Biochar production from waste biomass: Characterization and evaluation for potential applications

In the last years, global focus has been directing towards the circular economy model. In this framework materials that had so far been regarded as waste, are now considered as valuable resources for both energy and added-value materials recovery. In this context, more and more valorization methods and technologies are being developed for waste valorization, with biomass materials of municipal and agroindustrial origin constituting ideal options, due to both composition and availability.

Biochar generation from waste biomass is a method with high potential for effectively valorizing such residual resources, by providing not only a waste management option, but also multiple agronomic and environmental benefits. In fact, biochar materials are characterized by high versatility as far as their applications are concerned. Due to their wide variety of properties, biochars can be used in various applications, such the use as an adsorbent for contaminant removal from water or wastewater, or the use as an amendment for improving soil characteristics and remediating contaminated sites.

In the present study, six different waste biomass feedstocks, specifically three of municipal origin, namely two types of sewage sludge and the organic fraction of municipal solid waste, and three of agroindustrial origin, namely grape pomace, rice husks and exhausted olive pomace, were used to generate biochar through pyrolysis at two different temperatures, i.e. 400 and 600 °C. The resulting carbonaceous materials were then characterized through a series of analyses. Based on both physical and chemical biochar properties, it was able to evaluate their potential use in different applications, for agronomic or environmental purposes.