Journal of Cleaner Production
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2020
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IF 7.246
Limiao Cai,Jie Sun,Lihua Cui,Yanzi Jiang,Zhujian Huang
Piggery wastewater sludge is rich in organic matter but contains pollutants that are harmful to the environment and ecology, such as heavy metals . In this paper, a novel process for hazard-free treatment and resource utilization of piggery wastewater sludge was proposed. Technique combining Fe(II) coagulation, hydrothermal reaction and pyrolysis (CHP) was used to stabilize heavy metals (HMs) in sludge, and the adsorption performance of the recycled product to tylosin (TYL) was studied. SV30 (Sludge Volume 30 min) of sludge decreased from 97% to 30% after Fe(II) coagulation and water content of sludge decreased from 97% to 30% after hydrothermal treatment. After CHP treatment, the residue fraction of Cd, Pb, Cu, Zn, Cr and Ni increased by 12.1%, 67.3%, 12.4%, 15.4%, 58.5%, 2.8% respectively. With raising Fe 2+ dosage, residual state of each heavy metal increases. Sludge biochar (SBC) generated after CHP process is a kind of mesoporous composite composed of goethite , quartz, biochar and polymer, and showed a high adsorption capacity for tylosin, and the process of which can be well expressed by Langmuir adsorption isotherm ( R 2 = 0.947). The maximum theoretical adsorption capacity of SBC for TYL can be obtained by pyrolysis at 600 °C, which can reach 58 mg g −1 .
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BIORESOURCE TECHNOLOGY
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2020
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IF 7.539
Yang An,Arash Tahmasebi,Xiaohui Zhao,Tawanda Matamba,Jianglong Yu
This study addresses the in-situ microwave catalytic reforming of volatile matter from palm kernel shell (PKS) over iron-loaded activated carbon (Fe/AC) catalysts. The impacts of catalyst composition on the secondary gas-phase reactions and distribution of products were studied at 500 °C. It was found that the Fe/AC catalyst promoted the yield of light gases. Using the 1%-Fe/AC catalyst, the yield of gaseous fraction peaked at 37.09 wt%. The selectivity of the deoxygenated products was promoted in the presence of Fe. Catalytic reforming of PKS pyrolysis vapors over Fe/AC drastically enhanced the generation of phenol and H 2 , the concentrations of which reached 75.09 area% and 75.12 vol%, respectively. Catalytic pyrolysis of syringol and guaiacol as model compounds showed that Fe/AC catalyst promoted the demethoxylation and deoxygenation reactions to selectively generate phenol which was explained by oxophilic reactivity of the active Fe sites.
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JOURNAL OF HAZARDOUS MATERIALS
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2020
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IF 9.038
Xiaojuan Li,Fengzhen Liao,Lanmei Ye,Lizhi Yeh
In this study, based on the extensive discussion of the phase transformation process of metal-organic frameworks (MOFs)——MIL-88A(Fe) under thermal treatment, the catalytic performance of MIL-88A-derived iron/carbon (FexC) composites on persulfate (PS) activation for phenol degradation was investigated. FexC-600 ( γ -Fe 2 O 3 /C) exhibited a superior catalytic activity on PS activation for phenol degradation due to higher carbon content, more sp 2 -hybridized structure, carbonyl group and defective sites in composites, in which 98.23% of phenol (20 mg/L) was degraded after 60 min with 0.3 g/L catalyst and 0.3 g/L PS at ambient pH (6.1). The phenol degradation experiments and mechanism studies revealed that there was a catalytic synergism between iron oxides and carbon component in FexC 400-600 composites. Moreover, sulfate radicals (SO 4 − ), hydroxyl radical (•OH), singlet oxygen ( 1 O 2 ) and interfacial electron transfer process all involved in the degradation of phenol by FexC 400-600 composites, but the 1 O 2 -mediated non-radical oxidation was the dominant pathway rather than reactive radicals. Finally, the possible mechanism of PS activation on FexC 400-600 composites was proposed. This work discusses the synergistic catalytic mechanism of FexC composites on PS activation, and favors to provide a better understanding of the metal species and carbon component interaction in iron/carbon-based materials.
