SCIENCE OF THE TOTAL ENVIRONMENT
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2021
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IF 7.963
Yuan He,Liangjie Wang,Zhan Chen,Bo Shen,Jinshan Wei,Ping Zeng,Xianghua Wen
Manganese dioxide has been widely recognized as catalyst in catalytic ozonation for organic pollutants removal from wastewater in recent decades. However, few studies focus on the structure-activity relationship of MnO 2 and catalytic ozonation mechanism in water. In the present study, the oxidative reactivity of three different crystal phases of MnO 2 corresponding to α-MnO 2 , β-MnO 2 and γ-MnO 2 towards metoprolol (MET) and ibuprofen (IBU) were evaluated. α-MnO 2 was found to contain the most abundant oxygen vacancy and readily reducible surface adsorbed oxygen (O 2− , O − , OH − ), which facilitated an increase of ozone utilization and the highest catalytic performance with 99% degradation efficiency for IBU and MET. α-MnO 2 was then selected to investigate the optimum key operating parameters with a result of catalyst dosage 0.1 g/L, ozone dosage 1 mg/min and an initial pH 7. The introduction of α-MnO 2 promoted reactive oxygen species (O 2− , O − , OH − ) generation which played significant roles in IBU degradation. Probable degradation pathways of MET and IBU were proposed according to the organic intermediates identified and the reaction sites based on density function theory (DFT) calculations. The present study deepened our understanding on the MnO 2 catalyzed ozonation and provided reference to enhance the process efficiency.
研究领域:
环境科学
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化学工程
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DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
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2019
·Vol. 26
·期 15
·15373-15380
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IF 2.914
Li Yu,Xu Jie,Qian Mengqian,Yu Jie,Pan Jian,Guan Baohong
Alumina has been used as a catalyst for ozonation, surface hydroxyl on which is regarded as the active center for ozone attack, but the influences of hydroxyl generation are still vague. Here, we prepared alumina with different hydroxyl concentrations by adjusting calcination temperatures, of which the catalytic activity was evaluated with the mineralization degree of phenol, and then revealed the active sites of hydroxyl generation with characterization of XRD, Py-IR, and NH 3 -TPD. The results show that the greater the hydroxyl concentration, the higher the catalytic activity, demonstrating that surface hydroxyl contributes to its catalytic activity. The effect of calcination temperatures on hydroxyl concentration and catalytic activity is in accordance with the amount of weak Lewis acid sites on the surface of alumina, illustrating the surface hydroxyl derived from the decomposition of water adsorbed on weak Lewis acid sites. However, the catalytic performance of the alumina decreases slowly in a long-term reaction owing to the active center reduction resulted from the coverage by organic acids from phenol degradation. The present work reveals the influences of hydroxyl generation which are beneficial for adjusting surface hydroxyl regarded as active site for ozone attack and the reason of catalyst deactivation, which provides guideline for the rational design of catalyst.
研究领域:
环境科学
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材料科学
✓ 已验证
DOI
PubMed
高影响因子
CHEMOSPHERE
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2024
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IF 8.1
Xu Yin,Jie Zhang,Siru Chen,Wei Li,Hongwei Zhu,Kajia Wei,Yonghao Zhang,Haoming Chen,Weiqing Han
In this work, an electric field-enhanced heterogeneous catalytic ozonation (EHCO) was systematically investigated using a prepared FeOx/PAC catalyst. The EHCO process exhibited high sulfadiazine (SDZ) and TOC removal efficiency compared with electrocatalysis (EC) and heterogeneous catalytic ozonation (HCO) process. Almost 100% of SDZ was removed within 2 min, and the TOC removal reached approximately 85% within 60 min. Quenching experiments and EPR analysis suggested that the prominent SDZ and TOC removal performance is supported by the enhanced ·OH generation ability. Further study proved that H 2 O 2 formed by O 2 electrochemical reduction, peroxone reaction and electrochemical reduction of ozone contributed to improving ·OH generation. Furthermore, the EHCO system showed satisfactory stability and recyclability compared to conventional HCO systems, and the SDZ and TOC removal rates were maintained at ≥95% and ≥70% in 16 consecutive recycles, respectively. Meanwhile, XPS analysis and Boehm's titration for the FeOx/PAC catalyst used in HCO and EHCO process confirmed that the external electron supply could restrain the oxidation of surface functional groups of PAC and maintain a balance of the Fe(II)/Fe(III) ratio, which proved the critical role of cathode reduction in catalyst in situ regeneration during long consecutive recycles. In addition, the EHCO system could achieve more than 80% SDZ removal within 2 min in different water matrices. These results confirmed that the EHCO process has a wide application perspective for refractory organics removal in actual wastewater.
