Study On The Efficiency Of Heterogeneous Fenton Technology For The Treatment Of Gray Water From Ships

With the rapid development of shipping industry,the discharge of ship sewage has become a major pollution source of Marine environment.The oil and surfactant in ship gray water will enter the sewage treatment plant directly without treatment,which will have a negative effect on the efficiency of the treatment plant.Therefore,ship gray water should be treated.Compared with the traditional homogeneous Fenton technology,heterogeneous Fenton technology has the traditional advantages of strong oxidation capacity and no selectivity,and can broaden the range of p H value of the reaction and produce less iron sludge,so it has attracted the attention of experts and scholars domestic and abroad.In this experiment,the heterogeneous Fenton system composed of three catalysts,namely,Fe-carrying zeolite,Fe-carrying iron oxide compound zeolite and Fe-carrying activated carbon,also explored and compared the efficiency of the Fenton system in the treatment of ship gray water.The research contents of this paper include:(1)Three heterogeneous catalysts were prepared by means of high-temperature calcining and impregnation methods,and their adsorption effects on ship gray water were compared,and their kinetic analysis and isotherm fitting were carried out.The adsorption of the three heterogeneous catalysts on ship gray water conforms to the second-order kinetic fitting and the Langmuir equation fitting,in which the saturated adsorption capacities of the iron-carrying activated carbon on kitchen waste gray water,wgraying gray water,grease in mixed gray water and LAS are 41.34mg/L,7.45 mg /L,21.56 mg /L and 5.11 mg /L,respectively.(2)The surface characteristics and surface element contents of the three catalysts before and after loading were compared and analyzed by SEM and EDS.(3)To explore the reaction time,catalyst dosage,p H,temperature,hydrogen peroxide concentration 5 kinds of influence factors on the heterogeneous Fenton technology dealt with the influence of ship’s gray water efficiency,for 20 min,the dosage of catalyst in reaction time,concentration of hydrogen peroxide was 0.10 mol/L and 1g respectively,the p H in the range of 3-6,the temperature is 25℃,the zeolite carrying iron heterogeneous Fenton system biggest oil removal rate of ship gray water.The maximum removal rates of cooking waste gray water,wgraying gray water,grease and Anionic Surfactant in mixed gray water were 95.1%,93.2%,67.2% and 47.8%,respectively.The chemical reaction kinetics of grease and Anionic Surfactant concentration over time was analyzed,and the first-order chemical reaction kinetics was followed.(4)By comparing the adsorption performance,the heterogeneous Fenton oxidation performance and the stability of the heterogeneous catalysts,it can be obtained that the three heterogeneous catalysts all have good adsorption performance,among which the Fe-bearing activated carbon has the best adsorption performance,followed by the Fe-carrying zeolite.However,in the process of heterogeneous Fenton technology,Fenton oxidation performance is better than adsorption performance,which plays a major role.After five experiments,the removal rate of kitchen waste gray water was still above 80% and 75%.In general,two kinds of catalysts,Fe-carrying zeolite and Fe-carrying activated carbon,have the advantages of easy recovery and strong stability and can be widely used.