Abstract: Effects of some factors,like amount of TiO₂ added as the catalyst,initial concentration of carbendazim,thickness of the surface soil on photolysis of carbendazim therein were studied under natural sunlight.Results show that photodegradation of carbendazim fitted the quasi-first-order kinetic equation.The constant of the equation increased from 0.015 8 to 0.045 0 h^-1 with increasing TiO₂ rate from 0 to 200 mg·kg^-1,showing significant linear correlation(r=0.962),and the highest photodegradation rate reached 2.85 times as much as the slowest.The half-life of carbendazim increased with the increasing of soil thickness.

Key words: solar radiation, carbendazim, photodegradation, TiO₂