Research on the adsorption mechanism of Cu and Zn by biochar under freeze-thaw conditions

Zhen Wang; Tianxiao Li; Dong Liu; Qiang Fu; Renjie Hou; Qinglin Li; Song Cui; Mo Li

doi:10.1016/j.scitotenv.2021.145194

Research on the adsorption mechanism of Cu and Zn by biochar under freeze-thaw conditions

Sci Total Environ. 2021 Jun 20:774:145194. doi: 10.1016/j.scitotenv.2021.145194. Epub 2021 Feb 9.

Authors

Zhen Wang¹, Tianxiao Li¹, Dong Liu², Qiang Fu³, Renjie Hou⁴, Qinglin Li¹, Song Cui¹, Mo Li¹

Affiliations

¹ School of Water Conservancy & Civil Engineering, Northeast Agricultural University, Harbin 150030, China; Key Laboratory of Effective Utilization of Agricultural Water Resources of Ministry of Agriculture, Northeast Agricultural University, Harbin, Heilongjiang 150030, China; Heilongjiang Provincial Key Laboratory of Water Resources and Water Conservancy Engineering in Cold Region, Northeast Agricultural University, Harbin, Heilongjiang 150030, China.
² School of Water Conservancy & Civil Engineering, Northeast Agricultural University, Harbin 150030, China; Key Laboratory of Effective Utilization of Agricultural Water Resources of Ministry of Agriculture, Northeast Agricultural University, Harbin, Heilongjiang 150030, China; Heilongjiang Provincial Key Laboratory of Water Resources and Water Conservancy Engineering in Cold Region, Northeast Agricultural University, Harbin, Heilongjiang 150030, China. Electronic address: liudong9599@yeah.net.
³ School of Water Conservancy & Civil Engineering, Northeast Agricultural University, Harbin 150030, China; Key Laboratory of Effective Utilization of Agricultural Water Resources of Ministry of Agriculture, Northeast Agricultural University, Harbin, Heilongjiang 150030, China; Heilongjiang Provincial Key Laboratory of Water Resources and Water Conservancy Engineering in Cold Region, Northeast Agricultural University, Harbin, Heilongjiang 150030, China. Electronic address: fuqiang0629@126.com.
⁴ School of Environment, Tsinghua University, Beijing 100875, China.

PMID: 33609831
DOI: 10.1016/j.scitotenv.2021.145194

Abstract

To investigate the adsorption mechanism of heavy metals by biochar under freeze-thaw conditions, based on indoor simulation experiments, the changes in pH value, surface area (SA), pore structure and functional groups of biochar under natural and freeze-thaw conditions were analysed. Using isothermal adsorption method, Langmuir and Freundlich adsorption equations of heavy metals, the adsorption characteristics of biochar for heavy metals Cu and Zn were analysed. The results showed that after 10 periods (30 cycles), the pH value of the biochar decreased from 8.80 to 7.99, the SA increased from 6.28 m²/g to 20.26 m²/g, the pore volume (PV) decreased from 0.009 mL/g to 0.003 mL/g, and the pore diameter (PD) decreased from 1.692 to 1.423 nm. In period 10, compared to the control group (CK), the adsorption capacity of Cu and Zn increased by 72.00% and 44.55%, respectively, and the number of oxygen-containing functional groups -OH, -COOH and -C=O greatly increased. This study provides scientific and reasonable theoretical guidance for future studies on the biochar adsorption and biochar remediation of soil.

Keywords: Adsorption mechanism; Biochar; Freeze-thaw cycles; Heavy metals.

MeSH terms

Adsorption
Charcoal*
Metals, Heavy*
Zinc

Substances

Metals, Heavy
biochar
Charcoal
Zinc