WATER AIR AND SOIL POLLUTION
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2022
·Vol. 233
·期 11
·1-12
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IF 2.984
Wang Xuejia,Yan Peng,Yang Xue,He Mingqi
Anionic surfactant wastewater has an irreversible effect on aquatic animals and plants. In this paper, the oxidation of sodium dodecylbenzene sulfonate (SDBS) by electro-Fenton system was researched. The results demonstrated that HO 2 · had a weak ability to oxidize SDBS; ·OH was the primary active substance for oxidizing SDBS. The broken bond sites of SDBS molecules oxidized by the active substances were analyzed by using the concept density functional theory. The calculation results indicated that ·OH initially attacked the C3-C11 bond in the SDBS molecule, and then ·OH underwent addition reactions, forming two typical structures: aromatic sodium p-hydroxybenzene sulfonate and aliphatic linear alkanes. Phenol and sodium dodecyl sulfate (SDS) were selected to study their oxidation behaviors in the electro-Fenton system. It can reflect the oxidation process of the products after the SDBS molecule was broken. The main active substance for oxidizing phenol in the electro-Fenton cathode chamber was ·OH, but the main active substance for oxidizing SDS was HO 2 ·. Unlike the ·OH produced by the cathode, the Pt(·OH) produced by the anode had no effect on the removal of SDBS. Nevertheless, Pt(·OH) exhibited an excellent oxidation effect on SDBS bond-breaking products. The research results clarified the mechanisms of SDBS oxidation in electro-Fenton system and the direction of regulation for the reaction path. It is believed that promoting the ·OH generated at the cathode makes SDBS bond breakage a key step in the electro-Fenton oxidation of SDBS. It provided a theoretical basis for enhancing the current efficiency of the system.
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JOURNAL OF HAZARDOUS MATERIALS
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2022
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IF 14.224
Qiaoqiao Wang,Hehe Qin,Jinhong Fan,Haijiao Xie
The heterogeneous Fenton-like reaction (HeFR) has always been a research focus for environmental applications. However, it has long been difficult to reach a consensus on the reaction mechanism because the process of metal ions dissolution and its role were not well understood. In this paper, we propose the courses of organics-mediated coordination or/and reduction dissolution of ferric hydroxide to initiate the autocatalytic kinetics of phenol degradation and illustrate it through density functional theory (DFT) and experiments. With the increase of hydrogen peroxide concentration, the degradation of phenol changes from autocatalytic kinetics to first-order kinetics. Furthermore, a novel "limit segmentation method" initiated by us indicates that homogeneous reaction plays a decisive role in the phenol degradation process. The dominant roles of the reactive organics in both iron dissolution and the iron cycle and of the homogeneous reaction in the whole degradation process in the ferric hydroxide-based HeFR system are brand-new insights that pave the pathway for future research.
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CARBOHYDRATE POLYMERS
·
2022
·
IF 10.723
Xiaoli Zhang,Qingli Qu,Anquan Yang,Jing Wang,Weixia Cheng,Yankang Deng,Aying Zhou,Tao Lu,Ranhua Xiong,Chaobo Huang
The emergence, spread and difficult removal of bacteria biofilm, represent an ever-increasing persistent infections and medical complications challenge worldwide. Herein, a self-propelled system Prussian blue micromotor (PB MMs) were constructed by gas-shearing technology for efficient degradation of biofilms by combining chemodynamic therapy (CDT) and photothermal therapy (PTT). With the interpenetrating network crosslinked by alginate , chitosan (CS) and metal ions as the substrate, PB was generated and embedded in the micromotor at the same time of crosslinking. The micromotors are more stable and could capture bacteria with the addition of CS. The micromotors show excellent performance, containing photothermal conversion, reactive oxygen species (ROS) generation and bubble produced by catalyzing Fenton reaction for motion, which served as therapeutic agent could chemically kill bacteria and physically destroy biofilm. This research work opens a new path of an innovative strategy to efficiently remove biofilm.