研究领域:
环境科学
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催化化学
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水处理工程
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产品关联
DOI
PubMed
高影响因子
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
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2024
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IF 6.9
Shupo Liu,Zixiang He,Xiaobin Liao,Xinyue Liu,Menglan Gao,Huayu Zhang,Jing Zou,Zhenming Zhou,Baoling Yuan,Zhimin Yang
Antibiotics and ammonia are generally co-existed in aquaculture tailwater; moreover, ammonia would also be produced from during ozonation, and should be simultaneously removed before discharge or reuse. In this study, catalyst Cu-Co/γ-Al 2 O 3 was screened from a variety of metal oxides and applied in catalytic ozonation of three kinds of antibiotics and NH + 4 -N. Factors that affected their removal, including catalyst dosages, O 3 concentration, initial pH as well as co-existing ions, were investigated. Moreover, the mechanisms were probed by exploring free radicals’ role as well as intermediates identification; and the characteristics of catalysts before and after use were evaluated using SEM, EDS, XRD, XPS, and BET. Results demonstrated that Cu-Co/γ-Al 2 O 3 could significantly stimulate the degradation of the selected antibiotics and NH + 4 -N during ozonation. The degradation efficiencies of ciprofloxacin (CIP), tetracycline (TC), sulfamethoxazole (SMX) and NH + 4 -N can reach up to 95.0 %, 100.0 %, 96.2 %, and 75.7 %, respectively. Plenty of oxygen vacancy (O vs ) and sufficient alkaline sites on the surface of catalyst facilitated the adsorption of pollutants. Furthermore, the transformation of metal ions Cu + /Cu 2+ and Co 2+ /Co 3+ enhanced the electron transfer capacity and favored the formation of reactive oxygen species (ROS) during catalytic ozonation reaction, and their roles in catalytic ozonation has also been verified. The radical quenching experiments demonstrated that ·OH was the main contributor for enhancing pollutants removal. The results of Gaussian calculation coincided with those intermediates detected by UPLC-Q-TOF-MS, the pollutants’ removal mechanisms by catalytic ozonation were proposed basing on them. The overall toxicities were compared for ozone only/catalytic ozonation by zebrafish embryo experiment. The results of this study would provide new a feasible way for treating antibiotics and NH + 4 -N simultaneously in aquaculture wastewater.
研究领域:
环境科学
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水处理技术
✓ 已验证
产品关联
DOI
高影响因子
CHEMOSPHERE
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2018
·
IF 4.427
Xukai Li,Weirui Chen,Yiming Tang,Laisheng Li
Fe-MCM-48 catalyst with a three-dimensional cubic pore structure was directly synthesized via a hydrothermal method, and the mineralization efficiency of diclofenac (DCF) in the catalytic ozonation process (Fe-MCM-48/O 3 ) was assessed. X-ray diffraction (XRD), N 2 adsorption desorption, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) characterizations revealed that Fe existed in the framework of MCM-48, and Fe-MCM-48 possessed a large surface area and a highly ordered cubic mesoporous structure, which could accelerate reactants and products diffusion. Regarding mineralization efficiency, the addition of Fe-MCM-48 significantly improved total organic carbon (TOC) removal, and approximately 49.9% TOC were removed through the Fe-MCM-48/O 3 process at 60 min, which was 2.0 times higher than that in single ozonation. Due to this catalyst's superior structure, Fe-MCM-48 showed the better catalytic activity compared with Fe-MCM-41 and Fe loaded MCM-48 (Fe/MCM-48, Fe existed on the surface of MCM-48). DCF removal in the Fe-MCM-48/O 3 process was primarily based on ozone direct oxidation. The improvement of mineralization efficiency was attributed to the function of generated hydroxyl radicals (•OH), which indicated that the presence of Fe-MCM-48 accelerated ozone decomposition . Moreover, the negatively charged surface of Fe-MCM-48 and the proper pH value of the DCF solution played an essential role in OH generation.
