Co-pyrolysis of biomass with magnesium and phosphorus: effect of magnesium content on phosphate release from biochar-based fertilizers.

Autor: Knijnenburg, Jesper T. N., Kasemsiri, Pornnapa, Kaewpradit, Wanwipa, Tarinta, Tanyarat, Jantapa, Wasu, Jeejaila, Thanawan, Saengthip, Chanon, Jetsrisuparb, Kaewta
Zdroj: Biomass Conversion & Biorefinery; Jul2024, Vol. 14 Issue 14, p15351-15361, 11p
Abstrakt: Biochar-based fertilizers prepared through co-pyrolysis of biomass with phosphorus (P) and magnesium (Mg) present an attractive alternative over conventional fertilizers to improve P delivery to crops. Here, sugarcane filter cake was treated with MgO and H3PO4 at different Mg:P ratios (0.5, 1, 1.5, and 2) followed by pyrolysis at 600 °C. The resulting modified biochars were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and total Mg and P. The extractable P was measured in deionized (DI) water and 2% formic acid, and the kinetic phosphate release in DI water was monitored over 240 h. Increasing the Mg:P ratio in the biochar greatly increased the total and extractable P in 2% formic acid but resulted in a lower kinetic phosphate release in DI water. This was explained by a change in P speciation (from crystalline pyrophosphate towards amorphous orthophosphate) and increase in biochar pH with increasing Mg contents. The higher 2% formic acid-extractable P and lower water-soluble P at high Mg:P ratios suggested that the P is potentially highly available to crops while having a reduced risk for P loss to surface waters. Their high pH makes these Mg- and P-rich biochar-based fertilizers potentially attractive for application in acidic soils. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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