Persulfate Oxidation Effect of Soil Organic Pollutants by Natural Organic Matters

Abstract

This study explored the degradation effect and mechanism of persulfate oxidation activated by different macromolecular substances (polysaccharides, humic acid, and citric acid), combined with ferrous ions and different kinds of carbohydrate (monosaccharide, disaccharide, and polysaccharide). The results showed that the oxidation effects of total petroleum hydrocarbons (TPHs) and polycyclic aromatic hydrocarbons (PAHs) by different activation treatments were in the order:humic acid combined with ferrous ion > polysaccharide > citric acid chelated with iron > polysaccharide combined with ferrous ion > disaccharides > monosaccharide > CK. Among them, humic acid combined with ferrous ion-activated persulfate achieved the highest removal rates (up to 79.21% and 79.89%, respectively), and also showed the weakest pollutant content rebound phenomenon. For oxidation of high-ring PAHs, humic acid combined with ferrous ion treatment and polysaccharide activation showed great advantages, with degradation rates being 77.96% and 84.37%, much higher than other treatments. Humic acid combined with ferrous ion-activated persulfate result in the highest Eh of soil (up to 618-676 mV), and polysaccharide treatment was secondary, indicating that macromolecular materials exhibited great oxidation ability and can degrade soil organic pollutants efficiently.