Effects of swine manure and straw biochars on fluorine adsorption-desorption in soils

Jiatao Cui; Mengyu Zhang; Meng Mi; Yaming Zhao; Zewen Jin; Ming Hung Wong; Shengdao Shan; Lifeng Ping

doi:10.1371/journal.pone.0302937

Effects of swine manure and straw biochars on fluorine adsorption-desorption in soils

PLoS One. 2024 May 16;19(5):e0302937. doi: 10.1371/journal.pone.0302937. eCollection 2024.

Authors

Jiatao Cui¹, Mengyu Zhang¹, Meng Mi¹, Yaming Zhao¹, Zewen Jin¹, Ming Hung Wong^{1

2}, Shengdao Shan¹, Lifeng Ping¹

Affiliations

¹ Key Laboratory of Recycling and Eco-Treatment of Waste Biomass of Zhejiang Province, Zhejiang University of Science and Technology, Hangzhou, PR China.
² Consortium on Health, Environment, Education, and Research (CHEER), Department of Science and Environmental Studies, The Education University of Hong Kong, Hong Kong SAR, Hong Kong, China.

Abstract

With increasing global awareness of soil health, attention must be paid to fluorine exposure in soils, which poses a threat to human health. Therefore, this study aimed to study the fluorine adsorption characteristics of swine manure and straw biochars and their impact on fluorine adsorption-desorption in soil with batch experiments. The biochar samples originated from high-temperature anaerobic cracking of swine manure (350°C, 500°C, and 650°C) and straw (500°C). Results indicated that the adsorption of soil fluorine reached adsorption equilibrium at around 4 h after the mixing of swine manure and straw biochar. Fluorine adsorption kinetics using these biochars conformed to the quasi-two-stage kinetic model. The fluorine adsorption kinetics for biochar-treated soils conformed to the double-constant equation and the Elovich equation, and the soil treated with straw biochar showed the fastest fluorine adsorption rate. The adsorption isotherms of fluorine for biochars and biochar-treated soils could be fitted by the isothermal adsorption model of Langmuir and Freundlich. The maximal equilibrium quantity of fluorine was 73.66 mg/g for swine manure biochar. The soil, adding with 2% of swine manure biochar achieved with showed at 650°C had the smallest adsorption. This study also shows that the adsorption of fluorine by biochar gradually decreased with the increase of pH. Comparing with other factors, the mixture pH with biochars added had a significant effect on fluorine adsorption. The decreased fluorine adsorption capacities for soils treated with swine manure and straw biochars were closely related to the increased pH in soils after adding biochars. Considering the fluorine threat in soil, this study provides a theoretical basis for the application of biochars on soil fluorine adsorption.

Copyright: © 2024 Cui et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

MeSH terms

Adsorption
Animals
Charcoal* / chemistry
Fluorine* / chemistry
Hydrogen-Ion Concentration
Kinetics
Manure* / analysis
Soil Pollutants / chemistry
Soil* / chemistry
Swine

Substances

biochar

Grants and funding

This work was supported by National Key Research and Development Program of China(2022YFE0196000), Major Projects for Science and Technology Development of Zhejiang Province, China (2019C02061), and Major Projects for Science and Technology Development of Zhejiang Province (2020C01017). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.