ENVIRONMENTAL SCIENCE & TECHNOLOGY
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2019
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IF 7.149
Nan Wang,Hanqing Lv,Yuqi Zhou,Lihua Zhu,Yue Hu,Tetsuro Majima,Heqing Tang
Perfluorooctanoic acid (PFOA) is a persistent organic pollutant that has received concerns worldwide due to its extreme resistance to conventional degradation. A mechanochemical (MC) method was developed for complete degradation of PFOA by using alumina (Al2O3) and potassium persulfate (PS) as comilling agents. After ball milling for 2 h, the MC treatment using Al2O3 or PS caused conversion of PFOA to either 1-H-1-perfluoroheptene or dimers with a defluorination efficiency lower than 20%, but that using both Al2O3 and PS caused degradation of PFOA with a defluorination of 100% and a mineralization of 98%. This method also caused complete defluorination of other C3∼C6 homologues of PFOA. The complete defluorination of PFOA attributes to Al2O3 and PS led to the weakening of the C–F bond in PFOA and the generation of hydroxyl radical (•OH), respectively. During the MC degradation, Al2O3 strongly anchors PFOA through COO––Al coordination and in situ formed from Lewis-base interaction and PS through hydrogen bond. Meanwhile, mechanical effects induce the homolytic cleavage of PS to produce SO4•–, which reacts with OH group of Al2O3 to generate •OH. The degradation of PFOA is initiated by decarboxylation as a result of weakened C–COO– due to Al3+ coordination. The subsequent addition of •OH, elimination of HF, and reaction with water induce the stepwise removal of all carboxyl groups and F atoms as CO2 and F–, respectively. Thus, complete defluorination and mineralization are achieved.
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高影响因子
Journal of Physical Chemistry C
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2019
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IF 4.309
Zenghe Li,Xuejie Chen,Xu Teng,Chao Lu
The formation of hydroxylated intermediates is the first step in the persulfate-based advanced oxidation processes (AOPs) and depends directly on the oxidation degree of recalcitrant pollutants. Therefore, the monitoring of hydroxylated intermediates plays a vital role in persulfate-based AOPs for evaluating the oxidation degree and understanding the degradation mechanism. In this work, based on the attractive amplification of luminol chemiluminescence (CL) signals by hydroxylated intermediates, we developed a rapid, sensitive, and simple CL-based method to monitor hydroxylated intermediate (i.e., 3,5-diethyl-1,4-benzenediol) generated in persulfate-based AOPs of 1,2-divinylbenzene (DVB). The possible mechanism of the proposed CL system was that hydroxylated intermediates could be oxidized by persulfate in alkaline solution to form superoxide anion radicals and thus lead to an increase in the luminol CL. Finally, the proposed CL system was successfully applied in monitoring hydroxylated intermediates generated during persulfate-based AOPs under different degradation conditions, whose validity and reliability were verified by liquid chromatography–mass spectrometry (LC-MS) and Fourier-transform infrared spectroscopy (FT-IR). The generality of the proposed CL system was verified by monitoring hydroxylated intermediates generated in persulfate-based AOPs of methylbenzene and benzoic acid. These results suggested that this present CL system provided a promising indicator for monitoring hydroxylated intermediates in persulfate-based AOPs.
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CHEMICAL ENGINEERING JOURNAL
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2019
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IF 8.355
Yizhen Zhang,Lifen Liu,Qiyuan Chen,Yun He,Michael K.H. Leung
A novel system including peroxymonosulfate (PMS) activation process in a photocatalytic fuel cell (PFC) was established, promoting the degradation efficiency of berberine and enhancing the simultaneous electricity generation. The cathode is based on carbon-fiber cloth (CC) and loaded CoFe 2 O 4 with carbon nano-fibers (CNFs), matching well with Ag NPs/ZnO NRs/NiF photo-anode to drive PFC work. The CNFs/CoFe 2 O 4 /CC cathode is multifunctional, it can activate PMS for sulfate radical ( SO 4 - · ) generation, and can simultaneously accept electrons from photo-anode for transform between Co 3+ and Co 2+ . The adding of PMS in PFC system boosts radical formation and cyclic reactions between related species. This PFC-PMS system showed a high antibiotic degradation efficiency and stable electricity generation (93.5% for berberine degradation, 9.18 h −1 for kinetic rate constant, ~0.50 V for cell-voltage at 2000 Ω). In addition, the pollutant removal capacity, influencing factors and the pollutant degradation mechanism in PFC-PMS system were illustrated. The feasible mechanism of berberine degradation was elucidated by the radical trapping and EPR test and these results confirmed that the formation of reactive species, including SO 4 - · , OH, O 2 - · , 1 O 2 radicals and holes. This study suggests that the established PFC-PMS system is more efficient in wastewater treatment and simultaneous energy recovery.
