Aging impacts of low molecular weight organic acids (LMWOAs) on furfural production residue-derived biochars: Porosity, functional properties, and inorganic minerals

Guocheng Liu; Lei Chen; Zhixiang Jiang; Hao Zheng; Yanhui Dai; Xianxiang Luo; Zhenyu Wang

doi:10.1016/j.scitotenv.2017.07.046

Aging impacts of low molecular weight organic acids (LMWOAs) on furfural production residue-derived biochars: Porosity, functional properties, and inorganic minerals

Sci Total Environ. 2017 Dec 31:607-608:1428-1436. doi: 10.1016/j.scitotenv.2017.07.046. Epub 2017 Jul 21.

Authors

Guocheng Liu¹, Lei Chen¹, Zhixiang Jiang², Hao Zheng³, Yanhui Dai¹, Xianxiang Luo¹, Zhenyu Wang⁴

Affiliations

¹ Institute of Coastal Environmental Pollution Control, Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China.
² College of Environmental Science and Engineering, Qingdao University, Qingdao 266071, China.
³ Institute of Coastal Environmental Pollution Control, Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China. Electronic address: zhenghao2013@ouc.edu.cn.
⁴ Institute of Environmental Processes and Pollution Control, and School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China. Electronic address: wang0628@ouc.edu.cn.

PMID: 28746993
DOI: 10.1016/j.scitotenv.2017.07.046

Abstract

The aging of biochar by low molecular weight organic acids (LMWOAs), which are typical root-derived exudates, is not well understood. Three LMWOAs (ethanoic, malic, and citric acids) were employed to investigate their aging impacts on the biochars from furfural production residues at 300-600°C (BC300-600). The LMWOAs created abundant macropores in BC300, whereas they significantly increased the mesoporosity and surface area of BC600 by 13.5-27.0% and 44.6-61.5%, respectively. After LMWOA aging, the content of C and H of the biochars increased from 51.3-60.2% and 1.87-3.45% to 56.8-69.9% and 2.06-4.45%, respectively, but the O content decreased from 13.8-24.8% to 7.82-19.4% (except BC300). For carbon fraction in the biochars, the LMWOAs barely altered the bulk and surface functional properties during short-term aging. The LMWOAs facilitated the dissolution of minerals (e.g., K₂Mg(PO₃)₄, AlPO₄, and Pb₂P₂O₇) and correspondingly promoted the release of not only plant nutrients (K⁺, Ca²⁺, Mg²⁺, Fe³⁺, PO₄^3-, and SO₄^2-) but also toxic metals (Al³⁺ and Pb²⁺). This research provided systematic insights on the responses of biochar properties to LMWOAs and presented direct evidence for acid activation of inorganic minerals in the biochars by LMWOAs, which could enhance the understanding of environmental behaviors of biochars in rhizosphere soils.

Keywords: Biochar; Functional groups; Inorganic minerals; Low molecular weight organic acids; Porosity.