Study On Photocatalytic Performance And Adsorption Properties Of Fe₃O₄/GO On Pharmaceutical Wastewater

The pharmaceutical industry is not only an important pillar industry in China,but also a social welfare undertaking for the treatment,prevention,health care,and family planning.However,the problem of prevention and control of wastewater pollution caused by the pharmaceutical industry has restricted its development for many years,and is a major environmental protection problem facing society today.Pharmaceutical wastewater has complex water quality,many intermediate products,strong toxicity,high salinity,high COD,high ammonia nitrogen concentration,poor biodegradability,and it is difficult to degrade by biological methods.In recent years,light Fenton and adsorption methods have been widely used in the treatment of pharmaceutical wastewater.Graphene is used as the raw material,and modified Hummers is used to make graphene oxide（GO）.The complexation reaction with ferric chloride（Fe Cl₃·6H₂O）under alkaline conditions under high temperature and pressure conditions results in the synthesis of graphene-supported nano-iron iron oxide（Fe₃O₄/GO）magnetic catalyst.X-ray diffractometer（XRD）,scanning electron microscope（SEM）,EDS,Fourier infrared spectrometer（FT-IR）were used to characterize the synthesized materials.The XRD diffraction pattern shows that the synthesized Fe₃O₄/GO has obvious characteristics in six positions,such as（30.1°）,（35.4°）,（43.8°）,（54.8°）,（57.2°）,and（63.1°）.The peaks correspond to the（220）,（311）,（400）,（422）,（511）,and（440）crystal plane diffraction peaks in the iron oxide crystal structure.The SEM scan image can support Fe₃O₄particles on the GO surface.Fourier transform infrared spectroscopic analysis showed that graphite had introduced alkoxy（-OCH₃）,epoxy bond（C-O-C）,carbonyl（C=O）,hydroxyl（-OH）,carbon-carbon double Functional groups such as bonds（C=C）,Fe₃O₄/GO also contains Fe-O bonds.UV-Vis absorption spectrum shows that GO has an absorption peak at around 230nm,while graphene oxide-loaded nano-iron tetroxide（Fe₃O₄/GO）has a small absorption peak at around210nm.Firstly,using the prepared Fe₃O₄/GO as a catalyst to construct a photo-Fenton system for the treatment of chemical raw material wastewater.The test mainly used COD as an index to examine the various influencing factors of the Photo-Fenton system to obtain the optimal reaction conditions.When the wastewater p H was 3,H₂O₂（30%）was potency at 0.1mol/L,Fe₃O₄/GO was added at 2.0g/L,and the reaction was performed for 120min.The COD removal rate was 88.1%,the BOD removal rate was 84.1%,and the biodegradability of the wastewater From 0.22 to0.46,the biodegradability becomes better.The mechanism of treatment of chemical drug substance wastewater by the light Fenton system was analyzed.The wastewater is mainly degraded through the following three ways:·Hydroxygen can be produced by photo-Fenton-catalyzed reaction to degrade large molecules and small molecules;and heterocyclic organic compounds with complex structures in the feedwater.Under the action of·OH,the ring structure Destroyed,H₂O and CO₂and some intermediate products with simple molecular structure were finally produced;the organic alcohols in the influent accounted for the largest percentage,the linear alkanes in the effluent accounted for the largest percentage,and a certain percentage of halogenated Hydrocarbons and alcohols will ring-open and undergo substitution and elimination reactions to produce halogenated hydrocarbons and alkanes.Next,the produced Fe₃O₄/GO was used as an adsorbent to treat chemical raw material wastewater.The test mainly used COD as an index to investigate the factors affecting adsorption,and the optimal adsorption conditions were obtained.When Fe₃O₄/GO was added at 3.0g/L,the reaction time was 10h,and the COD removal rate was 64.5%.The Fe₃O₄/GO adsorption treatment of chemical raw material wastewater is a mixed type adsorption,which is convenient for recycling and regeneration,and has high reusability.