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Biomaterials Science
·
2019
·Vol. 7
·期 9
·3886-3897
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IF 5.251
Zhengxi Guo,Xiaohong Zhou,Cheng Hou,Zhaoyang Ding,Changchun Wen,Lai-Jun Zhang,Bang-Ping Jiang,Xing-Can Shen
Specific targeting capabilities and effective phototherapeutic functions are the key demands for precise cancer phototherapeutic agents. Herein, a bioinspired nanoplatform composed of Cu(II)-chlorophyll–hyaluronic acid nanoparticles (Cu(II)Chl–HA NPs) was developed for targeting cancer and synergistic photodynamic/photothermal therapy. Inspired by the photonic biosystem of the chloroplast, Cu(II) chlorophyll was used as a photosensitive substituent to covalently connect with a hydrophilic HA tail rather than a natural phytol tail, and this conjugate further assembled into a nanoparticle-like morphology under non-covalent interaction. Time-dependent density functional theory calculations reveal that the Cu(II) chlorophyll has a much smaller energy gap between an excited singlet and excited triplet, and theoretically leads to rapid electron intersystem crossing that would benefit the PDT effect. In addition, a series of experiments have proven that, under 650 nm laser irradiation, the nanoplatform of Cu(II)Chl–HA can produce a high amount of singlet oxygen and exhibit an outstanding photothermal conversion capability. More interestingly, owing to the specific interactions between the HA component and the CD44 receptor on the cell membrane, the HA tails impart Cu(II)Chl–HA NPs an excellent receptor-mediated targeting performance toward CD44-overexpressing cancer cells. Based on these features, the nanoplatform of Cu(II)Chl–HA NPs presents active targeting and outstanding dual modality synergistic PDT/PTT performance of cancer both in vitro and in vivo. Thus, this work opens up a new strategy to fabricate a bioinspired multifunctional cancer phototherapy nanoplatform.
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高影响因子
Environmental Science-Nano
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2019
·Vol. 6
·期 7
·2241-2252
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IF 7.704
Jinxi Feng,Jingxiang Sun,Xiaosheng Liu,Jinzhu Zhu,Ya Xiong,Shuanghong Tian
Two electrocatalysts Pt and RuO2 were directionally co-loaded on the nano-piezomaterial t-BaTiO3 by a two-step process: the alkali deposition–oxidation of RuO2 followed by the selective photo-reduction deposition of Pt. It was found that both Pt and RuO2 could considerably improve the piezo-degradation efficiency of t-BaTiO3 for pollutants. For the biorefractory pesticide tricyclazole, RuO2/t-BaTiO3/Pt possessed a piezo-degradation kinetic constant of 0.032 min−1. The rate constant was 3.11, 2.56 and 2.58 times that of t-BaTiO3, Pt/t-BaTiO3 and RuO2/t-BaTiO3, respectively. Moreover, the rate constant of RuO2/t-BaTiO3/Pt was greater than the sum (0.025 min−1) of the rate constants of two single-loaded materials, Pt/t-BaTiO3 and RuO2/t-BaTiO3. This indicates that co-loaded Pt and RuO2 in RuO2/t-BaTiO3/Pt have a synergistic enhancement effect on the piezo-degradation. By analyzing the kind and amount of the reactive oxygen species (˙OH, 1O2, ˙O2− and H2O2) from these nano-piezocatalytic systems, it was inferred that Pt acted as a cathodic- and anodic-like catalyst while RuO2 acted as an anodic-like catalyst. The mechanism of the synergistic catalysis for co-loaded Pt and RuO2 was similar to the principle of an electrolytic reactor, in which Pt and RuO2 were its two catalytic nano-electrodes and the power was from the piezo-potential of t-BaTiO3.
