Alkaline-thermal synergistic activation of persulfate for sawdust hour-level humification to prepare fulvic-like-acid...

Sawdust is a by-product of wood processing and it was rapidly humified with K₂S₂O₈ under alkaline-thermal synergistic activation to produce a fulvic-like-acid (FLA) organic fertilizer (SFOF) in this study. The optimum conditions were K₂S₂O₈: KOH mass ratio of 1:2 and 150°C, meanwhile FLA yield could reach 180.3 mg/g in 2 h. The carboxylation, Maillard reaction, and aromatization processes occurred during sawdust humification. And then, SFOF was mixed with attapulgite and modified starch binder to get an organic fertilizer (SAM), and coated with amino silicone oil (ASO) to create a slow-release granule (SAM@ASO). The release mechanism of FLA from SAM@ASO was consistent with Ritger-Peppas release kinetics. SAM@ASO, with high biosafety, could promote water spinach growth and remediate acidic soil (pH from 4.9 to 6.3). This method offers a promising approach for sawdust utilization and a novel FLA-based organic fertilizer for acidic soil remediation.