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ENERGY & FUELS
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2019
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IF 3.021
Yang Li,Huan Liu,Kangxin Xiao,Minghao Jin,Han Xiao,Hong Yao
In this study, the effects of carbohydrates, proteins, and lipids on the combustion and pyrolysis characteristics of hydrochar were investigated by adding pure substances during hydrothermal carbonization (HTC) of typical food waste to magnify their effects on hydrochar. The experimental results demonstrated that carbohydrates enhanced the homogeneousness and thermal stability of hydrochar. Proteins showed minor effects on their combustion behavior. While the proportion of lipid in feedstock increased, its derived hydrochar exhibited a higher volatile content (74.51%), lower activation energy (101.1 kJ/mol), and more violent combustion process of hydrochar. An ingenious method of acetone leaching was applied to elute the attachments on the surface of hydrochar and further investigate their chemical constituent and influence mechanism of lipids. When the lipid content in feedstock increased during HTC, the attachments on hydrochar were verified to be dodecanoic acid and dodecylamide, which were the main chemical constituents of the volatile matter in hydrochar. They rapidly decomposed and burned at a lower temperature range (141–256 °C), resulting in the diminution of the ignition temperature (193 °C) and combustion activation energy. The results can offer referential information for improving the combustion and pyrolysis characteristics of hydrochar from food waste.
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WASTE MANAGEMENT
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2023
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IF 8.1
Danni Li,Rui Shan,Jing Gu,Yuyuan Zhang,Xianhai Zeng,Lu Lin,Haoran Yuan,Yong Chen
To relieve the secondary contamination of heavy metals (HMs), the synergistic effect of co-pyrolysis of textile dyeing sludge (DS)/litchi shell (LS) and CaO on the migration of HMs was demonstrated in this study. The proportions of Cu, Zn, Cr, Mn, and Ni in the F4 fraction increased to 75%, 55%, 100%, 50%, and 62% at the suitable CaO dosages. When 10% CaO was added, the RI value of DLC-10% was reduced to 7.89, indicating low environmental risk. The characterizations of the physicochemical properties of biochar provided support for the HMs immobilization mechanism. HMs combined with inorganic minerals or functional groups to form new stable HMs crystalline minerals and complexes to achieve immobilization of HMs. The pH value and pore structure also play an important role in improving the immobilization performance of HMs. In conclusion, the results provided a new direction for the subsequent harmless treatment of HMs-enriched waste.
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JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
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2023
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IF 6.1
Yuchen Jiang,Kang Zhang,Chao Li,Yuewen Shao,Lijun Zhang,Shu Zhang,Chuanjun Leng,Dong Wang,Zhenhua Cui,Xun Hu
Metal/biochar is an important catalyst with feature of easy recovering of metal via combustion of biochar carrier. During preparation of metal/biochar, interaction of metal with biochar affects evolution of pyrolytic products and dispersion of metal. Heating mode could influence interaction of metal with pyrolytic products. This was investigated by pyrolysis of sawdust loaded with nickel acetate at 400 or 600 °C with furnace and microwave heating, respectively. The results showed that cracking of biochar and volatiles was effectively promoted with Ni, generating more gases while reducing aliphatic organics and heavy phenolics in bio-oil. The enhanced cracking facilitated aromatization in microwave heating, forming biochar of higher thermostability and gases with more hydrogen. However, the furnace heating at 600 °C formed Ni/biochar of more developed pores than from microwave heating (409.1 versus 385.0 m 2 g −1 ). Microwave heating could induce merging of micropores on biochar, resulting in migration and aggregation of Ni. This led to lower capability for chemical adsorption of hydrogen and dispersion of nickel, further leading to inferior activity of Ni/biochar from microwave heating for hydrogenation of vanillin or furfural. The in-situ IR characterization of the pyrolysis showed the furnace heating reserved more oxygen-containing organics and aliphatic structures, promoting dispersion of nickel.
