Atmosphere
·
2022
·Vol. 13
·期 2
·333
·
IF 3.11
Chao Wang,Lingdong Kong,Shengyan Jin,Lianghai Xia,Jie Tan,Yuwen Wang
Soot and aged soot are often found to be mixed with atmospheric particles, which inevitably affect various atmospheric heterogeneous reactions and secondary aerosol formation. Previous studies have investigated the heterogeneous reaction of NO2with different types of soot, but there are few studies on the heterogeneous reaction of NO2with mixtures containing diesel soot (DS) or aged DS and mineral dust particles. In this study, the effects of DS and aged DS on the heterogeneous reaction of NO2on the surface of γ-Al2O3were investigated via in-situ diffuse reflectance infrared Fourier transform spectrometry (DRIFTS). The results showed that the DS or DS n-hexane extract significantly inhibited the formation of nitrate on γ-Al2O3particles and promoted the formation of nitrite. At 58% RH, with the increase of DS or DS n-hexane extract loading amount, the effect of DS or DS n-hexane extract on the formation of nitrate changed from promotion to inhibition, but DS or DS n-hexane extract always promoted the formation of nitrite. The results also showed that light was conducive to the formation of nitrate on the DS-γ-Al2O3or DS-n-hexane extract-γ-Al2O3particles. Furthermore, the influence of soot aging on the heterogeneous reaction of NO2was investigated under light and no light. In the dark, O3-aged DS-γ-Al2O3or O3-aged DS-n-hexane extract-γ-Al2O3firstly inhibited the formation of nitrate on the mixed particles and then promoted it, while the effect of aged DS on nitrite formation was complex. Under light, the O3-aged DS-γ-Al2O3firstly promoted the formation of nitrate on the mixed particles and then inhibited it, while the O3-aged DS-n-hexane extract-γ-Al2O3promoted the formation of nitrate on the mixed particles. Our results further showed that the production of nitrate on the O3-aged particles under light or no light was greater than that of the UV-nitrate-aged particles. This study is helpful to deeply understand the atmospheric chemical behavior of soot and the heterogeneous conversion of atmospheric NO2.Keywords:soot;NO2;heterogeneous reaction;aged soot;γ-Al2O3
研究领域:
大气化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
ATMOSPHERIC ENVIRONMENT
·
2023
·
IF 5
Xiang He,Aiyilaiti Kudesi,Shuangxi Wang,Xin Liu,Lin Hu
Heterogeneous reactions of toluene/NO 2 with and without O 3 on α-Fe 2 O 3 particles was studied as a function of temperature by using in situ diffuse reflectance infrared Fourier transform spectrometry (DRIFTS). The results show that the formation of R-ONO 2 group is identified on the α-Fe 2 O 3 particles surface, indicating the formation of benzyl nitrate in the presence of toluene/NO 2 with or without O 3 at different temperatures from 253 K to 298 K. From the analysis of the spectral changes, the reaction kinetics, such as reaction rate and uptake coefficient are sensitive to temperature. During the heterogeneous reaction of toluene/NO 2 , the formation rate of organic nitrate increases from (2.38 ± 0.07) × 10 17 ions g −1 s −1 to (5.95 ± 0.09) × 10 17 ions g −1 s −1 when the temperature decreases from 278 K to 253 K. When the trace gases were toluene/NO 2 /O 3 , the reaction rate increases about 3 folds with the increasing of temperature from 253 K to 298 K. In the absence of ozone, nitrification from heterogeneous reaction is exothermic process. However, the addition of ozone dominates the whole reaction process, resulting the different change trends of formation rate at similar range of temperatures. Furthermore, reactive uptake coefficient increases from (6.73 ± 0.02) × 10 −7 to (1.64 ± 0.05) × 10 −6 with decreasing temperature from 278 K to 253 K during the heterogeneous reaction of toluene/NO 2 on α-Fe 2 O 3 particles. The values of activation energy for the heterogeneous reaction of toluene/NO 2 and toluene/NO 2 /O 3 are determined to be −8.60 ± 0.91 kJ mol −1 and 15.14 ± 2.51 kJ mol −1 , respectively. It implies that the heat change is an important factor in affecting the heterogeneous reaction under the seasonal temperature changes.