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JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2022
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IF 6.437
Linlin Yi,Hong Yao,Xian Li,Zhenzhong Hu,Liu Shi,Yangwei Wu
The catalytic pyrolysis is a promising method for obtaining value-added aromatics, especially benzene, toluene and xylene (BTX). For different biomass-based materials, the dual catalyst system composed of CaO-based and ZSM-5-based catalysts showed an obvious selectivity for the BTX production. This study chose CaO derived from organic calcium precursors (Org-CaO) and nano-sized ZSM-5 (NZSM-5), and comprehensively investigated the effects mechanism of biomass components on the formation pathways of BTX via Py-GC/MS. Under the catalysis of NZSM-5, the BTX yields were only 7.8–30%. The BTX yields on Org-CaO/NZSM-5 were as follows: lipid (63.1%) > hemicellulose (55.4%) > cellulose (40.2%) > lignin (21.7%). Typical pyrolysis intermediates were employed to quantitatively reveal the intermediate reactions. Pyrolysis intermediates exhibited low BTX-forming reactivity over NZSM-5. The pre-catalysis of Org-CaO selectively converted part undesired intermediates (fatty acids and furans) into BTX precursors (short-chain olefins and ketones), facilitating the remarkable increase of BTX yield in the subsequent NZSM-5 catalysis process. However, the pre-catalysis of Org-CaO can hardly make the ring opening reaction of lignin-derived phenolic compounds that have very low reactivity on NZSM-5, and thence high-lignin biomass obtained low BTX production during catalytic pyrolysis by Org-CaO/NZSM-5. These findings afforded a new route for increasing the BTX yields by directionally forming BTX precursors or controlling biomass components.
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POLYMER DEGRADATION AND STABILITY
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2022
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IF 5.204
Dandan Chen,Benben Liu,Xu Wang,Xiangmei Li,Xingyan Xu,Jiyu He,Rongjie Yang
In order to improve the thermal stability, flame retardancy and dielectric properties of benzoxazine resin, benzoxazine resins with different content of 4,4′-(hexafluoroisopropylidene) diphthalic dianhydride(m-EFDA) were prepared by crosslinking alkynyl groups. The results showed that benzoxazine can improve the processing window of m-EFDA, while m-EFDA was beneficial to improve the thermal stability and dielectric properties of benzoxazine resins. The T d5% of PBZFI-50 reached 418.2°C, T d10% was up to 457.3°C, D k was 2.89 and D f was as low as 0.013 at 1MHz. The chemical structures of volatile products from the pyrolysis of benzoxazines resin at different temperatures were identified by TG-FTIR and Py-GC/MS, and the promoting effect of m-EFDA on improving the thermal stability was confirmed. Compared with pure benzoxazine resin, the resin containing m-EFDA has great performance improvement, which is expected to be used as high temperature and low dielectric material in aerospace and microelectronics field.
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Biomed Research International
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2022
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IF 3.246
Bingmin Wu,Yange Wang,Lishan Zeng,Wengkun Li,Lin An,Jingyan Li,Ruoting Zhan,Huasheng Kang,Li Liu,Ying Lin,Guifang Zhang
In this paper, Lignosus rhinocerotis (Cooke) Ryvarden ( L. rhinocerotis ) cultivated in rice medium (LRR) and in sawdust medium (LRS) was harvested. Then, in terms of the LRR, LRS, and wild L. rhinocerotis (LRW), the total flavonoid contents, total polyphenol contents, total polysaccharide contents, and metabolites were detected; antioxidants of their aqueous extracts and anti-inflammatory of their polysaccharides were performed. In addition, the possible mechanism of the polysaccharides of L. rhinocerotis inhibiting lung damage was elucidated. The results showed that 32 compounds were characterized in L. rhinocerotis , including flavonoids, terpenoids, lignans, and steroids and there were 20 compounds in cultivated and wild L. rhinocerotis ; LRR has the highest total polyphenol and flavonoid contents, as well as ABTS and DPPH scavenging capacity. The total polysaccharide contents and the FRAP scavenging capacity of wild L. rhinocerotis were higher than those of cultivated L. rhinocerotis . The inhibition of polysaccharides of LRW (PLRW) on LPS-induced MRC-5 damage was stronger than that of the polysaccharides from cultivated L. rhinocerotis . The PLRW may alleviate lung damage by inhibiting the NLRP3 pathway and thereby suppressing the inflammatory response. In summary, both cultivated and wild L. rhinocerotis are abundant in bioactive components and have antioxidant and anti-inflammatory activities.