研究领域:
环境科学
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催化材料
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DOI
高影响因子
ACS ES&T Engineering
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2020
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IF 0
Yuxian Wang,Nuo Ren,Jiaxin Xi,Ya Liu,Tao Kong,Chunmao Chen,Yongbing Xie,Xiaoguang Duan,Shaobin Wang
High-performance and robust catalysts act as core drivers for advanced oxidation technologies for decontamination of water resources. In this study, we used a facile strategy to prepare magnetic and N-doped carbon nanotubes with cobalt encapsulation (Co–N@CNTs) to catalyze ozone for decomposition of aqueous organic pollutants. By regulating the thermal conditions during the synthesis, the derived Co–N@CNTs manifested maneuvered adsorption capabilities. The embedded Co nanoparticles (NPs) not only afforded carbon nanotubes with a magnetic property but also significantly boosted catalytic ozonation due to the synergistic coupling of the Co interface and N-doped graphitic layer. Formation of such a coordinating structure accelerated electron transfer at the interface and increased the conductivity of surface carbon to coordinate a redox reaction. Density functional theory (DFT) calculations and experimental evidence confirmed that cobalt coupled with graphene with pyridinic N dopants was the most favorable structure, which remarkably enhanced ozone adsorption and its dissociation to generate reactive oxygen species (ROS). Intriguingly, the catalytic ozonation underwent different nonradical regimes dependent on the molecular structures of target organics. In terms of ROS, surface-adsorbed atomic oxygen (*Oad) was responsible for degradation of oxalic acid, while phenolics were primarily degraded by O3 molecules and singlet oxygen (1O2). This study provides a cost-efficient and recyclable carbocatalyst for wastewater decontamination and new insights into the structure–functional relationships in carbon-based advanced oxidation processes.
研究领域:
环境科学
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材料科学
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产品关联
DOI
ACS Applied Materials & Interfaces
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2018
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IF 8.097
Da Wang,Haodan Xu,Jun Ma,Xiaohui Lu,Jingyao Qi,Shuang Song
Novel single-crystal hexagonal MnTiO3 nanosheets with exposed {0001} facets have been synthesized via a simple one-pot hydrothermal method using NaOH as a mineralizer and tetraethylammonium hydroxide (TEAH) as a morphology controller. The intermediate morphologies of MnTiO3 nanostructures such as nanoparticles, nanowires, nanorods, and nanodiscs are trapped kinetically by adjusting the synthesis conditions. This approach enables us to elucidate the growth mechanisms of MnTiO3 nanosheets based on the tetraethylammonium cation adsorption abilities on different MnTiO3 crystal facets combined with density functional theory calculations. Dissolution and recrystallization processes are involved during the MnTiO3 crystallization. The surface-controlled MnTiO3 has been found to be effective as a catalyst for ozonation in the degradation of 4-chlorophenol (4-CP). Within typical experimental conditions (catalyst dosage = 0.3 g L–1, [4-CP]0 = 50 mg L–1, [O3] = 20 mg L–1, gas flow = 0.1 L min–1, pH 6.8, and T = 293 K), the total organic carbon (TOC) removal efficiency of 4-CP in catalytic ozonation with well-structured MnTiO3 (MnTiO3-180-10 sample) was 76.3% after 60 min, compared with only 22.1 and 38.5% TOC removal in the absence of catalyst and with uncontrolled MnTiO3 (MnTiO3-no TEAH sample), respectively. Benefiting from the high exposure percentage of {0001} facet, mixed-valences of manganese, surface hydroxyl groups, and the enrichment Lewis acid sites provided by Mn and Ti, the morphology-controlled MnTiO3 nanosheets can be applied as heterogeneous catalytic ozonation catalysts which exhibit excellent pollutant degradation. We anticipate that MnTiO3 can be a promising candidate material for the application in remediation of organic pollutants in water.