研究领域:
大气化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 74
·69909-69918
·
IF 3.289
Wentong Song,Shengyang Tao,Yongxian Yu,Xuanlu Du,Shuo Wang
This article reports a facile synthetic approach for preparing magnetic porous catalysts, on which various inorganic compounds are alternately loaded using a pyrogallic acid (PG)-assisted layer-by-layer (LbL) coating. The PG forms an adhesion and reductive layer on the surface of hierarchically porous silica, and Pd, Al2O3, ZrO2, or FeOx can then be introduced on the surface of the material. Compared with the conventional impregnation method, the PG layer obviously improves the dispersion of catalysts and greatly reduces the blocking of the pores, which is caused by the formation of metal oxide catalysts. At the same time, the reduction properties of the layer help to reduce the diameter of the Pd nanoparticles to 5 ± 1.3 nm. The Fe3+ ions are partially reduced into Fe2+ by the PG layer to form Fe3O4, which endows the porous catalysts with a magnetic separation property. The synthesized multicomponent catalysts show excellent catalytic activity for various reactions, including the Suzuki Miyaura coupling, reduction, Knoevenagel condensation and Friedel–Crafts alkylation reactions. The TOF values show an improvement of 2 to 4 times over those of the catalysts prepared by the traditional impregnation method. The multicomponent magnetic catalysts also exhibit superior catalytic performance for many one-pot multistep cascade reactions.
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
Environmental Science-Nano
·
2019
·Vol. 7
·期 1
·327-338
·
IF 7.704
Tao Wang,Yangyang Liu,Yue Deng,Hanyun Cheng,Yang Yang,Kejian Li,Xiaozhong Fang,Liwu Zhang
Atmospheric photochemistry is widely regarded as an important pathway for SO2 oxidation. The influence of irradiation intensity, especially photochemistry under weak sunlight during heavy haze events is not known. This work investigates the irradiation-intensity-dependence of the dust-related heterogeneous process using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and ex situ flow reaction. Illumination of the particles alters the surface oxygen species, and further accelerates the significant oxidation of sulfite species to sulfate products. The sulfate formation rate grows rapidly from the dark state to faint irradiation, while it becomes insensitive to irradiation intensity variation under strong illumination. According to the photo-electrochemical tests and concentration dependence experiments, this interesting phenomenon can be interpreted by the presence of excess SO2 under weak sunlight and sufficient photoinduced active species (PAS) under strong illumination. This uneven promotion effect is beneficial for explaining the sulfate burst under faint sunlight during heavy haze events. More significantly, the uptake of SO2 accounts for the increase of acidic species and the decrease of adsorbed water on the particle surface, thus elevating the particle acidity. Under these circumstances, the dissolution of zinc oxide (ZnO) takes place, and results in diverse principal products varying with the illumination condition, e.g. ZnSO3 under weak sunlight while ZnSO4 under strong irradiation. In general, photochemistry has profound impacts on atmospheric sulfur cycling, as well as the cycle of metal elements. The irradiation intensity dependent effects imply the raising uncertainty in the current air quality models.
研究领域:
环境科学
·
大气化学
✓ 已验证
DOI
高影响因子
ATMOSPHERIC ENVIRONMENT
·
2019
·
IF 4.012
Assiya Zhanzakova,Songying Tong,Kejing Yang,Lu Chen,Kejian Li,Hongbo Fu,Lin Wang,Lingdong Kong
Surfactants are often found to be associated with atmospheric particles . They can change the physicochemical properties of these particles, and thereby impact their chemical reactivity. However, their influences on heterogeneous reactions of atmospheric trace gases have not been paid much attention. In this study, the impacts of different surfactants on the heterogeneous conversion of SO 2 on hematite were investigated by using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), including cationic cetyltrimethylammonium bromide (CTAB), anionic sodium dodecyl sulfate (SDS) and nonionic polyethylene glycol tert-octylphenyl ether (Triton X-100). Results indicated that heterogeneous reactivities of hematite-surfactant mixtures were significantly different due to the presence of different surfactants. Under dry conditions, heterogeneous reactivities decreased with the increase of their concentrations, but the higher reactivities were observed at an appropriate concentration range of CTAB and SDS when compared to pure hematite, showing their promoting effects at this concentration range. Under the condition of 58% relative humidity, the heterogeneous reactivities increased first and then decreased with the increasing mass fractions of CTAB and SDS, but pure hematite showed the highest reactivity. While the mixtures containing Triton X-100 had stronger ability to suppress sulfate formation under 58% RH than under dry condition, though these mixtures under 58% RH presented same trend as under dry condition. Water molecules can renew surface reactive sites and promote sulfate formation at an appropriate mass fraction of CTAB or SDS, water molecules can also promote the adsorption mode transition of Triton X-100 from adsorption through terminal OH groups to adsorption through ethoxyl groups, resulting in more surface active sites being covered and a drastically decrease in the reactivity. A possible mechanism for the impact of surfactants on the heterogeneous conversion of SO 2 on hematite is proposed, and atmospheric implications based on these results are discussed.
