Electrically Conductive and Antimicrobial Agro-Food Waste Biochar Functionalized with Zinc Oxide Particles

Zélia Alves; Nuno M Ferreira; Gonçalo Figueiredo; Sónia Mendo; Cláudia Nunes; Paula Ferreira

doi:10.3390/ijms23148022

Electrically Conductive and Antimicrobial Agro-Food Waste Biochar Functionalized with Zinc Oxide Particles

Int J Mol Sci. 2022 Jul 21;23(14):8022. doi: 10.3390/ijms23148022.

Authors

Zélia Alves^{1

2}, Nuno M Ferreira³, Gonçalo Figueiredo⁴, Sónia Mendo⁴, Cláudia Nunes¹, Paula Ferreira¹

Affiliations

¹ Department of Materials and Ceramic Engineering, CICECO-Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal.
² Department of Chemistry, CICECO-Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal.
³ Department of Physics, i3N, University of Aveiro, 3810-193 Aveiro, Portugal.
⁴ Department of Biology, CESAM, University of Aveiro, 3810-193 Aveiro, Portugal.

Abstract

Carbonaceous materials derived from biomass have been used as sustainable platforms for the growth of ZnO particles aiming the production of functional composite fillers. Kidney-bean pods were pyrolyzed by applying an experimental design that demonstrates that the specific surface area (S_BET) of biochar is improved with increasing pyrolysis temperature combined with a short air-oxidation time. Meanwhile, the graphitization degree and the electrical conductivity (EC) of biochars were negatively affected by increasing the air-oxidation time. The biochar sample with the higher EC and the one with the higher S_BET were selected to be functionalized with ZnO particles by a solvothermal methodology, obtaining composites with an EC and S_BET properties superior to the ZnO-rGO composite, in addition to a similar antibacterial activity. The developed ZnO-biochar composite structures, which are more ecological and biocompatible than the ZnO composites derived from graphene sheets, can be applied as electrically conductive and active fillers.

Keywords: carbon material; circular economy; kidney-bean pods; pyrolysis; solvothermal synthesis.

MeSH terms

Anti-Bacterial Agents / chemistry
Anti-Bacterial Agents / pharmacology
Anti-Infective Agents*
Charcoal / chemistry
Electric Conductivity
Food
Refuse Disposal*
Zinc Oxide* / chemistry

Substances

Anti-Bacterial Agents
Anti-Infective Agents
Charcoal
Zinc Oxide

Grants and funding

This work was developed within the scope of the project CICECO-Aveiro Institute of Materials (UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020), CESAM (UIDP/50017/2020 + UIDB/50017/2020) and i3N (UIDB/50025/2020 & UIDP/50025/2020). ZA and PF thank FCT for the grants PD/BD/117457/2016 and IF/00300/2015, respectively. This work was also supported by BIOFOODPACK project (M-ERA.NET2/0019/2016) and by national funds (OE), through FCT–Fundação para a Ciência e a Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of 29 August, changed by Law 57/2017, of 19 July. The NMR spectrometers are part of the National NMR Network (PTNMR) and are partially supported by Infrastructure Project Nr. 022161 (co-financed by FEDER through COMPETE 2020, POCI and PORL and FCT through PIDDAC).