研究领域:
材料科学
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环境科学
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产品关联
DOI
PubMed
高影响因子
CHEMOSPHERE
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2017
·
IF 4.208
Dan Wu,Xukai Li,Yiming Tang,Ping Lu,Weirui Chen,Xiaoting Xu,Laisheng Li
Zinc oxide (ZnO) nanorods were prepared by a directly pyrolysis method and employed as catalyst for perfluorooctanoic acid (PFOA) degradation. Comparative experiments were conducted to discuss the catalytic activity and flexibility of ZnO. After ZnO addition, the best PFOA degradation efficiency (70.5%) was achieved by ZnO/UV/O 3 system, only 9.5% by sole ozonation and 18.2% by UV 254 light irradiation. PFOA degradation was sensitive with pH value and temperature. The better PFOA removal efficiency was achieved at acidic condition. A novel relationship was found among PFOA degradation efficiency with hydroxyl radicals and photo-generated holes. Hydroxyl radicals generated on the surfaces of ZnO nanorods played dominant roles in PFOA degradation. PFOA degradation was found to follow the photo-Kolbe reaction mechanism. C 2 –C 7 shorter-chain perfluorocarboxylic acids and fluoride ion were detected as main intermediates during PFOA degradation process. Based on the results, a proposal degradation pathway was raised.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Water Process Engineering
·
2022
·
IF 7.34
Lingjie Ke,Jing Liu,Lei Sun,Fei Pan,Xiangjuan Yuan,Dongsheng Xia
In this paper, a series of copper oxide supported manganese dioxide (Cu X Mn T ) composites were prepared by the hydrothermal and deposition precipitation methods. The effects of different hydrothermal temperatures (100 °C–180 °C) and copper doping amounts (1–10 mM) on the structural and physicochemical properties of Cu X Mn T composites were systematically investigated. The BET, SEM , and XRD characterizations revealed that the Cu X Mn T composites exhibited a typical rod-like structure. Besides, with the increscent hydrothermal temperature, the BET specific surface area decreased and the crystal form of the composites changed from α-MnO 2 to β-MnO 2 . The Cu 1 Mn 180 with low specific surface area (3.277 m 2 g −1 ) exhibited the splendid catalytic ozonation activity and the oxalic acid (OA) removal rate reached 87.5% in O 3 /Cu 1 Mn 180 process compared with single ozonation (3.2%). Additionally, it was noteworthy that the excellent catalytic performance of Cu 1 Mn 180 (91.8% of OA removal rate) at pH 3.0 was resulted from the electrostatic adsorption. While, the complexation played a vital role for OA degradation at pH 6.0 and 9.0 with the OA removal efficiencies of 87.5 and 70.3% within 30 min, respectively. Furthermore, Cu 1 Mn 180 could obtain more than 90.9% of OA removal rate during multiple consecutive cycles, representing the satisfactory stability and reusability. Moreover, the multivalent Mn, the structural oxygen species, and Cu species played the key roles for OA degradation in O 3 /Cu 1 Mn 180 process at pH 6.0 via the TEM, ESR, XPS and O 2 -TPD characterizations. Overall, the results presented a promising alternative material for efficient catalytic ozonation application in water.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
WATER RESEARCH
·
2023
·
IF 12.8
Jiakai Qiu,Jing Wang,Mingzhu Ren,Xin Yang,Jianbo Zhang,Xiaolong Zhang,Hongbin Cao,Yongbing Xie
Chloride ion (Cl − ) is one of the most common anions in wastewater and saline wastewater, but its elusive effects on organics degradation are not clear yet in many cases. In this paper, the effect of Cl − on organic compounds degradation is intensively studied in catalytic ozonation of different water matrix. It was found that the effect of Cl − is almost completely reflected by transforming ·OH to reactive chlorine species (RCS), which is simultaneously competitive with organics degradation. The competition between organics and Cl − for ·OH directly determines the ratio of their consumption rate of ·OH, which depends on their concentration and reactivity with ·OH. Especially, the concentration of organics and solution pH may change greatly during organics degradation process, which will correspondingly influence the transformation rate of ·OH to RCS. Therefore, the effect of Cl − on organics degradation is not immutable, and may dynamically change. As the reaction product between Cl − and ·OH, RCS was also expected to affect the degradation of organics. But we found that Cl· had no significant contribution to the degradation of organics in catalytic ozonation, which may due to its reaction with ozone. Catalytic ozonation of a series of benzoic acid (BA) with different substituents in chloride contained wastewater was also investigated, and the results showed that the electron-donating substituents can weaken the inhibition of Cl − on BAs degradation, because they increase the reactivity of organics with ·OH, O 3 and RCS.
