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158. Comparison of the catalytic performances of different commercial cobalt oxides for peroxymonosulfate activation during dye degradation

Author

Wang Ying, Teng Yanguo, Xiang Weixu, Zhang Botao, and Zhang Yang

Subjects
Chemistry, Radical, Inorganic chemistry, chemistry.chemical_element, 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, Heterogeneous catalysis, 01 natural sciences, 0104 chemical sciences, Catalysis, chemistry.chemical_compound, Catalytic oxidation, Oxidizing agent, Degradation (geology), 0210 nano-technology, Cobalt, Methylene blue
Abstract

The catalytic performances of different commercial cobalt oxides(Co x O y , i.e., Co2O3, Co3O4, and CoO) for peroxymonosulfate(PMS) activation in dye degradation were compared in this study. The CoO/PMS system exhibited the highest catalytic oxidation performances with more than 96% methylene blue(MB) removal at 90 min. The concentration of dissolved cobalt ions from CoO was 1.474 mg/L at neutral pH and 5.231 mg/L at acidic pH at 90 min which accounted for the high MB removal and CoO activated PMS homogeneously compared to the associated CoSO4/PMS. Co3O4 and Co2O3 exhibited similar catalytic performances and characteristics. The MB removal in Co3O4/PMS and Co2O3/PMS system were more than 88% at neutral pH and over 64% at acidic pH, respectively, in 90 min. The concentration of dissolved cobalt ions from Co3O4 and Co2O3 was less than 0.018 mg/L at neutral pH and 0.036 mg/L at acidic pH at 90 min. The MB removal achieved by Co3O4/PMS and Co2O3/PMS were approximately three times higher than that achieved by their associated CoSO4/PMS systems and the heterogeneous catalysis played a principal role in the processes. According to scavenger experiments, the contributions of the hydroxyl radicals in the MB degradation were negligible compared to sulfate radicals in the CoO/PMS system. Hydroxyl radicals contributed one-third or more and sulfate radicals were the dominant oxidizing species in the Co3O4/PMS and Co2O3/PMS systems. Co x O y could also effectively activate PMS to generate free radicals for degradation of other dyes. The dyedegradation processes in Co3O4/PMS, Co2O3/PMS and CoSO4/PMS systems followed pseudo-first-order kinetic model and dye degradation rates in different systems were also compared.

Published
2017

175. Fast determination of peroxymonosulfate by flow injection chemiluminescence using the Tb(III) ligand in micelle medium.

Author

Tang, Man, Zhang, Bo‐Tao, Teng, Yanguo, Liu, Meilin, and Zhang, Yang

Abstract

Based on the chemiluminescence (CL) phenomenon of peroxymonosulfate (PMS) and Tb(III) enhanced by its ligand in a micelle microenvironment, a fast and sensitive flow injection CL method for PMS detection was proposed and applied to the analysis of different samples and PMS decomposition. Under the optimized conditions, a linear range was obtained from 4.0 × 10–6 mol L–1 to 2.0 × 10–4 mol L–1 with a high correlation coefficient (r = 0.9997), detection limit of 5.0 × 10–7 mol L–1 (S/N = 3) and relative standard deviation of 2.4% for 1.0 × 10–5 mol L–1 PMS (n = 9). This was successfully applied to the determination of PMS in Virkon powder, tap water, and swimming pool water samples with satisfactory recoveries from 94.8% to 104.8%. In particular, the analytical frequency could be as fast as five samples per minute because there was no reaction step before analysis and the CL phenomenon was instantaneous. Therefore, this CL method has also been successfully applied to investigate the PMS decomposition profiles in carbon material (carbon nanotubes, carbon nanofibres, activated carbon and graphene oxide) catalysis systems, which followed pseudo‐first‐order kinetics with good correlation coefficients (r > 0.9305). Quenching experiments and electron spin resonance spectra verified that the CL phenomenon was due to the formation of singlet oxygen, and that hydroxyl and sulfate radicals might be important in the generation of singlet oxygen. Tb(III) is the luminescent emitter according to the characteristics emission bands of the fluorescence and CL spectra in different media. [ABSTRACT FROM AUTHOR]

Published
2020
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189. EVALUATION OF URBANIZED ECOLOGICAL ENVIRONMENT QUALITY: A CASE STUDY ON BEIJING CHAOYANG DISTRICT

Author

Li Yuan, Teng Yanguo, Zhang Haibo, Fang Jiande, Zhang Chen, Li Daiqing, and Lv Shihai

Subjects
Environmental Engineering, Land use, business.industry, Ecological environment, media_common.quotation_subject, Environmental resource management, Analytic hierarchy process, Management, Monitoring, Policy and Law, Pollution, Ecosystem services, Water resources, Geography, Beijing, Ecosystem, Quality (business), business, Environmental planning, media_common
Abstract

The objective of this study is to evaluate the urbanized ecological environment quality with land use classification system (artificial ecological subsystem, water ecological subsystem and continental ecological subsystem). Three land use type ecosystem combined with characteristics of urban ecological environment conditions (space pattern, environment characteristics, biological characteristics, ecosystem service) established the urban ecological environment quality synthetic evaluation index system. Based on the database, this study integrated Delphi, AHP and Integrated Eco-environment Assessment Index Method. The results showed that Beijing Chaoyang district comprehensive urban ecological quality was middle level. Water resources shortage, the total population pressure and urban green spaces shrinkage were negative factors possibly attributable to decrease ecological quality status.

