干旱区生态环境知识资源中心(Arid): Interaction of Ca2+ and soil humic acid characterized by a joint experimental platform of potentiometric titration, UV-visible spectroscopy, and fluorescence spectroscopy

Arid

DOI	10.1007/s11631-021-00453-7
	Interaction of Ca2+ and soil humic acid characterized by a joint experimental platform of potentiometric titration, UV-visible spectroscopy, and fluorescence spectroscopy
	Tang, Haiming; Xiao, Baohua; Xiao, Peiwen
通讯作者	Xiao, BH (corresponding author), Chinese Acad Sci, Inst Geochem, State Key Lab Environm Geochem, Guiyang 550081, Guizhou, Peoples R China.
来源期刊	ACTA GEOCHIMICA
ISSN	2096-0956
EISSN	2365-7499
出版年	2021
卷号	40 期号:3 页码:300-311
英文摘要	Rocky desertification has become a major environmental issue in the karst region of southwestern China. Karst rocky desertification was more severe in regions of limestone soil than in adjacent regions of other soils, despite the relatively higher soil organic matter (SOM) content in limestone soil. The underlying mechanism remains ambiguous. We speculated that the geochemical characteristics of limestone soils in the karst region plays an essential role, especially the high calcium content of limestone soil. To test this hypothesis, we collected limestone soil samples from a limestone soil profile in the southwestern China karst region and extracted humic acid (HA) from these limestone soil samples. We investigated the interaction of Ca2+ and three HA samples on a joint experimental platform, which consists of an automatic potentiometric titrator, a UV-visible spectrometer, and a Fluorescence spectrometer. HA solutions were titrated by Ca2+ and optical spectra of the HA solutions were monitored during the titration experiments. The results indicated that: (1) the interaction of Ca2+ and HA is a combined process of adsorption and complexation. Adsorption dominated the overall distribution behavior of Ca2+, which could be fit by Langmuir and Freundlich isotherm models. Complexation was distinguished only when the concentration of Ca2+ is low; (2) the changes of UV-visible spectroscopy and excitation-emission matrix fluorescence spectroscopy spectra of HA samples when they were binding with Ca2+ implied the apparent molecular size and structure of HA became larger and more complex; (3) the combination of Ca2+ and HA plays an important role in the SOM preservation of limestone soils but the stability of the Ca-HA association was relatively weak. The present study draws attention to maintaining the relatively higher Ca2+ concentration in limestone soils in ecologic restoration attempts in karst regions.
英文关键词	Limestone soil Humic acid Calcium Interaction Titration UV-Vis EEM
类型	Article
语种	英语
收录类别	ESCI
WOS记录号	WOS:000611957700001
WOS类目	Geochemistry & Geophysics
WOS研究方向	Geochemistry & Geophysics
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/352718
作者单位	[Tang, Haiming; Xiao, Baohua; Xiao, Peiwen] Chinese Acad Sci, Inst Geochem, State Key Lab Environm Geochem, Guiyang 550081, Guizhou, Peoples R China; [Tang, Haiming; Xiao, Peiwen] Univ Chinese Acad Sci, Beijing 100049, Peoples R China
推荐引用方式 GB/T 7714	Tang, Haiming,Xiao, Baohua,Xiao, Peiwen. Interaction of Ca2+ and soil humic acid characterized by a joint experimental platform of potentiometric titration, UV-visible spectroscopy, and fluorescence spectroscopy[J],2021,40(3):300-311.
APA	Tang, Haiming,Xiao, Baohua,&Xiao, Peiwen.(2021).Interaction of Ca2+ and soil humic acid characterized by a joint experimental platform of potentiometric titration, UV-visible spectroscopy, and fluorescence spectroscopy.ACTA GEOCHIMICA,40(3),300-311.
MLA	Tang, Haiming,et al."Interaction of Ca2+ and soil humic acid characterized by a joint experimental platform of potentiometric titration, UV-visible spectroscopy, and fluorescence spectroscopy".ACTA GEOCHIMICA 40.3(2021):300-311.