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486 results on '"Zhao, Yunliang"'

2. Efficient removal of Cd/As combined pollution in water by mechanically activated calcite with FeSO4

Author

MIAO Yanhui, WANG Zhenlei, ZHANG Tingting, ZHAO Yunliang, and WEN Tong

Subjects
water restoration, cd/as combined pollution, coagulating sedimentation, mechanical activation, calcite, Environmental technology. Sanitary engineering, TD1-1066
Abstract

Heavy metal pollution such as cadmium and arsenic in water seriously threatens human health and safety, and the removal of Cd/As combined pollution is more difficult. In this work, the performance of mechanically activated calcite composite FeSO4 to remove Cd/As combined pollution was investigated by Cd/As combined pollution removal test in water. It was found that mechanically activated calcite can significantly improve the removal efficiency of Cd/As combined pollution in water. The results showed that the removal rate of Cd and As can reach 99% in 30 min by activated calcite composite FeSO4. The removal mechanism of Cd/As combined pollution in water by activated calcite and FeSO4 was studied by SEM-EDS, XPS, and XRD. The results showed that the crystallinity and dissolution activity of calcite were changed by mechanical activation, and the hydrolysis of calcite to produce CO32- and OH- was enhanced. OH- promoted the formation of a stable iron oxide bound precipitate of FeSO4 with arsenic, and CO32- binded with cadmium to form a stable precipitate of cadmium carbonate.

Published
2024
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27. Monitoring and Analysis of Eco-Environmental Quality in Daihai Lake Basin from 1985 to 2022 Based on the Remote Sensing Ecological Index.

Author

Ye, Bowen, Sun, Biao, Shi, Xiaohong, Zhao, Yunliang, Guo, Yuying, Pang, Jiaqi, Yao, Weize, Hu, Yaxin, and Zhao, Yunxi

Abstract

Exploring eco-environmental quality dynamics in the Daihai Lake Basin has significant implications for the conservation of ecological environments in the semi-arid and arid regions of northern China. Based on the Google Earth Engine (GEE) platform, the remote sensing ecological index (RSEI) was constructed by coupling Landsat SR remote sensing data from 1985 to 2022. The spatial significance of the RSEI was analyzed using linear regression equations and an F-test. The spatial correlation, distribution characteristics, and driving factors behind the RSEI were explored using Moran's index and a geodetector. The results indicated that (1) the RSEI was appropriate for evaluating eco-environmental quality in the Daihai Lake Basin. (2) From 1985 to 2022, the eco-environmental quality of the Daihai Lake Basin exhibited a positive trend but remained subpar. (3) A positive spatial autocorrelation was demonstrated for eco-environmental quality with increasing spatial aggregation. (4) Significant eco-environmental quality degradation (slope < 0) occurred primarily in Sanyiquan Town in the northeastern region of the basin and in Tiancheng Township in the southeastern region. Conversely, a notable improvement (slope > 0) was predominantly observed in Yongxing and Liusumu in southwestern Daihai. (5) The improvement in the ecological environment of the Daihai Lake Basin was primarily attributed to an increase in NDVI and WET and a decrease in NDBSI and LST. The interaction between NDVI and LST had the greatest explanatory power for the ecological environment. Among the external driving factors, DEM (elevation) was the dominant factor in the RSEI and had the strongest explanatory power. The interaction between DEM and LST was the most significant, and the driving factors were enhanced. This study provided a theoretical basis for the sustainable development of the Daihai Lake Basin, which is crucial for the local ecological environment and economic development. [ABSTRACT FROM AUTHOR]

Published
2024
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35. Reducing secondary organic aerosol formation from gasoline vehicle exhaust

Author

Zhao, Yunliang, Saleh, Rawad, Saliba, Georges, Presto, Albert A, Gordon, Timothy D, Drozd, Greg T, Goldstein, Allen H, Donahue, Neil M, and Robinson, Allen L

Subjects
Climate Action, air pollution, atmospheric particulate matter, gasoline vehicles, secondary organic aerosol, NOx
Abstract

On-road gasoline vehicles are a major source of secondary organic aerosol (SOA) in urban areas. We investigated SOA formation by oxidizing dilute, ambient-level exhaust concentrations from a fleet of on-road gasoline vehicles in a smog chamber. We measured less SOA formation from newer vehicles meeting more stringent emissions standards. This suggests that the natural replacement of older vehicles with newer ones that meet more stringent emissions standards should reduce SOA levels in urban environments. However, SOA production depends on both precursor concentrations (emissions) and atmospheric chemistry (SOA yields). We found a strongly nonlinear relationship between SOA formation and the ratio of nonmethane organic gas to oxides of nitrogen (NOx) (NMOG:NOx), which affects the fate of peroxy radicals. For example, changing the NMOG:NOx from 4 to 10 ppbC/ppbNOx increased the SOA yield from dilute gasoline vehicle exhaust by a factor of 8. We investigated the implications of this relationship for the Los Angeles area. Although organic gas emissions from gasoline vehicles in Los Angeles are expected to fall by almost 80% over the next two decades, we predict no reduction in SOA production from these emissions due to the effects of rising NMOG:NOx on SOA yields. This highlights the importance of integrated emission control policies for NOx and organic gases.

Published
2017

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