研究领域:
大气化学
·
环境科学
✓ 已验证
DOI
高影响因子
Journal of Cleaner Production
·
2022
·
IF 11.072
Shuo Wang,Xiaoling Huang,Luowei Pei,Xinyi Zhu,Songming Zhu,Ying Liu,Zhangying Ye
UV photo-electrocatalytic process has emerged as a promising approach for the abatement of ammonia nitrogen in wastewater. However, the radical chemistry for ammonia nitrogen removal in this process requires further clarification. The heterogeneous reaction pathways and mechanism of ammonia nitrogen oxidation in the UV photo-electrocatalytic process were investigated in this study. Photocurrents of the Ti/RuO 2 -IrO 2 -TiO 2 electrodes with good electrocatalytic behavior were enhanced by UV radiation. Compared with the electrocatalytic process, the removal rates of ammonia nitrogen were improved by 12.4%∼20% at the Cl − concentration of 50 mM in the photo-electrocatalytic process. The ammonia nitrogen was mainly transferred into N 2 , meanwhile, the formation of nitrogenous by-products, active chlorine, and chloramines was inhibited in the photo-electrocatalytic process. The contribution of UV radiation was to photo-decompose the active chlorine and chloramines, generating free radicals. The removal efficiency of ammonia nitrogen reached more than 64% after the elimination of free radicals. The electro-generated HOCl was the principal species for ammonia nitrogen removal, and the synergistic effect for the acceleration of ammonia nitrogen oxidation resulted from the photo-generated chlorine radicals. This investigation provides insight into the electrochemistry , photochemistry , and radical chemistry for the heterogeneous catalytic degradation of ammonia nitrogen by UV photo-electrocatalytic process.
研究领域:
环境科学
·
电化学
·
光化学
✓ 已验证
DOI
高影响因子
Environmental Science-Nano
·
2018
·Vol. 5
·期 8
·1821-1833
·
IF 6.087
Tao Wang,Yangyang Liu,Yue Deng,Hongbo Fu,Liwu Zhang,Jianmin Chen
Sulfate compounds formed on mineral dust nanoparticles contribute significantly to severe haze events. Atmospheric particles are complex mixtures that comprise various species and little is known about the heterogeneous conversion of sulfur dioxide (SO2) on multi-composition nanoparticles. In this study, the heterogeneous reaction of SO2 on hematite–alumina mixtures is investigated using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Reactions in the presence of SO2 (polluted period) and its subsequent absence (clean period) are included. It is found that sulfite and sulfate species are the dominant products on alumina and hematite-containing mixtures, respectively. Since the uptake coefficients calculated using both Brunauer–Emmett–Teller (BET) surface area and geometric surface area present similar ‘S’ shape uptrends with increasing hematite proportion, a logistic regression model is employed for further predictions. Sulfate formation still occurs during the clean period, which can be attributed to the physical adsorption of SO2 during the polluted period. In both the periods, hematite-rich mixtures exhibit higher sulfate yields compared to their corresponding theoretical values based on the contribution of each individual component, whereas alumina-rich mixtures present an opposite trend, implying synergistic and antagonistic effects, respectively. A simplified mechanism is demonstrated and the environmental implications are discussed.
