COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2019
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IF 3.131
Nan Zhou,Yifan Wang,Liyang Huang,Jingang Yu,Huanli Chen,Jiajie Tang,Fengjuan Xu,Xiangyang Lu,Mei-e Zhong,Zhi Zhou
Surface modification of biochar is significant to obtain more functionalized material for contaminants immobilization. In situ modification, modifying the biochar while the conversion process, was applied by a novel wet pyrolysis system. By using phosphoric acid as working medium, liquid/air interface was created to introduce low content of oxygen, under the control of appropriately settled reaction temperature. Followed with the addition of sodium carbonate to neutralize the system and increase mineral species, effective biochar adsorbent attached with large quantity of acidic oxygenic and phosphoric groups, and carbonate anions was finally produced. The biochar showed excellent decontamination performance of lead with a high adsorption capacity of 316 mg·g −1 and removal efficiency larger than 95%. The alteration of the characteristics after the adsorption confirmed the adsorption mechanism is the bi-function of surface coordination and precipitation. This novel route is easy handling and energy saving, promising it to be a reliable way to produce biochars with attractive surface properties for environmental decontamination.
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INDUSTRIAL CROPS AND PRODUCTS
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2019
·
IF 4.191
Zhen-xi Zhang,Kai Li,Shan-wei Ma,Min-shu Cui,Qiang Lu,Yong-ping Yang
Phenol is an important phenolic compound widely used in chemical industry. Lignin in lignocellulosic biomass materials has been recognized as a renewable source for phenol production due to its aromatic nature. In the present study, phenol was selectively prepared from fast pyrolysis of biomass using a recyclable magnetic solid base catalyst (K 3 PO 4 /Fe 3 O 4 , MSB) in an atmosphere with low hydrogen content. The study focused on the influence of pyrolysis atmosphere, pyrolysis temperature, catalyst content, and biomass type on the product distribution, as well as the recycle performance of MSB in consecutive pyrolysis experiments. Results suggested that the synergistic effect of MSB catalyst and hydrogen atmosphere significantly improved the formation of phenol. In a hydrogen atmosphere at MSB to biomass ratio of 1, the maximal phenol yield of 4.3 wt% with the selectivity of 17.6% was obtained from poplar wood pyrolysis at 550°C. Pyrolysis experiments with different biomass materials suggested that the phenol formation was positively correlated with biomass lignin content. A three consecutive run experiment indicated that the MSB catalyst had excellent performance on recovery and recycle. In addition, possible synergistic mechanism between MSB and hydrogen atmosphere was proposed.
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SOLAR ENERGY
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2019
·
IF 4.674
Shuang Lu,Yinglin Wang,Chunxia Wu,Yichun Liu,Xintong Zhang
Searching for large-scale, non-Pt, efficient counter electrode (CE) materials is still a key challenge to realize the applications of high-performance dye-sensitized solar cells (DSSCs). Herein, we report the spray fabrication of stable, uniform and efficient CoS counter electrode at temperature no higher than 100 °C from CoS nanoparticles prepared by the ultrasonic spray pyrolysis (USP) method. The as-fabricated USP-assisted CoS CEs exhibit comparable electrocatalytic activity to the traditional thermolyzed Pt CE, generating a power conversion efficiency of 8.6% for unoptimized DSSCs. This CoS CEs also exhibited prominent electrochemical and mechanical stability, uniform electrocatalytic activity at the size of 10 × 10 cm, and good bending durability when deposited on flexible ITO/PEN conductive substrates, manifesting the merits of this USP-based strategy for the development of high-performance non-Pt electrocatalysts.
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SCIENCE OF THE TOTAL ENVIRONMENT
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2018
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IF 4.61
Mengqi Zheng,Yuxing Han,Chunyan Xu,Zhengwen Zhang,Hongjun Han
This study originally investigated the selective adsorption of cyclic organics in APCPW by LAC, corresponding to the change of the bioavailability . As a product from low rank coal, LAC showed more oxygen (O)-containing groups and mesoporous structure than PAC. Adsorption mechanisms were analyzed by equilibrium isotherms and kinetics models combined with physicochemical properties of adsorbent and adsorbates. The results indicated that selectivity of LAC was dominated by chemical interaction and its mesoporous, and was enhanced by hydrophobicity of adsorbates. In addition, PAC and LAC were applied for the treatment of APCPW. Compared with PAC, LAC adsorption exhibited superior removal efficiency of Tph, TOC and TN at 85.90%, 91.15% and 51.64%, respectively. Furthermore, preferential adsorption of biotoxic and bioresistant cyclic organics by LAC was further proved by GC–MS analysis, resulting in increased bioavailability of APCPW. Specifically, LAC exerted sustained detoxication capacity until 86.50% reduction of TU by D. magna evaluation, and lowered toxicity rank (TU = 4.51, classIII) to T. pyriformis than that after PAC adsorption (TU > 10, ClassIV). Meanwhile, biodegradability was also improved by 9.17% after LAC adsorption. Lastly, LAC would exhibit great economic benefits as an alternative for PAC in subsequent process after anaerobic pretreatment .