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CHEMICAL ENGINEERING JOURNAL
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2019
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IF 8.355
Yuwei Pan,Minghua Zhou,Jingju Cai,Yusi Tian,Ying Zhang
Sulfamethazine (SMT) is extensively used as growth promoters and antibacterial drugs. In this study, premagnetized Fe 0 was used to catalyze H 2 O 2 decomposition (pre-Fe 0 /H 2 O 2 ) in the presence of nitrilotriacetic acid (NTA) to remove SMT at neutral pH conditions. In all, 30.3% and 99.8% of SMT were removed by the pre-Fe 0 /H 2 O 2 process (60 min) and the pre-Fe 0 -NTA/H 2 O 2 process (30 min), respectively. The removal rate of SMT in the pre-Fe 0 -NTA/H 2 O 2 process was 2.5 times larger than that in the Fe 0 -NTA/H 2 O 2 process. Electron paramagnetic resonance signals indicated that more radicals were generated in the pre-Fe 0 -NTA/H 2 O 2 system. SMT and NTA and their degradation by-products adsorbed on pre-Fe 0 reduced the contact angle of the particle and prevented the formation of Fe 3 O 4 on the particle surface, thus accelerating Fe 0 corrosion. Tafel scan images confirmed the enhancement of Fe 0 corrosion in the presence of NTA and magnetic field. The Fe 0 corrosion rate (10 9 ) after 20 min of reaction was 6.61 cm/s in pre-Fe 0 -NTA/H 2 O 2 , much higher than that in Fe 0 /H 2 O 2 (0.73 cm/s), pre-Fe 0 /H 2 O 2 (1.47 cm/s) and Fe 0 -NTA/H 2 O 2 (2.94 cm/s). Pre-Fe 0 -NTA/H 2 O 2 could also keep the fast SMT removal with eight consecutive runs without the addition of pre-Fe 0 and NTA and presented high efficiency for SMT removal in real municipal wastewater .
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高影响因子
CHEMOSPHERE
·
2019
·
IF 5.108
Zhendong Li,Dongfang Liu,Yingxin Zhao,Songrong Li,Xiaocheng Wei,Fansheng Meng,Wenli Huang,Zhongfang Lei
In this study, CuO-CeO 2 was synthesized via an easy hydrothermal-calcination method and innovatively applied to peroxymonosulfate (PMS) activation for pollutants degradation under a non-radical oxidation pathway. Singlet oxygen ( 1 O 2 ) was the dominated reactive oxygen species in the CuO-CeO 2 /PMS system, leading to a dramatical degradation efficiency with Rhodamine B (RhB) as model compounds. The observed rate constant of the CuO-CeO 2 /PMS system was 7–11 times higher than that of only PMS , CeO 2 /PMS and CuO/PMS systems. Also, under the reaction conditions of 1.6 mM PMS, 0.4 g/L catalyst and initial pH 7, the degradation efficiencies of RhB, Methylene Blue , Reactive Blue 19 and atrazine were respectively up to 100%, 85.39%, 72.84% and 98.44% in 60 min. X-ray photoelectron microscopy analysis indicated that the electrons transfer between CuO and CeO 2 and the formation of oxygen vacancy in CeO 2 should be responsible for the enhanced 1 O 2 production, which involved a new non-radical oxidation pathway for PMS activation by CuO-CeO 2 catalyst. Moreover, the combination of CuO and CeO 2 increased reusability and stability of catalyst, allowing it remove more than 92% of RhB over a wide pH range (pH = 3–9). This study not only proved that CuO-CeO 2 is an efficient and stable PMS activator but also provided a new insight into PMS activation through a non-radical oxidation pathway for organic contaminants removal from wastewater.