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ACS Catalysis
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2022
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IF 13.7
Ping He,Qisong Yi,Huawei Geng,Yuanchao Shao,Meng Liu,Zhijie Wu,Wenhao Luo,Yuanshuai Liu,Valentin Valtchev
Liquid-phase hydrodeoxygenation (HDO), catalyzed by metal or metal-acid sites, provides an effective catalytic strategy to remove oxygen-containing functionalities of lignin-derived phenolic compounds on the route to fuels and chemicals. Developing the catalyst with high activity and stability is crucial for such a chemical process but still remains a significant challenge. In this contribution, highly dispersed subnanometric Ru metal clusters (<1.5 nm) encapsulated in the cavities of MWW zeolites, including HMCM-22 and its siliceous analog ITQ-1, have been developed for the HDO of guaiacol, an important lignin-derived phenolic monomer, in an apolar liquid phase under mild conditions (160 °C, 3 MPa H2). We validate the effective encapsulation of Ru metal clusters in ITQ-1 and HMCM-22 zeolite cavities via complementary characterization methods. The detailed reaction pathways of the HDO of guaiacol are depicted by using guaiacol, phenol, and anisole as reactants. The subnanometric Ru metal clusters confined in MWW zeolite thin layers (20–30 nm in thickness) show remarkable enhancement in HDO activity compared to the large metal particles. The close proximity between Ru metal clusters and Brønsted acid sites (BAS) confined in zeolite constraints delivers a synergistic effect, leading to an additional enhancement in catalytic activity as well as product selectivity. The super stability of the ultrafine Ru metal clusters against sintering and leaching after successive catalytic runs is achieved. The well-defined mono- or bifunctional Ru-containing MWW zeolite catalysts enable the fundamental understanding of HDO of lignin-derived phenolic compounds in the apolar liquid phase and also provide a prototype for the design of superior catalysts for other energy-related transformations.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2022
·
IF 9.965
Mengmeng Xu,Yuan Liu,Wanru Luo,Fangrong Tan,Donghua Dong,Weichang Li,LinGe Wang,Qianqian Yu
A multi-functional nanocatalytic system based on combined therapies has attracted considerable research attention in recent years due to its potential in the treatment of cancer. Herein, ZnO 2 @ [email protected] nanoparticles (NPs) based on hydroxyl radical (•OH) mediated chemodynamic therapy (CDT) and glucose-exhausting starvation therapy (ST) were constructed. Specifically, in the acidic tumor microenvironment (TME), the pH responsive decomposition of the shell ZIF-67 triggered the release of the Fenton-like catalyst Co 2+ , after which the exposed zinc peroxide (ZnO 2 ) reacted with H 2 O (H + ) to generate O 2 and hydrogen peroxide (H 2 O 2 ). The generated O 2 could alleviate hypoxia in the TEM and interact with ultra-small Au NPs originally coated on ZnO 2 to catalyze intracellular glucose and to produce another source of H 2 O 2 . While the glucose consumption caused the starvation of tumor cells, the generated H 2 O 2 from dual sources reacted with the catalyst Co 2+ to generate highly toxic •OH for CDT. Systematic in vitro and in vivo experiments were carried out to evaluate this nanocatalytic system, and the results showed an enhanced efficacy of this cancer therapy.
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JOURNAL OF ENVIRONMENTAL MANAGEMENT
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2022
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IF 8.91
Kaidi Hu,Jianlong Li,Tianye Zhao,Qiao Zhou,Qin Li,Xinjie Hu,Guoquan Han,Shuhong Li,Likou Zou,Shuliang Liu
As a major intermediate metabolite of synthetic pyrethroids , the occurrence of 3-phenoxybenzoic acid hinders the decomposition of the parent pesticide and poses uncertain risks to environmental ecology and living organisms. Strain Aspergillus oryzae M-4 was previously reported to degrade 3-PBA and several substances were identified as downstream transformation products (TPs). But the mechanism underlying the cleavage of ether bond remains largely unclear. Here, we attempted to address such concern through identifying the peripheral TPs and analyzing transcriptomics, coupled with serial batch degradation experiments. Analysis results of chromatographic/mass spectrometry suggested that 3-PBA underwent twice hydroxylation , to yield mono- and dihydroxylated 3-PBA successively. In parallel, a mutual transformation between 3-PBA and 3-phenoxybenzyl alcohol (3-PBOH) also existed. The proposal of peripheral pathway represents an important advance towards fully understanding the whole 3-PBA metabolism in M-4. A specific altered metabolization was found for the first time, that is, resting cells of M-4 skipped the reduction step and initiate hydroxylation directly, by comparison with growing cells. Transcriptome analysis indicated that 3-PBA induced the up-regulation of genes related to energy investment, oxidative stress response, membrane transport and DNA repair. In-depth functional interpretation of differential expression genes suggested that the generation 3-PBOH and hydroxylated 3-PBA may be due to the participation of flavin-dependent monooxygenases (FMOs) and cytochrome P450 (CYP450), respectively. This study provides new insight to reveal the biodegradation mechanism of 3-PBA by A . oryzae M-4.
