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

• Published in: International journal of molecular sciences 2022-07, Vol.23 (14), p.8022
• Main Authors: Alves, Zélia, Ferreira, Nuno M., Figueiredo, Gonçalo, Mendo, Sónia, Nunes, Cláudia, Ferreira, Paula
• Format: Article
• Language: English
• Subjects: Agricultural wastes; Air temperature; Antibacterial activity; Antimicrobial agents; Biocompatibility; Biomass; Carbon; carbon material; Carbonaceous materials; Cellulose; Charcoal; circular economy; Composite materials; Composite structures; Design of experiments; Electrical conductivity; Electrical resistivity; Fillers; Food; Graphene; Graphite; Graphitization; kidney-bean pods; Lignin; Metal oxides; Oxidation; Particulate composites; Pyrolysis; solvothermal synthesis; Variance analysis; Vibration; Zinc oxide; Zinc oxides
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms23148022

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 (SBET) 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 SBET were selected to be functionalized with ZnO particles by a solvothermal methodology, obtaining composites with an EC and SBET 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.