研究领域:
环境科学
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废水处理
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2022
·
IF 24.319
Shujuan Zhan,Huating Huang,Chun He,Ya Xiong,Ping Li,Shuanghong Tian
Nitrogen doping sites greatly affected the electronic structure of catalysts. However, identification of nitrogen doping sites in CeO 2 and their effects on catalytic ozonation have never been addressed. Herein, nitrogen was selectively doped at substitutional (N s ) or interstitial sites (N i ) in CeO 2 by simply controlling the heat treatment conditions. The obtained NCe2–400 with 100% N i significantly enhanced the elimination of sulfamethoxazole to 93.7 ± 1.9% within 30 min at the initial solution pH of 6.2. The first-order rate constant reached 8.77 × 10 −2 min −1 , 2.1 and 4.1 times that of 50.1%N s -doped CeO 2 and ozonation, respectively. The experimental and DFT calculation results demonstrate that compared to N s , N i favors the formation of oxygen vacancies (OVs). Both N i and OVs significantly decreased the energy barrier of the adsorption and activation of ozone. This study provides a simple site-tunable N-doping method and gains a new insight into the roles of N i and N s in catalytic ozonation.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Sciences
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2023
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IF 6.9
Zizheng Huangfu,Wei Ju,Yunhan Jia,Ruijun Ren,Zhenbei Wang,Chen Li,Xiaomeng Shang,Yujie Li,Hongnan Liu,Yu Wang,Hao Zheng,Fei Qi,Amir Ikhlaq,Jolanta Kumirska,Ewa Maria Siedlecka
Catalytic ozonation is an effective wastewater purification process. However, the low ozone mass transfer in packed bubble columns leads to low ozone utilization efficiency (OUE), poor organic degradation performance, and high energy consumption. Therefore, there is an urgent need to develop efficient supported catalysts that can enhance mass transfer and performance. However, the reaction mechanism of the support on ozone mass transfer remains unclear, which hinders the development of catalytic ozonation applications. In this study, lava rocks (LR)-supported catalysts, specifically CuMn 2 O 4 @LR and MnO 2 Co 3 O 4 @LR, were proposed for catalytic ozonation of IBP degradation due to their superior catalytic activity, stability, and high OUE. Addition of CuMn 2 O 4 @LR or MnO 2 Co 3 O 4 @LR increased IBP removal efficiency from 85% to 91% or 88%, and reduced energy consumption from 2.86 kWh/m 3 to 2.14 kWh/m 3 or 2.60 kWh/m 3 , respectively. This improvement was attributed to LR-supported catalysts enhancing mass transfer and promoting O 3 decomposition to generate •OH and •O 2 − , leading to IBP degradation. Furthermore, this study investigated the effects of ozone dose, supporter sizes, and catalyst components on ozone-liquid mass transfer. The results revealed that the size of the supporter influenced stacked porosity and consequently affected ozone mass transfer. Larger-sized LR (kLa= 0.172 min −1 ) exhibited better mass transfer compared to smaller-sized supports. Based on these findings, it was concluded that both CuMn 2 O 4 @LR and MnO 2 Co 3 O 4 @LR are potential catalysts for catalytic ozonation in residual IBP degradation of pharmaceutical wastewater, and LR showed good credibility as a catalyst supporter. Understanding the effects of supporters and active components on ozone mass transfer provides a fundamental principle for designing supported catalysts in catalytic ozonation applications.
研究领域:
环境科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）