Performance Study Of Flocculation-Magnetic Separation Technology For Wastewater Treatment

With the rapid development of national economy and chemical industry,environmentpollution has been becoming more and more serious.Chemical industry is featured with a variety of comprehensive sorts of products as well as producing techniques,therefore effluent from chemical wastewater is usually with large amount,complicated ingredients,high concentration(especially COD and turbidity),which has seriously affected the ecological environment.Study on efficient and cost-effective techniques for chemical wastewater treatment is becoming one of the main focuses.Flocculation-magnetic separation technology has attracted more attention in the area of wastewater treatment in recent years.The purpose of this paper is to explore the prospective application of flocculation-magnetic separation technology in chemical wastewater treatment to provide reference for chemical wastewater treatment to meet emission standards.In this paper,the performance of flocculation-magnetic separation technology was studies to treat chemical wastewater,while removal rates of COD and turbidity were taken as indexes.First of all,the suitable flocculants was screened,and then optimization of experimental conditions was carried out through the single factor static test and orthogonal designs,in the end,the mechanisms of the flocculation-magnetic separation technology were analyzed.Results showed that,the combination of flocculants,magnetic powder and PAM is more effective than single treatment.The optimized working condition is as flow: PFS and Al Cl3 in radio of 1:1(w/w),feeding amount of 800 mg/L,and dosage of PAM and magnetic powder of 8.0 mg/L and 800 mg/L,respectively.The optimal feeding order: magnetic powder followed with flocculants and PAM,reaction temperature 30℃,static sedimentation time 25 min,and p H=6.Under the optimized condition,54.9% of COD and94.2% of turbidity were removed.Orthogonal tests showed that dosage of flocculants>p H>dosage of magnetic powder>the static sedimentation time according to their importance.The magnetic powder and magnetic flocs were analyzed with TGA,XRD,FTIR,SEM,vibrating sample magnetometer,transmission electron microscopy,optical microscopy.Results showed that the magnetic powder is mainly consisting of Fe3O4 and stable.The magnetic powder played an important role in the treatment process mainly through improving the flocculation behavior by means of adsorption bridging action.The sedimentation velocityof magnetic flocs was 480 cm/min under the outside magnetic field.Up to 99% of magnetic powder was recovered,which showed a recycling potential.Meanwhile,perspective results were obtained while applying flocculation-magnetic separation technology for oily wastewater,domestic sewage,eutrophic lake water,etc.This study provides both theoretical and applied references for highly effective chemical wastewater treatment.