Chemical Modification of Combusted Coal Gangue for U(VI) Adsorption: Towards a Waste Control by Waste Strategy

Yuan Gao, Jiandong Huang, Meng Li, Zhongran Dai, Rongli Jiang and Jixiong Zhang
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Yuan Gao: School of Chemical Engineering and Technology, China University of Mining & Technology, Xuzhou 221116, China
Jiandong Huang: School of Mines, China University of Mining & Technology, Xuzhou 221116, China
Meng Li: School of Mines, China University of Mining & Technology, Xuzhou 221116, China
Zhongran Dai: Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang 421001, China
Rongli Jiang: School of Chemical Engineering and Technology, China University of Mining & Technology, Xuzhou 221116, China
Jixiong Zhang: School of Mines, China University of Mining & Technology, Xuzhou 221116, China

Sustainability, 2021, vol. 13, issue 15, 1-13

Abstract: Uranium mining waste causes serious radiation-related health and environmental problems. This has encouraged efforts toward U(VI) removal with low cost and high efficiency. Typical uranium adsorbents, such as polymers, geopolymers, zeolites, and MOFs, and their associated high costs limit their practical applications. In this regard, this work found that the natural combusted coal gangue (CCG) could be a potential precursor of cheap sorbents to eliminate U(VI). The removal efficiency was modulated by chemical activation under acid and alkaline conditions, obtaining HCG (CCG activated with HCl) and KCG (CCG activated with KOH), respectively. The detailed structural analysis uncovered that those natural mineral substances, including quartz and kaolinite, were the main components in CCG and HCG. One of the key findings was that kalsilite formed in KCG under a mild synthetic condition can conspicuous enhance the affinity towards U(VI). The best equilibrium adsorption capacity with KCG was observed to be 140 mg/g under pH 6 within 120 min, following a pseudo-second-order kinetic model. To understand the improved adsorption performance, an adsorption mechanism was proposed by evaluating the pH of uranyl solutions, adsorbent dosage, as well as contact time. Combining with the structural analysis, this revealed that the uranyl adsorption process was mainly governed by chemisorption. This study gave rise to a utilization approach for CCG to obtain cost-effective adsorbents and paved a novel way towards eliminating uranium by a waste control by waste strategy.

Keywords: combusted coal gangue; chemical modification; uranium; adsorption (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2021
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (2)

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