Physio-Chemical Characterization of Biochar, Compost and Co-Composted Biochar Derived from Green Waste

Abstract

Organic wastes are naturally biodegradable, but they contribute to environmental pollution and management issues. Composting and pyrolysis are widely used technologies for recycling these wastes into valuable organic products for soil health and crop production. In the current study, fruits vegetables waste (FVW) was converted to biochar, compost, and co-composted biochar. The microcrystal structure, functional groups, surface morphology, and nutrient contents of organic materials were investigated by XRD, FTIR, SEM-EDS, AAS, multi C-N analyzer, and ICP-OES techniques. Heavy metals contamination was not detected in the biomass used for pyrolysis and compost preparation. FVW had an acidic pH (5.92), while biochar, compost, and co-composted biochar had an alkaline pH. Total macronutrient (K, Na, S) and micronutrient (Cu, Fe) concentrations were higher in compost and co-composted biochar, with the exception of K, which was higher in biochar. Biochar had the highest surface area (4.99 m2g), followed by FVW, compost, and co-composted biochar. Co-composted biochar had a porous structure. Si, Ca, and Al contents were common in all organic materials, while P, K, Mg, and S were found with lower concentrations in both biochar and compost. Iron was only found in compost and co-composted biochar. Quartz, sylvite, and calcite were common minerals found in all organic treatments. Biochar contained more aromatic carbon ring structure C=C/C=O and aromatic C-H bending as compared to FVW and compost, thus, making biochar a stable carbon rich material suitable for soil carbon sequestration.

Past, present, and future perspectives of biodegradable films for soil: A 30-year systematic review

“…Javadi et al ( Javadi et al, 2010 ), blended the polyhydroxyalkanoate copolymer poly (3-hydroxybutyrate-co-3-hydroxy valerate) with a biodegradable film by microporous and conventional injection molding, significantly improving its toughness. Biodegradable materials can be combined with organic materials, such as food, vegetable waste, and manure, to generate carbon-rich composts ( Mujtaba et al, 2021 ), which must maintain their physical and mechanical properties at the time of use, but also at the end of use. Composted or biodegraded by microorganisms ( Abu Qdais and Hamoda, 2004 ).…”

Positive Effects of the Combined Application of Compost and Biochar on Metal(loid) Immobilization and Plant Growth Depend on Their Application Quantity

“…While other studies mainly attributed biochar for its role in reducing Pb bioavailability and mobility by sorbing Pb on the surface [40,41]. Other possible reasons behind no significant difference between modalities, even after adding biochar, could be due to the insufficient sorption sites or clogged micropores on biochar surface due to the compost derived materials [42]. Moreover, multiple studies described the mechanisms by which metal(loid)s are immobilized by amendments such as (i) metal adsorption through interactions with oxygenated functional groups present on the surface of biochar, (ii) presence of humic acid contents in the compost, and (iii) precipitation with carbonates and phosphates contained by biochar [35,37,43].…”

The Efficacy of Functional Composts Manufactured Using Spent Coffee Ground, Rice Bran, Biochar, and Functional Microorganisms

“…Biochar can also favor the creation of humic acids over fulvic acids during the composting of the rice bran and can alleviate nitrogen loss in the mature composting products. The addition of biochar during composting reduced the time required to enter the thermophilic phase and helped generate a higher temperature and longer duration in the thermophilic stage [60].…”