<p>The contamination and degradation of chlorpyrifos (CP) in soil have become a significant challenge to environmental safety and human health. Biochar can be a sustainable material for immobilizing CP from soil while improving soil quality. Hence, the present study investigated the immobilization of CP by distilled waste (Mentha) derived biochar (BC) in silty-clay (SC) and sandy loam (SL) soils. The study further explores the effect of biochar on the degradation mechanism of CP, enzyme activities, and soil microbial biomass. The CP adsorption by biochar at different concentrations of 5-200 mg L^− 1 was 94–98%, primarily through chemosorption. However, the soil sorption experiment demonstrated the best fit of the Freundlich model. The leaching of CP from soil followed intraparticle diffusion kinetics. A significant reduction in leaching of CP was observed after BC applications in soil. The addition of BC in the soil enhanced the K_d and K_OC values of CP, and this increase was more pronounced in SC. The half-life of CP in biochar treatments (41 to 122 days) was longer than in treatments without biochar (19 to 52 days). The addition of biochar significantly enhanced microbial biomass carbon and enzyme activities in both soils. The resilience of soil enzymes after adding biochar was notably greater in SC than in SL. The study showed that biochar from distilled Mentha waste could immobilize CP in two soil types and enhance soil health.</p> Graphical abstract <p></p>