Published
2013

190. Utilization of a Bayesian probabilistic inferential framework for contamination source identification in river environment

Author

Chen Haiyang, Xiaomei Bai, Fansheng Meng, Teng Yanguo, Ruihui Chen, Lijun Jing, and Zhipeng Yao

Subjects
Identification (information), lcsh:TA1-2040, Bayesian probability, Probabilistic logic, Environmental science, Data mining, Contamination, lcsh:Engineering (General). Civil engineering (General), computer.software_genre, computer
Abstract

In the environmental event of hazardous release into river, quick and accurate identification of the contamination source is important for emergence response. Generally, given a noisy and finite set of monitoring information, determining the source items (i.e. location, strength and release time) is an ill-posed inverse problem. In this study, a Markov chain Monte Carlo method combined with advection-dispersion equation (ADE) was proposed for the source identification of contamination event in river system based on a Bayesian probabilistic inferential framework. Case study with analytical solution for one-dimensional ADE showed that the proposed methodology was effective and the mean posterior errors for all source parameters were lower than 3%. Case simulation based on two-dimensional ADE with numerical solution obtained similar results and further demonstrated the utility of the proposed approach for source identification. We hope the study will provide a helpful guidance to develop approach for contamination event source identification to support environmental risk management of river system.

Published
2018

199. Hydrogeochemical Evolution of Interaction Between Surface Water and Groundwater Affected by Exploitation.

Author

Guo, Xueru, Zuo, Rui, Wang, Jinsheng, Meng, Li, Teng, Yanguo, Shi, Rongtao, Gao, Xiang, and Ding, Fei

Subjects
WATER chemistry, RESOURCE exploitation, WATER supply, TOTAL dissolved solids, SPATIO-temporal variation
Abstract

Hydrogeochemical evolution of interactions between surface water and groundwater is crucial for guaranteeing water supply quality in a riverside water source area. This study focuses on the seasonal and spatial characteristics of hydrogeochemical evolution affected by groundwater exploitation in the Hulan water source area using hydrochemical analyses and stable isotope tracers. Results show that the concentrations of major ions and total dissolved solids (TDS) increase considerably during the dry season. A bicarbonate water type is primarily produced by the dissolution of calcite, dolomite and gypsum, as well as the cation exchange and human activities. Along the typical infiltration path, the proportions of surface water increase with proximity to the river from 8%‐63% during the wet season to 11%‐84% during the dry season, which are attributed to an increased hydraulic gradient by exploitation. The typical path is classified into two zones. The first is the intensive mixing zone (within 1 km) with increasing concentrations of major ions and TDS due to mixing effect. The second is the exploitation influence zone (1‐3.3 km) with increased concentrations of Ca2+, Mg2+, SO42−, and HCO3− during the dry season due to two reasons of seasonal variations in evaporation, stronger water‐rock interactions and mixing effects with increased surface water by exploitation. Article impact statement: The hydrogeochemical evolution of surface water‐groundwater interaction is crucial for water supply quality in water source areas. [ABSTRACT FROM AUTHOR]

Published
2019
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200. Review: The projected hydrologic cycle under the scenario of 936 ppm CO2 in 2100.

Author

Hu, Bin, Teng, Yanguo, Zhang, Yilun, and Zhu, Chen

Subjects
GLOBAL warming, HYDROLOGY, EVAPOTRANSPIRATION, GROUNDWATER, MOISTURE
Abstract

A host of environmental consequences will result from global warming, but arguably, the effect on water resources is one of the most consequential. This paper synthesizes results of published modeling studies that examined the groundwater system and hydrologic cycle under the Representative Concentration Pathway (RCP) 8.5 scenario (CO2 at 936-ppm level at year 2100). Natural replenishment of groundwater occurs predominantly from infiltration of precipitation and surface impoundments. Therefore, the first stage of the study was to review a changed hydrologic cycle under RCP 8.5 in terms of influence from (1) precipitation, evapotranspiration, and soil moisture; (2) surface water and its interaction with groundwater; (3) extreme hydrologic events, and (4) teleconnection patterns. The general pattern of climate impact on groundwater resources follows the precipitation pattern with depletion in tropical and/or subtropical regions and with increase in the high-latitude regions of the Northern and Southern Hemispheres. However, regional variability also corresponds to the heterogenous impact of climate changes on regional distribution of precipitation and evapotranspiration, localized interaction between surface water and groundwater, and distances from the oceans with rising sea level. The decline of the water table in many areas may seriously reduce irrigated crop production and adversely impact groundwater-dependent ecosystems. Relatively fewer studies have been conducted on climate-change impacts on groundwater resources compared to surface-water systems, and the uncertainties on the recharge estimates are large. There appears to be an urgent need for including groundwater systems in climate impact assessment and in climate mitigation strategies. [ABSTRACT FROM AUTHOR]

Published
2019
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