Adsorption of acetone and cyclohexane onto CO2 activated hydrochars

Xueyang Zhang; Wei Xiang; Bing Wang; June Fang; Weixin Zou; Feng He; Yuncong Li; Daniel C W Tsang; Yong Sik Ok; Bin Gao

doi:10.1016/j.chemosphere.2019.125664

Adsorption of acetone and cyclohexane onto CO₂ activated hydrochars

Chemosphere. 2020 Apr:245:125664. doi: 10.1016/j.chemosphere.2019.125664. Epub 2019 Dec 18.

Authors

Xueyang Zhang¹, Wei Xiang², Bing Wang³, June Fang⁴, Weixin Zou⁵, Feng He⁶, Yuncong Li⁷, Daniel C W Tsang⁸, Yong Sik Ok⁹, Bin Gao¹⁰

Affiliations

¹ School of Environmental Engineering, Jiangsu Key Laboratory of Industrial Pollution Control and Resource Reuse, Xuzhou University of Technology, Xuzhou, 221018, PR China; Department of Agricultural and Biological Engineering, University of Florida, Gainesville, FL, 32611, USA; Jiangsu Key Laboratory of Vehicle Emissions Control, Center of Modern Analysis, Nanjing University, Nanjing, 210093, PR China.
² School of Environmental Engineering, Jiangsu Key Laboratory of Industrial Pollution Control and Resource Reuse, Xuzhou University of Technology, Xuzhou, 221018, PR China; Department of Agricultural and Biological Engineering, University of Florida, Gainesville, FL, 32611, USA.
³ State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry Chinese Academy of Sciences, Guiyang, 550081, PR China.
⁴ Department of Agricultural and Biological Engineering, University of Florida, Gainesville, FL, 32611, USA.
⁵ Jiangsu Key Laboratory of Vehicle Emissions Control, Center of Modern Analysis, Nanjing University, Nanjing, 210093, PR China.
⁶ College of Environment, Zhejiang University of Technology, Hangzhou, 310014, China.
⁷ Tropical Research and Education Center, University of Florida, Homestead, FL, 33031, USA.
⁸ Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
⁹ Korea Biochar Research Center & Division of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea.
¹⁰ Department of Agricultural and Biological Engineering, University of Florida, Gainesville, FL, 32611, USA. Electronic address: [email protected].

PMID: 31877458
DOI: 10.1016/j.chemosphere.2019.125664

Abstract

Most of the volatile organic compounds (VOCs) are toxic and harmful to human health and environment. In this study, hydrochars activated with CO₂ were applied to remove VOCs. Two typical VOCs, acetone and cyclohexane, were used as the 'model' adsorbates to evaluate hydrochars' performance. Specific surface areas of pristine hydrochars were small (<8 m²/g), whereas activated hydrochars showed much higher values (up to 1308 m²/g). As a result, the adsorption of VOCs onto the pristine hydrochars (13.24-24.64 mg/g) was lower than that of the activated ones (39.42-121.74 mg/g). The adsorption of the two VOCs onto the hydrochars was exothermal. In addition, there were significant correlations (R² > 0.91) between the VOC removal and hydrochars' specific surface area. These results suggest that the governing mechanism was mainly physical adsorption. Increasing experimental temperature (80-139 °C) desorbed the VOCs from the hydrochars. Due to its higher boiling point, cyclohexane desorption required a higher temperature than acetone desorption. The reusability of the activated hydrochars to the two VOCs was confirmed by five continuous adsorption-desorption cycles. The overall results indicated that hydrochars, particularly after CO₂ activation, are sufficient for VOC abatement.

Keywords: Activated carbon; Air pollution control; Engineered biochar; Green remediation; VOC removal.

MeSH terms

Acetone / chemistry*
Adsorption
Carbon / chemistry*
Carbon Dioxide / chemistry*
Charcoal / chemistry
Cyclohexanes / chemistry*
Environmental Restoration and Remediation / methods
Surface Properties
Temperature
Volatile Organic Compounds / chemistry
Volatile Organic Compounds / isolation & purification*

Substances

Cyclohexanes
Volatile Organic Compounds
Acetone
Carbon Dioxide
Charcoal
Cyclohexane
Carbon