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LANGMUIR
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2019
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IF 3.683
Dongjin Wan,Lairong Wu,Yongde Liu,Jing Chen,Hailiang Zhao,Shuhu Xiao
In this study, spent bleaching earth (SBE) and pyrolyzed SBE (SBE@C) were tested for their capacity to remove tetracycline hydrochloride (TCH) from aqueous solution. The maximum adsorption capacity obtained by the Langmuir model is 0.114 mmol/g for SBE@C and 0.087 mmol/g for SBE. The deleterious effects of coexisting cations were ranked in a decline: Al3+ > Mg2+ > Na+. The results of various characterization methods show that the adsorption mechanisms mainly included π–π interactions, hydrogen bonding, electrostatic interactions, and changes in physical and chemical properties. After 3 repeated cycles of pyrolysis, the adsorption capacity of SBE@C remained at 85.4%, with SBE@C potentially recycled 21 times before complete loss of adsorption capacity. Furthermore, the problem of secondary pollution caused by SBE and residual oil is resolved by the use of SBE@C. All results indicate that SBE@C is a likely candidate for the treatment of TCH wastewater in the coming practical applications.
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JOURNAL OF THE ENERGY INSTITUTE
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2019
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IF 3.774
Meiyun Chai,Yifeng He,Nishu,Chen Sun,Ronghou Liu
Bio-oil is a multicomponent mixture of more than 400 types of organic compounds, with high water content . Fractionation of bio-oil may be a more efficient approach for primary separation of bio-oil. In this work, to better understand the effect of fractional condensers on bio-oil yield, physicochemical characteristics, compounds distribution and phenols selection during biomass fast pyrolysis process , a semi-automatic controlled fluidized bed reactor biomass fast pyrolysis system with four-stage condensers was developed. Average temperatures of Condensers 1, 2, 3, 4 were 32.39 °C, 26.74 °C, 24.06 °C and 23.68 °C, respectively. And the bio-oil yields of Condenser 1, 2, 3, and 4 were 26.82%, 7.31%, 1.48% and 9.69%, respectively. Bio-oil collected from Condenser 4 had the lowest water content (9.68 wt%), the lowest acidity (pH = 3.67), and the highest HHV (29.2 MJ/kg). The highest relative contents of compounds collected from Condenser 1, 2, 3 and 4 were 1-(4-hydroxy-3-methoxyphenyl)-2-Propanone (6.95%), trans-Isoeugenol (6.63%), Creosol (5.28%), and trans-Isoeugenol (6.69%), respectively. Fractional condensers affected the compounds distribution, but it has a stronger effect on relative heavy compounds (molar mass > 250) and a weaker effect on relative light compounds (molar mass < 200). Fractional condensers were more conducive to the selection of phenols with relative yield of more than 30%. Phenols, acids and furfurans tended to distribute at higher temperature, while alcohols, ethers and hydrocarbons tended to distribute at relative lower temperature, but the difference was small. The research has provided a reference for the production of bio-oil.
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EUROPEAN POLYMER JOURNAL
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2024
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IF 5.8
Sihao Yin,Yirou Du,Wuhua Lv,Yang Jiang,Dong Feng,Yuhui Xie,Delong Xie,Yi Mei
Black phosphorus nanosheets (BPns) have gained widespread attention in the field of flame retardancy due to their highly efficient flame-retardant properties achieved with a low addition rate (e.g., 0.4%). However, the pyrolysis pathways of BP in polymers have not yet been elucidated. This work systematically studies the flame retardancy and pyrolysis behavior of BP in oxygen-containing (polyurethane, PU) and oxygen-free (polypropylene, PP) polymers, distinguishing between the gas-phase and the condensed-phase flame retardant effect of BP. Through slow heating and staged heating methods, the condensed phase and gas phase pyrolysis products of BP in PU and PP at different temperatures are compared in detail. The distinct flame retardant pathways of BP in PU and PP are revealed. The results indicate that the oxidation of BP commences with its reaction with atmospheric oxygen, implying that the condensed-phase flame-retardant effect of BP primarily occurs at the polymer surface. In PP, BP mainly functions as a gas-phase flame retardant. In the condensed phase, BP generates phosphate derivatives that cover the substrate surface, providing solely a physical barrier effect. In PU, while BP demonstrates an outstanding gas-phase flame-retardant effect, it also accelerates the early dehydration carbonization of alcohols within the substrate, resulting in the formation of phosphate ester compounds (P–O–C structure) to bolster the thermal stability of residual carbon. Additionally, the side reactions of BP during catalytic carbonization will decrease the thermal stability of ester bonds in PU. This work lays a theoretical foundation for the development and application of BP-based flame retardant systems.
