Reducing acetochlor toxicity through subcritical hydrolysis technology: Investigating the hydrolysis mechanism

The primary objective of this investigation was to mitigate the toxicity of acetochlor (ACT) through subcritical hydrolysis treatment and to evaluate the effectiveness of this method in reducing the associated environmental risks. To achieve this, gas chromatography-time-of-flight mass spectrometry (GC×GC-TOFMS), Fourier transform infrared spectrometry (FT-IR), and scanning electron microscopy (SEM) were utilized to characterize the distribution patterns, functional group variations, and morphological changes in the hydrolyzed derivatives of ACT. The GC×GC-TOFMS analysis identified 39 hydrolytic by-products, primarily aromatic, aliphatic, and aliphatic heterocyclic compounds. Among these, four distinct aliphatic compounds were classified as either fatty esters or fatty amines. The subcritical hydrolysis experiments demonstrated that the highest hydrolysis yield of ACT, approaching complete decomposition, was achieved at a hydrothermal temperature of 280 °C with a reaction time of 60 minutes. Furthermore, SEM analysis revealed that as the hydrolysis temperature increased, the hydrochar surface became rougher, with a significant increase in pore structures, and the surface of the ACT sample exhibited a melting flow state. The study also explored and discussed the detailed pathways of hydrolytic transformation of ACT under subcritical hydrolysis conditions. • A new technology based on subcritical hydrolysis for the hydrolysis of acetochlor is proposed. • A novel pathway elucidating the hydrolytic transformation of acetochlor has been unveiled. • The issue of environmental hazards posed by acetochlor and its toxic by-products has been successfully addressed. • FT-IR analysis unveiled the dynamic evolution of functional groups.