Carbon stability and mobility of ball milled lignin- and cellulose-rich biochar colloids

Xueyan Chen; Wenpei Wu; Lu Han; Mingyue Gu; Jing Li; Mengfang Chen

doi:10.1016/j.scitotenv.2021.149759

Carbon stability and mobility of ball milled lignin- and cellulose-rich biochar colloids

Sci Total Environ. 2022 Jan 1:802:149759. doi: 10.1016/j.scitotenv.2021.149759. Epub 2021 Aug 19.

Authors

Xueyan Chen¹, Wenpei Wu², Lu Han³, Mingyue Gu⁴, Jing Li¹, Mengfang Chen⁵

Affiliations

¹ Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
² Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Science, Beijing 100049, China; Jiangsu Engineering Laboratory for Soil and Groundwater Remediation of Contaminated Sites, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
³ Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; Jiangsu Engineering Laboratory for Soil and Groundwater Remediation of Contaminated Sites, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China. Electronic address: hanlu@issas.ac.cn.
⁴ Nanjing Kaiye Environmental Technology Co Ltd, 8 Yuanhua Road, Innovation Building 106, Nanjing University Science Park, Nanjing 210034, China.
⁵ Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; Jiangsu Engineering Laboratory for Soil and Groundwater Remediation of Contaminated Sites, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.

PMID: 34464793
DOI: 10.1016/j.scitotenv.2021.149759

Abstract

Numerous studies have explored the transport mechanism of biochar colloids in porous medium. However, the effect of feedstock biopolymer compositions and pyrolytic temperature on carbon stability and mobility of biochar colloids is limited. This study prepared four ball milled biochar colloids pyrolyzed from lignin-rich pinewoods and cellulose-rich corn stalks under 300 °C and 500 °C (termed as PW300, PW500, CS300, CS500) and analyzed their differences in the chemical stability and transport behaviors. The results indicated that high contents of lignin in biomass and pyrolytic temperature could enhance the compact aromatic structures of biochar colloids characterized by the elemental composition, FTIR, ¹³C NMR and XRD analyses. Therefore, PW500 with the strongest chemical stabilities (least C loss of 13%), electronegativity (-44.9 mV vs. -41.6-28.3 mV) and smallest hydrodynamic diameter (608.7 nm vs. 622-997.2 nm) was obtained under ball milling. Moreover, both the critical coagulation concentrations (CCC) and the maximum relative effluent concentration (C/C₀) with the NaCl ionic strength of 1 mM were demonstrated to be in the increase order of CS300 (76.1 mM, 70%) < PW300 (183.1 mM, 78%) < CS500 (363.9 mM, 89%) < PW500 (563.1 mM, 95%), which suggested stronger colloidal stability and mobility of PW biochar colloids than those of CS biochar colloids. In addition, the C/C₀ for CS300, PW300 and CS500 were about 7.3%-36% lower than that for PW500 with the NaCl ionic strength increasing to 50 mM indicated the notable superiority in the mobility of PW500. These findings can provide new insights toward understanding the transformation and migration, and evaluating the environmental risk of biochar colloids.

Keywords: Biochar colloids; Cellulose; Hydrodynamic diameter; Ionic strength; Lignin.

MeSH terms

Carbon*
Cellulose
Charcoal
Colloids
Lignin*

Substances

Colloids
biochar
Charcoal
Carbon
Cellulose
Lignin