研究领域:
大气化学
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环境科学
·
纳米材料化学
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表面反应动力学
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气溶胶科学
✓ 已验证
DOI
高影响因子
ATMOSPHERIC ENVIRONMENT
·
2022
·
IF 5.755
Yangyang Liu,Tao Wang,Qiuyue Ge,Zhuocheng Shi,Kejian Li,Kedong Gong,Lifang Xie,Wei Wang,Qianlong Wang,Jin Han,Hongbo Fu,Jianmin Chen,Liwu Zhang
Flow velocity, potentially linked to dry deposition velocity and wind speed parameters, show non-marginal significance in the heterogeneous oxidation of SO 2 on α-Fe 2 O 3 particles. Our uptake measurement results produce lab-based evidence that an increase in flow velocity can potentially strengthen SO 2 uptake capability over α-Fe 2 O 3 by nearly one order of magnitude within the range of considered reaction conditions. Additionally, specimen analysis of surface S-containing products indicates a distinct SO 2 oxidation regime, shifting from the heterogeneous reaction mediated by active sites under low flow velocity and low RH to an aqueous-like multiphase-dominated pathway under high flow velocity and high RH. An attempt was further made to link this experimental parameter to dry deposition velocity regulated by wind force in the atmosphere. This work highlights the significance of flow velocity in triggering fast sulfate production concerning dust chemistry.
研究领域:
环境科学
·
大气化学
✓ 已验证
产品关联
DOI
高影响因子
Environmental Science-Nano
·
2021
·Vol. 8
·期 3
·698-710
·
IF 8.131
Kejian Li,Xiaozhong Fang,Tao Wang,Kedong Gong,Muhammad Ali Tahir,Wei Wang,Jin Han,Hanyun Cheng,Guanjun Xu,Liwu Zhang
Water-soluble low-molecular-weight dicarboxylic acids (DCAs) and corresponding salts are ubiquitous in the atmosphere. They could efficiently form chelates with iron in atmospheric particles, which could be photoexcited to generate a series of strong oxidants, and have profound impacts on atmospheric chemistry. However, the influences of iron–DCAs complexes on the heterogeneous uptake of atmospheric trace gases are unclear. In this study, the effects of dominant dicarboxylic acid salts (including oxalate, malonate, and succinate) on the heterogeneous SO2 conversion with hematite nanoparticles were systematically investigated using film flow reaction and in situ DRIFTs experiments. It was found that a trace amount of DCA salts could significantly accelerate sulfate formation under solar light illumination. Additionally, similar results were also observed on the Arizona test dust, a proxy of authentic mineral dusts. Moreover, the iron solubility was increased owing to the effects of oxalate complexation, especially under light irradiation. Furthermore, the reaction mechanisms for the enhanced SO2 uptake and iron dissolution in the presence of DCA salts were proposed, and atmospheric environmental implications were discussed.
研究领域:
环境科学
·
大气化学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Yanhong Li,Qifeng Zhang,Yi Lu,Zhiting Song,Changjiang Wang,Dongshuo Li,Xiao Tang,Xianju Zhou
The photocatalytic degradation of tetracycline in aqueous solution is a typical heterogeneous reaction, and thus the design of efficient photocatalysts for tetracycline degradation should revolve the process features of heterogeneous reaction closely. In the present work, TiO 2 -P/ g -C 3 N 4 composites with abundant surface hydroxyls were prepared by coupled g -C 3 N 4 nanosheets with plasma treated TiO 2 (TiO 2 -P) nanoparticles . The resultant TiO 2 -P/ g -C 3 N 4 as photocatalysts showed higher activity for the degradation of tetracycline in aqueous solution than g -C 3 N 4 , TiO 2 , TiO 2 -P and TiO 2 / g -C 3 N 4 under visible light irradiation. The better activity of TiO 2 -P/ g -C 3 N 4 photocatalysts for tetracycline degradation could be ascribed to the good synergy between TiO 2 -P and g -C 3 N 4 . Specifically, due to the presence of surface hydroxyls on TiO 2 -P, the tetracycline adsorption activity, electrons-holes separation property as well as H 2 O 2 activating activity of TiO 2 -P/ g -C 3 N 4 during tetracycline degradation were improved. By integrating the property of g-C 3 N 4 photocatalyst in H 2 O 2 production, as well as the property of TiO 2 -P in activating H 2 O 2 into •OH and •O 2 - , efficient photo-Fenton degradation of tetracycline was achieved in the TiO 2 -P/ g -C 3 N 4 photocatalytic system. Our study on TiO 2 / g -C 3 N 4 composite photocatalyst provides helpful inspiration to design photocatalysts with high-activity for the photo-Fenton degradation of organic pollutants .
