Utilisation of ultrasonic treatment to improve the soil amelioration property of coal fly ash

Wei Zhou; Xiang Lu; Chongchong Qi; Meng Yang

doi:10.1016/j.jenvman.2020.111311

Utilisation of ultrasonic treatment to improve the soil amelioration property of coal fly ash

J Environ Manage. 2020 Dec 15:276:111311. doi: 10.1016/j.jenvman.2020.111311. Epub 2020 Aug 29.

Authors

Wei Zhou¹, Xiang Lu¹, Chongchong Qi², Meng Yang¹

Affiliations

¹ State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Xuzhou, 221116, China; School of Mines, China University of Mining and Technology, Xuzhou, 221116, China.
² School of Resources and Safety Engineering, Central South University, Changsha, 410083, China; School of Civil, Environmental and Mining Engineering, University of Western Australia, Perth, 6009, Australia. Electronic address: chongchong.qi@csu.edu.cn.

PMID: 32871465
DOI: 10.1016/j.jenvman.2020.111311

Abstract

Environment-friendly disposal of coal fly ash (CFA) is essential for sustainable development and cleaner production of electricity in thermal power plants. Although CFA has been employed for soil amelioration, direct application of CFA to soil may pose risks such as heavy metal contamination. This study investigated recycling of CFA through a novel method, which employs the ultrasonic treatment of CFA before its application. Physico-chemical properties of refuse dump soil and CFA were analysed. Subsequently, the effect of ultrasonic treatment on the physico-chemical properties of CFA was investigated. Different ultrasonic parameters (ultrasonic frequency, time interval, and temperature) were studied using response surface methodology. Finally, plant growth experiments were conducted to verify the feasibility of using ultrasonically treated CFA (UTCFA) for soil amelioration. The results show that untreated CFA cannot be used for soil amelioration due to its unsuitable high pH (10.20) and threatening concentrations of trace elements (6.80 mg/kg for Cadmium and 109.75 mg/kg for Arsenic). Ultrasonic treatment increases the soil amelioration properties of CFA by decreasing pH (to 8.50-9.20), decreasing concentrations of Cadmium and Arsenic (satisfying GB 15618-2018), and improving the water-holding capacity of CFA (reducing water loss). Plant indicators confirm the feasibility of using UTCFA for soil amelioration and suggest that the optimum UTCFA proportion is 20%. This study is a benchmark for the utilisation of ultrasonic treatment to improve the soil amelioration properties of CFA.

Keywords: Coal fly ash; Physico-chemical property; Plant experiment; Recycling; Soil amelioration; Ultrasonic treatment.

MeSH terms

Coal / analysis
Coal Ash* / analysis
Metals, Heavy* / analysis
Soil
Ultrasonics

Substances

Coal
Coal Ash
Metals, Heavy
Soil