Can ultrasound remove pesticide residues?Issuing time:2020-04-05 00:00
Studies have shown that ultrasonic waves can remove pesticide residues in fruits and vegetables. Ultrasound forms cavitation in the aqueous solution and promotes water phase combustion, high temperature decomposition or free radical reaction. The bond energy of OH bonds in water molecules is 119.5kcal/mol. Under the action of ultrasonic waves, Will produce ·OH, which can effectively decompose hard-to-degrade organic pollutants. Mainly under the action of cavitation effect, organic matter proceeds through two processes of high temperature decomposition or free radical reaction. In the local high temperature and high pressure environment generated by ultrasonic cavitation, water is decomposed to produce ·OH radicals, and the air (N2 and O2) dissolved in the solution can also undergo free radical cracking reactions to produce N· and O· free radicals. These free radicals will further trigger the chain scission of organic molecules, the transfer of free radicals and redox reactions: a. Water dissociation: H2O → H·+ HO· H·+ H·→ H2 H·+ O2 → H02· HO2·+ HO2·→ H2O2 + O2 HO·+ HO·→ H2O2 H·+ HO·→ H2O H·+ H2O2 → HO·+ H2O H·+ H2O2 → H2 + HO2· HO·+ H2O2 → HO2·+ H2O HO·+ H2 → H2O + H· b. In the presence of N2: N2 → 2N· N·+ HO·→ NO + H· NO + HO→ HNO2 NO + HO·→ NO2 + H· 2NO2 + H2O → HNO2 + HNO3 N·+ H·→ NH NH + NH → N2 + H2 N·+ O2 → NO + O· c. In the presence of oxygen: O2 → 2O· H·+ O2 → HO·+ O· O·+ H2 → HO·+ H· O·+ HO2 → HO·+ O2 O·+ H2O2 → HO·+ HO2· d. In the presence of organic matter Organic matter + HO→Product Organic matter + H→ product Organic matter + HO2 → product Organic matter + O→Product Organic matter → product |