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SCIENCE OF THE TOTAL ENVIRONMENT
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2022
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IF 10.753
Ge Song,Pei Su,Qizhan Zhang,Xuechun Wang,Minghua Zhou
2,4-Dichlorophenol (2,4-DCP) widely exists in many industrial wastewaters and is considered a priority pollutant due to its high toxicity. In this work, we proposed a UV/sulfite process without aeration for high-efficiency dechlorination and enhanced mineralization. The UV/sulfite system significantly improved the removal of 2,4-DCP (93.33 % in 60 min) and dechlorination rate (85.13 % in 60 min) compared with UV alone and sulfite alone, and the synergistic factor was 6.59. The UV/sulfite system without aeration improved the mineralization rate (49.80 %) compared with the nitrogen aeration system. UV/sulfite was a reduction-oxidation coupled process and was more suitable for neutral and alkaline conditions. Reducing species (hydrated electrons and H • ) made 2,4-DCP dechlorinate to form dechlorination products such as p -chlorophenol (4-CP), o -chlorophenol (2-CP), and phenol, which were further mineralized by oxidized species (SO 4 •- ). UV/sulfite remained highly efficient in the presence of coexisting ions and under different water quality conditions. This process was also suitable for removing a wide range of chlorinated organic compounds. The UV/sulfite process without aeration can achieve high dechlorination and enhanced mineralization with simple operation and low cost (1.78 $·m −3 order −1 ), which has a broad and cost-effective application prospect in removing refractory halogenated organic pollutants.
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MOLECULES
·
2022
·Vol. 27
·期 22
·7880
·
IF 4.927
Shihao Lv,Xiaoli Lin,Zhenzhong Gao,Xianfeng Hou,Haiyang Zhou,Jin Sun
In this study, a two-step method was used to realize the liquefaction of waste sawdust under atmospheric pressure, and to achieve a high liquefaction rate. Specifically, waste sawdust was pretreated with NaOH, followed by liquefaction using phenol. The relative optimum condition for alkali–heat pretreatment was a 1:1 mass ratio of NaOH to sawdust at 140 °C. The reaction parameters including the mass ratio of phenol to pretreated sawdust, liquefaction temperature, and liquefaction time were optimized by response surface methodology. The optimal conditions for phenol liquefaction of pretreated sawdust were a 4.21 mass ratio of phenol to sawdust, a liquefaction temperature of 173.58 °C, and a liquefaction time of 2.24 h, resulting in corresponding liquefied residues of 6.35%. The liquefaction rate reached 93.65%. Finally, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) were used to analyze untreated waste sawdust, pretreated sawdust, liquefied residues, and liquefied liquid. SEM results showed that the alkali–heat pretreatment and liquefaction reactions destroyed the intact, dense, and homogeneous sample structures. FT-IR results showed that liquefied residues contain aromatic compounds with different substituents, including mainly lignin and its derivatives, while the liquefied liquid contains a large number of aromatic phenolic compounds. XRD showed that alkali–heat pretreatment and phenol liquefaction destroyed most of the crystalline regions, greatly reduced the crystallinity and changed the crystal type of cellulose in the sawdust.Keywords:waste sawdust;alkali–heat pretreatment;liquefaction;response surface methodology;residual content
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FUEL
·
2022
·
IF 8.035
Zhaoyang Qi,Songyu Li,Yaxin Cai,Rongkai Cui,Jie Chen,Changshen Ye,Ting Qiu
Methyl ethyl carbonate (EMC) is the primary raw material for the electrolyte of lithium-ion batteries. It is mainly prepared by the transesterification reaction of dimethyl carbonate (DMC) and EtOH. However, homogeneous alkaline catalysts such as sodium alcohol commonly used in industry are easy to deactivate and challenging to separate and recover. Therefore, the alkaline ionic liquid decorated zeolitic imidazolate frameworks (IL@ZIFs) heterogeneous catalysts were prepared using a simple method with DBU as an inducer. In the synthetic route of IL@ZIFs, the ligand of ZIFs can form an ionic liquid with DBU, and deprotonated ligands will rapidly coordinate with metal ions at room temperature. The DBU can also play the structural guidance and stabilizer, which is conducive to the rapid and effective preparation of ZIFs materials. Meanwhile, the DBU, which has a large molecular diameter, will be trapped in the pore cage and can combine with other protic materials (imidazole, triazole, 2-methylimidazole, phenol, etc.) to form alkaline ionic liquids. The prepared DBU-IL@ZIFs were used as heterogeneous catalysts for synthesizing EMC by transesterification reaction. The DBU-PO@ZIF-8 composite with phenol as anion has better catalytic activity. Under the appropriate reaction conditions, the yield of EMC can reach 55.7% with high selectivity of 94.7%. The catalytic mechanism of DBU-PO@ZIF-8 in the transesterification reaction was also explored and revealed.
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