Non-thermal plasma enhances performances of biochar in wastewater treatment and energy storage applications

Abstract

Surface functionalization or modification to introduce more oxygen-containing functional groups to biochar is an effective strategy for tuning the physicochemical properties and promoting follow-up applications. In this study, non-thermal plasma was applied for biochar surface carving before being used in contaminant removal and energy storage applications. The results showed that even a low dose of plasma exposure could introduce a high number density of oxygen-functional groups and enhance the hydrophilicity and metal affinity of the pristine biochar. The plasma-treated biochar enabled a faster metal-adsorption rate and a 40% higher maximum adsorption capacity of heavy metal ion Pb²⁺. Moreover, to add more functionality to biochar surface, biochar with and without plasma pre-treatment was activated by KOH at a temperature of 800 °C. Using the same amount of KOH, the plasma treatment resulted in an activated carbon product with the larger BET surface area and pore volume. The performance of the treated activated carbon as a supercapacitor electrode was also substantially improved by>30%. This study may provide guidelines for enhancing the surface functionality and application performances of biochar using non-thermal-based techniques.

Key words： non-thermal plasma; surface functionalization; biochar modification; wastewater treatment; supercapacitor

Acknowledgments

This work was supported by the National Natural Science Foundation of China (Grant No. 52007023), the Natural Science Foundation of Liaoning Province, China (Grant Nos. 2020-BS-073, 2019-ZD-0160), the China Postdoctoral Science Foundation (Grant No. 2019M661107), the Dalian Maritime University basic scientific research business expenses key scientific research cultivation project (Grant No. 3132020371) and the Fundamental Research Funds for the Central Universities (Grant No. 3132021159). Rusen Zhou thanks the financial support from QUT Postgraduate Research Award and Faculty Write Up Scholarship. Kostya (Ken) Ostrikov thanks the Australian Research Council (ARC) and QUT Centre for Materials Science for partial support.

Electronic Supplementary Material

Supplementary material is available in the online version of this article at https://dx.doi.org/10.1007/s11705-021-2070-x and is accessible for authorized users.

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