Research On Degration Of Phenanthrene In Soil Via Thermally Activated Sodium Persulfate

Phenanthrene(PHE)is a common organic pollutant in soil.Through the research of adsorption characteristics and degration process of PHE in soil at different water bath temperature,this paper reveals the general mechanism of degration of PHE via thermally activated sodium persulfate in soil system.Through the research of soil structure before and after reaction,this paper finds two methods of effectively increasing phenanthrene degradation rate.Through the research of four complex activations,this paper finds the main influences of degration rate.Experimental results show that the degration of PHE is a process of oxidation and adsorption;PHE adsorbed in soil pore structure is difficult to be oxidized;the process of oxidation and adsorption accord with pseudo-first order kinetic equation;The effect of temperature on reaction rate accord with Arrhenius model,the activation energy is 122.6 kJ/mol at 333 K-363 K;The apparent reaction rate constant increases with increase of the dosage of sodium persulfate;The degradation rate of PHE decreases with the increase of initial concentration of PHE,increases with the increase of the water-soil ratio;In the condition of high concentration of sodium persulfate,H+、HCO3-and Cl-have little effect on the degradation rate of PHE,OH-can reduce the degradation rate of PHE.In the condition of 363 K,0.5 mol/L Na2S2O8,100 mg/kgPHE,the degration rate of PHE reachs 65%at 10 min.Thermal activation with other actication combination cannot effectively improve the degration rate of PHE.The main factor of improve degration rate and reaction rate is not the concentration of living radical.The main factors of improve degration rate and reaction rate are the reaction temperature and the contact of PHE and living radical.The soil structure before and after reaction changes a lot.Although high concentration of sodium persulfate and sodium hydroxide can change the soil structure,it cannot wreck the process of PHE adsorpted to soil pore structure.High concentration of sulphuric acid can thoroughly wreck the process of PHE adsorpted to soil pore structure.Surface active agent also can slow down the process of PHE adsorpted to soil pore structure.