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高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2019
·
IF 14.229
Zhiqun Xie,Jiali Zhou,Jinnan Wang,Corvini Philippe François-Xavier,Thomas Wintgens
Novel Fenton-like catalyst γ-Cu-Al 2 O 3 -Bi 12 O 15 Cl 6 with electron-poor Cu centre and electron-rich Bi centre was synthesized for selective degradation of phenolic compounds. Different from electron-rich Cu centre catalysts, the electron-poor Cu centre, which was induced by high electronegativity of Bi, could facilitate the formation of σ-Cu-ligand with phenolic compounds. On one hand, H 2 O 2 could directly oxidize σ-Cu-ligand to HO-adduct radicals with the generation of OH. Meanwhile, Cu(II) in the σ-Cu(II) complexes could be reduced to Cu(I) by oxidization of the HO-adduct radicals to hydroxylation products. Such reaction not only prevented Cu(II) from oxidizing H 2 O 2 to HO 2 /O 2 − but also enhanced the redox cycle of Cu(II)/Cu(I), which improved the catalytic activity and H 2 O 2 utilization. On the other hand, although the σ-Cu-ligand was gradually decreased with the decrease of phenolic compounds, dual-reaction centre played the dominant role in catalytic reaction . In addition, large amounts of oxygen vacancies (OVs) are formed in Bi 12 O 15 Cl 6 during the calcining process (BiOCl→Bi 12 O 15 Cl 6 ) , which can also increase the generation of OH. Thus, both electron-rich Bi center and OVs could still reduce H 2 O 2 to · OH for organics degradation even without the formation of σ-Cu-ligand. Being attributed to the synergistic effect of σ-Cu-ligand, dual-reaction centre and OVs mentioned above, γ-Cu-Al 2 O 3 -Bi 12 O 15 Cl 6 achieved high catalytic activity for phenolic compounds degradation and utilization efficiency of H 2 O 2 (η). In addition, various analytic methods (XPS, TPR, FT-IR, Raman, EPR and solid-state EPR) were used to prove the synergistic effect of the electron-poor/rich centre, σ-Cu-ligand and OVs of catalyst.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
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2019
·
IF 8.355
Chao Liu,ShanShan Dong,Yinguang Chen
Effective interface contact between components in heterojunction is crucial to realize high photocatalytic performance of photocatalyst. In this paper, the improvement of heterojunction contact by forming new ternary heterostructure via calcining the mixture of tetracycline and melamine to obtain the graphene-like carbon plane grafted g-C 3 N 4 and then coupling it with TiO 2 is reported. The unique carbon plane, which is anchored into g-C 3 N 4 basal domains, acts as a significant role to achieve the sufficient ternary heterojunction contact in the novel carbon plane/g-C 3 N 4 /TiO 2 nanostructure system. Under visible-light irradiation, the new ternary nanocomposite exhibits excellent photocatalytic activity for efficient removal of aqueous organic contaminants: methylene blue (98.6%), tetracycline (94.0%), and norfloxacin (95.3%), with the corresponding degradation rate constants of 0.0441, 0.0302, and 0.0125 min −1 , respectively, which are 54.1, 9.8, and 9.4 times higher than that of the pure g-C 3 N 4 . The mechanism study indicates that the excellent photocatalytic activity is attributed to the effective heterojunction, which can successfully extend visible-light absorption, promote charge separation efficiency, and suppress recombination of the photocatalytic electron-hole pairs. Moreover, the electron spin resonance (ESR) assay and radical scavenger experiments demonstrate that the photogenerated holes (h + ), superoxide anion radicals ( O 2 − ), and hydroxyl radical ( OH) play vital roles in photocatalytic degradation process. Importantly, this work may open up novel insights into the design of ternary heterostructure with highly efficacious photocatalytic performance, which suggests attractive applications in environment protection.
