Improving biochar properties by co-pyrolysis of pig manure with bio-invasive weed for use as the soil amendment. (January 2023)

• Record Type: Journal Article
• Authors: Qiu, Jing; Fernandes de Souza, Marcella; Robles-Aguilar, Ana A.; Ghysels, Stef; Ok, Yong Sik; Ronsse, Frederik; Meers, Erik
• Is Part Of: Chemosphere. Volume 312:Part 1(2023)
• Publication Date: 2023-01
• Subjects: Pig manure -- Invasive plant -- Biochar aromaticity -- Metal speciation -- Nutrients; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2022.137229
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Over recent years, pyrolysis has grown into a mature technology with added value for producing soil improvers. Further innovations of this technology lie in developing tailor-made products from specific feedstocks (or mixtures thereof) in combination with adjusted mixing ratio-temperature regimes. In this context, co-pyrolysis of pig manure (PM) and the invasive plant Japanese knotweed (JK) at different mixture ratios (w/w) of 3:1 (P3J1), 1:1 (P1J1), and 1:3 (P1J3) and varying temperatures (400–700 °C) was studied to address the low carbon properties and heavy metals (HMs) risks of manure-derive biochars and beneficially ameliorate the bio-invasion situation by creating value from the plant biomass. Co-pyrolysis of PM with JK increased by nearly 1.5 folds the fixed carbon contents in the combined feedstock biochars obtained at 600 °C compared with PM-derived biochar alone, and all combined feedstock biochars met the requirements for soil improvement and carbon sequestration. The total HMs in PM biochars were significantly reduced by adding JK. The combined feedstock biochar P1J1 generated at 600 °C was the most effective in transforming Cu and Zn into more stable forms, accordingly reducing the associated environmental risk of heavy metal leaching from the biochar. In addition, the accumulation of macronutrients can be an added benefit of the co-pyrolysis process, and P1J1-600 was also the biochar that retained the most nutrients (P, Ca, Mg, and K). Graphical abstract: Image 1 Highlights: Japanese knotweed addition improved the aromaticity of pig manure-derived biochar. Co-pyrolysis reduced total Cu and Zn compared to pig manure-derived biochar. Cu and Zn transformed to stable forms reduce the environmental risk of the biochar. Co-pyrolysis retained higher nutrients than Japanese knotweed-derived biochar alone. A 1:1 ratio of pig manure to Japanese knotweed at 600 °C was the optimal condition.