研究领域:
环境催化
·
材料化学
·
环境污染治理
·
光化学
·
纳米材料
✓ 已验证
DOI
高影响因子
Journal of Environmental Sciences
·
2022
·
IF 6.796
Lanxiadi Chen,Chao Peng,Jingchuan Chen,Jie Chen,Wenjun Gu,Xiaohong Jia,Zhijun Wu,Qiyuan Wang,Mingjin Tang
Mineral dust is an important type of ice nucleating particles in the troposphere; however, the effects of heterogeneous reactions on ice nucleation (IN) activities of mineral dust remain to be elucidated. A droplet-freezing apparatus (Guangzhou Institute of Geochemistry Ice Nucleation Apparatus, GIGINA) was developed in this work to measure IN activities of atmospheric particles in the immersion freezing mode, and its performance was validated by a series of experimental characterizations. This apparatus was then employed to measure IN activities of feldspar and Arizona Test Dust (ATD) particles before and after heterogeneous reaction with NO 2 (10±0.5 ppmv) at 40% relative humidity. The surface coverage of nitrate, θ (NO 3 − ), increased to 3.1±0.2 for feldspar after reaction with NO 2 for 6 hr, and meanwhile the active site density per unit surface area ( n s ) at -20°C was reduced from 92±5 to <1.0 cm −2 by about two orders of magnitude; however, no changes in nitrate content or IN activities were observed for further increase in reaction time (up to 24 hr). Both nitrate content and IN activities changed continuously with reaction time (up to 24 hr) for ATD particles; after reaction with NO 2 for 24 hr, θ (NO 3 − ) increased to 1.4±0.1 and n s at -20°C was reduced from 20±4 to 9.7±1.9 cm −2 by a factor of ∼2. Our work suggests that heterogeneous reaction with NO 2 , an abundant reactive nitrogen species in the troposphere, may significantly reduce IN activities of mineral dust in the immersion freezing mode.
研究领域:
大气科学
·
环境化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2024
·
IF 10.8
Lifang Zhang,Wenting Yuan,Wangchao Zhao,Bo Yang,Xiaoqiao Jiao,Li Zhou,Shiqian Long,Jiwen Xu,Weilin Huang,Chenglin Liu,Guomao Zheng,Huizhong Shen,Jianhuai Ye,Lei Zhu,Tzung-May Fu,Xin Yang,Chen Wang
Carcinogenic nitrosamines have been widely studied due to their risk to human health. However, the universality and evolutionary processes of their generation, particularly concerning their secondary sources, remain unclear at present. We demonstrated through laboratory flow tube experiments that corresponding nitrosamines were generated from heterogeneous reactions of nitrous acid (HONO) with five structurally diverse amines commonly found indoors, including diphenylamine (DPhA), dibenzylamine (DBzA), dioctylamine (DOtA), N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD), and N-phenyl-1-naphthylamine (PANA). The heterogeneous reaction rate constants of DBzA and DOtA with HONO (∼70 ppb) were 1.21 × 10–3 and 2.13 × 10–3 min–1 at 30% relative humidity (RH), resulting in a lifetime of 13.8 and 7.8 h. As compared to higher RH (∼80%), more nitrosamines were produced from the reaction of HONO with surface-sorbed DBzA, DOtA, 6PPD, and PANA at lower RH (30%), with product yields ranging from <0.1% to 0.5%. Furthermore, we observed the formation of nitroso-6PPDs and nitro-6PPDs during room air exposure of 6PPD in a genuine indoor environment, in addition to various other transformation products indicative of reactions of 6PPD with HONO, NOx, and ozone indoors. This study confirmed the universality of the heterogeneous reaction of surface-sorbed amine with HONO as a source of nitrosamines indoors.
研究领域:
环境化学
·
室内空气质量
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大气科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）