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高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2019
·
IF 14.229
Dahu Ding,Shengjiong Yang,Xiaoyong Qian,Liwei Chen,Tianming Cai
Developing low-cost and efficient metal-free carbon-based catalysts is of great importance but remains a challenge. In this work, rice straw derived biochar was prepared and doped with heteroatoms (N and S) for the catalytic degradation of metolachlor (MET) through activating peroxymonosulfate (PMS). Adsorption process played a critical role for the subsequent degradation process. Surface ketone C (-C = O) was the catalytic active sites for the PMS decomposition. Interestingly, N-doping positively whilst S-doping negatively influenced the MET degradation process. Through experimental investigation and theoretical calculations, N-doping was demonstrated to be beneficial for the interaction between biochar and PMS, thus accelerating the catalytic degradation process. The reactive oxidative species involved in the degradation process were explored by EPR analysis. The degradation pathways were elucidated based on the liquid chromatography time-of-flight mass (LC-TOF-MS) analysis of the degradation products. This study highlights the applications of biochar for the environmental catalysis.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Amina,Xiongyuan Si,Kang Wu,Youbin Si,Balal Yousaf
In this study, fabrication of manganese-incorporated iron oxide-graphene nanocomposite (rGO-FMBO) was reported for the efficient activation of CaO 2 and generation of reactive radicals for the degradation of sulfamethoxazole (SMX). The effects of different systems, catalyst dosage, oxidant dosage, different pH and different reaction time on the degradation of SMX by rGO-APTMS-FMBO/CaO 2 as well as the production of free radicals were also studied. Electron paramagnetic resonance (EPR) technique was used to detect and identify the radical species in this oxidation system and these radicals were further confirmed by scavenging studies with the addition of isopropanol (IPA) and methyl viologen (MV 2+ ). The results indicated that the CaO 2 could be activated by rGO-APTMS-FMBO efficiently for the effective degradation of SMX at neutral pH ( P ≤ 0.01). The mechanism of the activation of CaO 2 by rGO-APTMS-FMBO was that carbon dioxide radicals (CO 2 − ) generated by rGO-APTMS-FMBO could activate the CaO 2 to produce more hydroxyl radicals (HO ), which favored the SMX degradation. EPR studies showed that three types of free radicals HO , CO 2 − , and CH 3 were generated and the radical intensities were much higher in rGO-APTMS-FMBO/CaO 2 system. Both increased pH and reaction time led to the production of more CO 2 − , which activated the CaO 2 to give more HO to degrade SMX. Transformation products/intermediates of SMX were determined and potential mechanism and degradation pathway were proposed. The findings of this study provide new insights into the mechanism of heterogeneous catalysis based on CaO 2 activated by rGO-APTMS-FMBO and the reactivity of this oxidation system toward environmental contaminants.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Tao Pan,Yu Wang,Xin Yang,Xiong-fei Huang,Rong-liang Qiu
Fe(II)-catalyzed peroxymonosulfate (PMS) activation process was able to degrade persistent organic pollutants, such as polybrominated diphenyl ethers (PBDEs), but the slow transformation rate from the generated Fe(III) to Fe(II) restricted the efficiency of this process. In this study, we found that the addition of small quantities of gallic acid (GA), a model compound of natural polyphenols, in the Fe(III)/PMS process (namely GA/Fe(III)/PMS process) could exert a long-term influence on Fe(II) recycle and accelerated the degradation of 2,2′,4,4′-tetrabromodiphenyl ether (BDE47) over 72 h. Under conditions of 20.3 µM GA, 13.6 µM Fe(III) and 400 µM PMS, the degradation efficiency of BDE47 reached 85%, which was 9.4 times higher than that in the Fe(III)/PMS process. The degradation kinetics can be divided into an initial “fast stage” (k obs1 = 0.298 h −1 ) and a second “slow stage” (k obs2 = 0.021 h −1 ). Aromatic radicals such as hydroxycyclohexadienyl radical (poly-HCD ) produced by the attack of SO 4 − /HO on GA was proposed to be responsible for Fe(II) recycle in the first stage, while ring-opened products following SO 4 − /HO attack of GA-quinone mainly initiated Fe(III) reduction in the second stage. Owing to the multiple Fe(III) reduction pathways, PMS would be continuously activated by Fe(II) to form SO 4 − and HO , which were the dominant reactive species for BDE47 degradation. Finally, natural polyphenols extracted from green tea were proven effective in enhancing BDE47 degradation in Fe(III)/PMS process. This study not only provides a new way to propagate Fe(II)-activated persulfate chain reactions for the degradation of refractory organic contaminants, like PBDEs, but also sheds new insight into the reactivity of organic byproducts toward Fe in PMS-based oxidation system.
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