Volatile Organic Compounds Adsorption Capacities of Zeolite/Activated Carbon Composites Formed by Electrostatic Self-Assembly

Dingcheng Liang; Fengqin Yu; Qiang Xie; Qingping Chen; Yuan Liu; Yuhua Zheng; Keping Zhu; Zhijun Zhang; Jun Liu; Xiao Zhu; Jinchang Liu; Zihan Zhu

doi:10.1021/acsami.3c06686

Volatile Organic Compounds Adsorption Capacities of Zeolite/Activated Carbon Composites Formed by Electrostatic Self-Assembly

ACS Appl Mater Interfaces. 2023 Aug 16;15(32):38781-38794. doi: 10.1021/acsami.3c06686. Epub 2023 Aug 4.

Authors

Dingcheng Liang¹, Fengqin Yu¹, Qiang Xie¹, Qingping Chen¹, Yuan Liu¹, Yuhua Zheng², Keping Zhu³, Zhijun Zhang¹, Jun Liu⁴, Xiao Zhu⁵, Jinchang Liu¹, Zihan Zhu¹

Affiliations

¹ School of Chemical and Environmental Engineering, China University of Mining and Technology-Beijing, Beijing 100083, P. R. China.
² State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, P. R. China.
³ Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, Beijing Key Laboratory of Bioinspired Energy Materials and Devices, School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, P. R. China.
⁴ College of Chemistry, Taiyuan University of Technology, Taiyuan 030024, Shanxi, P. R. China.
⁵ State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, P. R. China.

PMID: 37540050
DOI: 10.1021/acsami.3c06686

Abstract

Activated carbon (AC) is a broad-spectrum adsorbent but is flammable and has low adsorption capacities for polar and/or high-boiling volatile organic compounds (VOCs), while zeolites exhibit high thermal stability but poor adsorption of macromolecular and nonpolar VOCs. In this study, zeolite/AC composites were synthesized with the aim of obtaining broad-spectrum, efficient, and safe adsorbents for VOCs. Dimethyldiallylammonium chloride (DDA)-modified AC was used as a carrier for an in situ hydrothermal reaction enabling assembly with zeolites due to electrostatic attraction. Interface models were constructed for their phases, which revealed the binding force and simulated the binding process. The adsorption and flame resistance of the composites were evaluated. The results showed that DDA effectively modified AC to give it a long-lasting positive charge in solutions. High-silicon and pure-silicon zeolites exhibited low negative charges or were even neutral; it was difficult to combine with the modified AC via electrostatic attractions. Instead, LTA zeolites with high aluminum contents and negative charges were used, and the seed-induction method was used. Ethanol and ultrasonic dispersion were used to prevent agglomeration of the seeds and modified AC powder, so they were self-assembled electrostatically. Moreover, the crystallization time was extended and composites with high zeolite loadings were successfully prepared. According to the model calculation, the binding energy between the zeolite and AC before and after the DDA modification were 324.97 and 1076.46 kcal mol^-1, respectively, and the distance between them was shortened by 2.7 Å after DDA treatment. As a result, AC and zeolite combined more closely and exhibited a stronger binding energy. The adsorption capacity for highly polar dichloromethane was improved by zeolite loading on the AC, and the bed penetration time was doubled. However, impregnation with inorganic sodium enhanced the reactivities of the organic components in the composite, and the ignition point was slightly reduced. Furthermore, the electrostatic self-assembly method can expand to prepare the LTA zeolite/columnar AC composite from shaped AC, greatly improving its application prospects.

Keywords: activated carbon; adsorption; composites; interface model; volatile organic compounds; zeolite.