Enhancing Biochar Properties Through Oxidative Pyrolysis: A Spirulina Case Study

Oxidative pyrolysis of spirulina in N2/O2 mixture (11 vol%O2) at 300-600°C enhances bio-oil yield, diminishes heavy organics, and forms oxygen-rich biochar. Elevated temperatures crack oxygen-containing species, yielding fragmented biochar with improved combustion. In-situ IR characterization reveals formation of diverse oxygenated functionalities, impacting biochar’s properties.

March 18, 2024

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Gao, Zhang, et al (2024) Oxidative pyrolysisPyrolysis is a thermochemical process that converts waste biomass into bio-char, bio-oil, and pyro-gas. It offers significant advantages in waste valorization, turning low-value materials into economically valuable resources. Its versatility allows for tailored products based on operational conditions, presenting itself as a cost-effective and efficient More of spirulina: Impacts of oxygen on bio-oil and property of biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More. Journal of Environmental Chemical Engineering. https://doi.org/10.1016/j.jece.2024.112506

In the realm of biomassBiomass is a complex biological organic or non-organic solid product derived from living or recently living organism and available naturally. Various types of wastes such as animal manure, waste paper, sludge and many industrial wastes are also treated as biomass because like natural biomass these More conversion, the incorporation of oxygen into pyrolytic processes has emerged as a promising avenue for enhancing biochar properties and optimizing product yields. Recent research has delved into the intricate mechanisms by which externally added oxygen interacts with volatiles, gases, and biochar, particularly in the context of varied temperatures and oxidative atmospheres.

A study focusing on the oxidative pyrolysis of spirulina, conducted in a N2/O2 mixture at temperatures ranging from 300 to 600°C, offers valuable insights into this phenomenon. Results indicate that the introduction of oxygen facilitates the oxidation of light volatiles and heavy tar, leading to increased bio-oil production while mitigating the formation of heavy π-conjugated organics.

Furthermore, the oxidation of biochar, occurring above 300°C, yields additional oxygen-containing organics, subsequently impacting the material’s properties. At lower temperatures, excessive oxidation results in oxygen-rich biochar, while higher temperatures lead to the cracking of oxygen-containing species, yielding biochar with a fragmented surface.

Characterization via in-situ IR techniques reveals the formation of various functionalities, predominantly -OH, adsorbed CO2, C=O, and C-O-C groups, through the oxidation of aliphatic structures. These additional oxygenated organics contribute to reduced thermal stability but enhanced combustion performance of the biochar, lowering ignition and burnout temperatures.

The study underscores the significance of understanding the role of oxygen in pyrolysis processes, particularly in tailoring biochar properties for diverse applications. Spirulina, chosen for its high protein and nutrient content, serves as an ideal feedstockFeedstock refers to the raw organic material used to produce biochar. This can include a wide range of materials, such as wood chips, agricultural residues, and animal manure. More for investigating the evolution of nitrogen/oxygen-containing functional groups during oxidative pyrolysis.

By elucidating the complex interplay between oxygen, biomass, and biochar, this research paves the way for optimizing pyrolytic processes and harnessing biochar as a versatile platform material for various industrial applications.