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CHEMICAL ENGINEERING JOURNAL
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2023
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IF 15.1
Wei Feng,Mo Zheng,Jin Bai,Xianxian Zhang,Chuang Wu,Zhenxing Guo,Lingxue Kong,Zongqing Bai,Wen Li
Understanding the effects of co-pyrolysis synergies between low-rank coal and high-density polyethylene (HDPE) on the carbon structure evolution in char and the relationship between char structure and chemical bonds evolution is very needed. A combination of ReaxFF MD and experimental approaches provides an opportunity for fully understanding the dynamic profiles of char structures and coking trends during co-pyrolysis process of coal and HDPE. In this work, consistent conclusions were obtained from fixed-bed experiments and ReaxFF MD simulations in product distribution during both individual coal pyrolysis and co-pyrolysis at different temperatures. The ReaxFF MD simulation results reveal that adding HDPE partially inhibited the coking process of coal char. The RDF results indicated higher order degree and aromaticity exist in coal/HDPE(7:3)-Char when compared to those in coal-Char, which agrees well with the findings from XRD and FTIR approaches. By analyzing the evolution of C=C, C=O, C-O, C( sp 2 )-C( sp 3 ), C( sp 3 )-C( sp 3 ) and C( sp 2 )-H bonds in C 40 + fragments during secondary simulations of co-pyrolytic char, it was observed that the structural order and aromaticity of co-pyrolytic char increase with temperature, and the oxygen-containing bonds are the initial recombination sites for char formation. These findings provide rich theoretical information to complement the understanding of char structure in co-fed systems and the interaction between coal and HDPE blend.
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Journal of Environmental Chemical Engineering
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2023
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IF 7.7
Jiashu Liu,Lin Zhao,Hongzhi Geng,Bin Wang,Xuejiao Tong,Yihan Li,Daying Chen,Peizhe Sun,Yongkui Yang
Trichloroethylene (TCE) commonly exists in contaminated water as a persistent toxic pollutant . The advanced oxidation of persulfate (PS) is a promising method for degrading organic pollutants . Heterogeneous Fe-carbon composites prepared by pyrolysis with metal–organic frameworks (MOFs) have attracted attention. However, the intrinsic relationship between the physicochemical properties and catalytic performance of MOF-derived carbon compounds via PS is unclear. This study investigates TCE removal by Fe-MOF-derived carbon (MFC) with PS. The effects of the precursor template structure, pyrolysis temperature, and coexisting substances on TCE removal over the MFC/PS system are examined. Fe-MOF-derived from different precursor templates presented different TCE removal rates of 75.2–85.0%. The pyrolysis temperature of MFC alters the pore size, phase composition, and other properties, thereby affecting electron transport in the materials and catalyzing the degradation process. The total TCE removal reached 85.8% with MFC600, derived from MF88B and pyrolyzed at 600 ℃. This catalyst demonstrated excellent performance for PS degradation over a wide pH range (3−9). Moreover, free-radical and nonradical pathways coexist in the MFC600/PS system. During the TCE degradation process, oxygen vacancies, Fe species (Fe 0 , Fe 3 N, Fe 3 C, and Fe 3 O 4 ), and N species (pyridinic N and graphitic N) were active centers in the material and played a major role in catalytic degradation. They participated in the subsequent generation of HO•, SO 4 • - , and •O 2 - , and 1 O 2 . Furthermore, a possible degradation mechanism is proposed. This study elucidates the control of the physicochemical properties of carbon-based catalysts by exploiting MOF diversity.
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WASTE MANAGEMENT
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2023
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IF 8.1
Qingyu Liu,Bo Peng,Ning Cai,Yinhai Su,Siyu Wang,Peng Wu,Qi Cao,Huiyan Zhang
Upcycling waste plastics into valuable carbon nanotubes (CNTs) and hydrogen via catalytic pyrolysis is a sustainable strategy to mitigate white pollution. However, real-world plastics are complex and generally contain organic impurities, such as cellulose, which have a non-negligible impact on the catalytic pyrolysis process and product distribution. In this study, cellulose was chosen as a model compound to distinguish the effects of oxygen-containing components on the CNTs and hydrogen production during the catalytic pyrolysis of waste polypropylene. Different amounts of cellulose were mixed with polypropylene to regulate the O/C mass ratio of the feedstock, and the relationship between the O/C mass ratio and the yield of products has been built quantificationally. The results revealed that the relative content of CNTs increased to over 95%, and the stability and purity of carbon deposition increased accordingly when the O/C mass ratio is 0.05. This could be ascribed to the etching effects caused by small amounts of H 2 O and CO 2 on amorphous carbon. However, further increasing the amount of cellulose caused the deactivation of the Fe-Ni catalyst. This not only decreased the carbon yield but had an adverse impact on its morphology and graphitization, leading to the increase of amorphous carbon. This study can provide fundamental guidance for the efficient utilization of waste plastics that take advantage of organic impurities in waste plastic to promote the formation of high-purity CNTs.
