of kerosene. The catalyst’s high selectivities for the targeted products were attributed to the controllable acidity and porosity, enabling a balance to be achieved between these two properties. Pathways were proposed for the tandem pyrolysis in the presence of Co–Fe/SPV. The vermiculite-based catalysts showed satisfactory reusability following regeneration. Beyond polyethylene-based plastics, these catalysts are also applicable to the pyrolysis of other plastic feedstocks. Because vermiculite is a low-cost material, the developed catalyst has good commercialization potential for a wide spectrum of waste-to-energy conversions.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2022
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IF 9.136
Zhongmin Feng,Xuan Zhai,Ting Sun
Pharmaceuticals and personal care products (PPCPs) have recently become a cause of growing concern due to their persistence in the human body and in the ecosystem. Therefore, it is important to develop a material with high adsorption capacity in order to effectively remove them. In the present study, magnetic porous biochar (MAGB) obtained from a biomass garlic skin was prepared through a one-step magnetization pyrolysis and was examined via SEM, XRD, Raman, XPS, TG, VSM, and N 2 adsorption–desorption analysis. MAGB presents many advantages, such as a high specific surface area, good ferromagnetic properties, and oxygen-rich functional groups. The capacities of MAGB to adsorb paraben, metronidazole, and oxytetracycline have been reported at 415, 287, and 822 mg g −1 , respectively, which are more effective than the values recorded for most other adsorbents. Furthermore, MAGB presents a good adsorption capacity after three cycles. The removal mechanisms of PPCPs onto MAGB are attributable to pore adsorption, hydrogen bonding, π-π stacking action, and electrostatic effects. This study demonstrates the applicability of MAGB as a reliable adsorbent, which holds a great potential for the removal of PPCPs from aquatic environments.
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