Title: Study on the extraction of fulvic acid from lignite by microwave-assisted hydrogen peroxide

Authors: Ao Zhang; Ying-Jie Zhang; Hong-Lei Zheng; Lu-Lin Ma; Wen-Jing Liu; Guan-Qun Gong

Addresses: Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China; School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China ' Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China; School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China ' Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China; School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China ' Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China; School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China ' Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China; School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China ' Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China; School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China

Abstract: Extraction of fulvic acid (FA) from Hulun Buir (HB) lignite were carried out under the conditions of hydrogen peroxide and microwave-assisted hydrogen peroxide. The results showed that the microwave can greatly improve reaction rate and observably shorten reaction time, while the extraction yield of FA increased around 4%. Purification technology of FA was studied by sulfuric acid-acetone aqueous solution, and then structure of purified FA was evaluated. All results demonstrated that under the assistance of microwave, the oxidative degradation ability of hydrogen peroxide is stronger, the solvent gets higher permeation ability and the oxygen content in FA is higher. Among the oxygenic functional groups of FA, carboxyl group has the highest content, followed by hydroxyl group and the ester content is the lowest. Trisubstituted benzene is the major component in the aromatic structure of FA. In aliphatic structure, content of methylene is the highest. [Received: March 4, 2017; Accepted: October 17, 2017]

Keywords: microwave; hydrogen peroxide; fulvic acid; extraction; lignite.

DOI: 10.1504/IJOGCT.2018.091557

International Journal of Oil, Gas and Coal Technology, 2018 Vol.18 No.1/2, pp.146 - 162

Available online: 26 Apr 2018 *

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