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ENERGY
·
2016
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IF 4.292
Zi-Qiang Ming,Yun-Quan Liu,Yue-Yuan Ye,Shui-Rong Li,Ying-Ru Zhao,Duo Wang
A new combined method for the pre-extraction of essential oils (EOs) and the uniformly dispersion of alkaline earth metal oxide (AEMO) on pine sawdust (PS) was investigated. EOs were firstly extracted from PS after mixing with a certain amount of AEMO through steam distillation (SD), and then the pretreated PS was utilized in the process of fast pyrolysis to produce the upgraded bio-oil. A maximum extraction yield of EOs was 1.61 wt% from PS mixed with 5 wt% CaO within 300 min, compared with 1.21 wt% from the control (raw PS). The proportion of alcohols in EOs increased significantly when using PS mixed with AEMO. When PS was pretreated by the combined AEMO mixing and SD, the content of hydrocarbons in organic phase of the bio-oil increased significantly while that of acids and C n H m O x decreased. The analysis of physicochemical properties for the bio-oil further demonstrated that the quality of bio-oil was improved based on the new pretreatment method. Furthermore, the maximum bio-oil yield was obtained at pyrolysis temperature of 500 °C in almost all cases.
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JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2016
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IF 3.652
Shurong Wang,Haizhou Lin,Yuan Zhao,Jingping Chen,Jinsong Zhou
Humin, a solid by-product formed during the acid-catalyzed conversion of carbohydrate to platform chemicals, can be further utilized by pyrolysis technology. In this study, two humins derived from glucose (humin-g) and xylose (humin-x) were characterized by elemental analysis, FTIR and 13 C NMR. Both humins were polymers rich in furan rings, and their carbon contents were more than 66%. Thermogravimetry and pyrolysis kinetic analyses based on Flynn-Wall-Ozawa and Friedman methods suggested that the activation energies for both humins increased as their conversion rates increased. At low conversion rates, the activation energy of humin-x was higher than that of humin-g, but this was reversed at high conversion rates. The results suggest that humin-g has better thermal stability following the removal of weak linkages at low temperature. Finally, Py-GC/MS was employed to study the product distribution from humin pyrolysis. The mechanisms for formation of typical products and the influence of temperature on product distribution are discussed.
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Environmental Progress & Sustainable Energy
·
2016
·Vol. 35
·期 3
·840-846
·
IF 1.631
Wei Shi
Nitrogen-doped coralline-like structure porous carbon (NC-PANI) was prepared through a simple urea-assisted pyrolysis of low-cost and environmental friendly polyaniline (PANI) nanofibers. The urea acts as nitrogen donor and activating agent in the PANI carbonization, to generate the porous carbon with high nitrogen content (10.08 wt %), high surface area (673.7 m 2 /g), and suitable pore size. In addition, the electrical conductivity of NC-PANI is better than that of pristine PANI. With such intrinsic characteristics, the as-prepared novel NC-PANI is highly desirable for energy storage and conversion applications. © 2016 American Institute of Chemical Engineers Environ Prog, 35: 840–846, 2016
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
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2017
·Vol. 409
·期 10
·2531-2537
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IF 3.431
Cheng Hao,Wu Shubin,Huang Jinbao,Zhang Xiaohua
Although o -quinonemethide (6-methylene-2,4-cyclohexadien-1-one) has been proposed as a key intermediate in char formation during the pyrolysis of guaiacol (2-methoxyphenol), direct evidence of this (e.g., spectroscopic data) has not yet been provided. Using in situ FTIR spectroscopy, the pyrolysis of guaiacol was investigated from 30 °C to 630 °C at 40 °C/min. The IR profiles showed direct evidence of o -quinonemethide production at about 350 °C, which vanished rapidly at around 420 °C in the vapor phase, indicating char formation. In addition, at 400 °C, salicyl aldehyde was observed, which decomposed slowly at about 500 °C. In combination with the known products of guaiacol pyrolysis, these results allowed the major reaction pathways of guaiacol pyrolysis to be discerned. Density functional theory calculations were performed, and the results were found to be in good agreement with the experimentally obtained IR profiles. These findings provide guidance on how to suppress secondary reactions of guaiacol during lignin pyrolysis.
On-line analysis of pyrolysis process of guaiacol using in situ FTIR
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BIORESOURCE TECHNOLOGY
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2015
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IF 4.494
Bo Zhang,Zhaoping Zhong,Paul Chen,Roger Ruan
Chemical vapor deposition with tetra-ethyl-orthosilicate as the modifier was applied to deposit the external acid sites of HZSM-5, and the modified HZSM-5 samples were used for the microwave-assisted catalytic fast pyrolysis (MACFP) of biomass for bio-oil production. The experimental results showed that the external acid sites of HZSM-5 decreased significantly when SiO 2 deposited amount increased from 0% to 5.9%. For product distribution, the coke yield decreased, the oil fraction yield decreased at first and then increased, and the yields of water and gas first increased and then decreased over the range of SiO 2 deposited amount studied. For chemical compositions in oil fraction, the relative contents of aliphatic hydrocarbons, aromatic hydrocarbons and oxygen-containing aromatic compounds first increased to maximum values and then decreased, while the relative content of oxygen-containing aliphatic compounds first decreased and then increased with increasing SiO 2 deposited amount.
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