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JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2023
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IF 6
Chengxuan Zhou,Danni Deng,Chao Huang,Yu Xie,Hang Dong,Yujiao Wen,Bo Li,Zhi Zhou,Wei Luo,Zhonghua Zhou
The search for cost-effective, high-performance catalysts is crucial in catalytic co-pyrolysis. Different Fe-Mo@X catalysts (X = Al 2 O 3 , MgO) and reaction temperatures (600 ℃, 700 ℃, 800 ℃, 900 ℃) were tested to optimize hydrogen production and carbon quality while also exploring CNTs degradation performance. The results indicate that both catalyst type and operating parameters are highly dependent on the growth of carbon nanotubes and hydrogen. The FeMo@Al 2 O 3 catalyst exhibits superior catalytic activity attributed to its more abundant mesoporous structure and higher specific surface area. Specifically, FeMo@Al 2 O 3 achieved the highest yield of carbon nanotubes (84.42%) at 700 ℃, and attained the maximum hydrogen yield (49.57%) at 900 ℃. However, the CNTs synthesized from FeMo@MgO exhibited fewer defects, higher graphitization degree and purity (Raman and TPO). CNTs/MgO significantly enhanced the degradation efficiency of Clothianidin by virtue of their superior electron transport properties and chemical bonding between MgO and CNTs.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2023
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IF 22.1
Bin Chen,Zining Zhou,Yuze Li,Kok Bing Tan,Youting Wang,Xiaoping Rao,Jiale Huang,Xiaodong Zhang,Qingbiao Li,Guowu Zhan
Herein, biomass-derived activated carbon (bio-AC) was synthesized using rice husk as a biotemplate and natural carbon source. After immobilization of Ni, the supported Ni/bio-AC showed excellent catalytic activity in the pyrolysis of fatty acids to paraffin-based biodiesel in H 2 -free and solvent-free conditions, corresponding to the conversion of 99.6% and a total alkane yield of 95.1%, including 88.9% heptadecane. Based on comprehensive characterizations, the calculated turnover frequency of Ni/bio-AC was 3.9 times that of conventional Ni/AC. Significantly enhanced olefin selectivity was further obtained by N-doping of Ni/bio-AC, which was attributed to the inhibition of -COO* dissociation by the Ni-N sites. The possible catalytic reaction pathways from stearic acid to heptadecane via aliphatic alcohol as a reaction intermediate were investigated. Besides, efficient conversions of saturated and unsaturated plant oils were also achieved over Ni/bio-NAC catalysts in Py-GC/MS through pulsed catalytic pyrolysis manner, showing a promising prospect for sustainable biofuels and chemical production.
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MOLECULES
·
2023
·Vol. 28
·期 10
·4088
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IF 4.6
Feng Li,Wenzhi Lv,Dena Huang,Chenglu Zeng,Runping Wang
The molecular weight of lignin extracted from lignocellulosic biomass is an important factor in determining its valorization in industrial processes. Herein, this work aims to explore the extraction of high molecular weight and bioactive lignin from water chestnut shells under mild conditions. Five kinds of deep eutectic solvents were prepared and applied to isolate lignin from water chestnut shells. The extracted lignin was further characterized with element analysis, gel permeation chromatography, and Ultraviolet-visible and Fourier-transform infrared spectroscopy. The distribution of pyrolysis products was identified and quantified with thermogravimetric analysis—Fourier-transform infrared spectroscopy and pyrolysis-gas chromatograph-mass spectrometry. The results showed that choline chloride/ethylene glycol/p-toluenesulfonic acid (1:1.8:0.2 molar ratio) exhibited the highest fractionation efficiency for lignin (84.17% yield) at 100 °C for 2 h. Simultaneously, the lignin showed high purity (90.4%), high relative molecular weight (37,077 g/mol), and excellent uniformity. Furthermore, the aromatic ring structure of lignin remained intact, consisting mainly ofp-hydroxyphenyl, syringl, and guaiacyl subunits. The lignin generated a large number of volatile organic compounds during the depolymerization process, mainly composed of ketones, phenols, syringols, guaiacols, esters, and aromatic compounds. Finally, the antioxidant activity of the lignin sample was evaluated with the 1,1-diphenyl-2-picrylhydrazyl radical scavenging assay; the lignin from water chestnut shells showed excellent antioxidant activity. These findings confirm that lignin from water chestnut shells has a broad application prospect in valuable chemicals, biofuels and bio-functional materials.Keywords:deep eutectic solvent;lignin;water chestnut shell;antioxidant activity;pyrolysis
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