生物法制备聚合硫酸铁及其应用研究_英文_Biologicalpreparationandapplicationofpoly-ferricsulfateflocculantWANGHui-min,MINXiao-bo,CHAILi-yuan,SHUYu-deSchoolofMetallurgicalScienceandEngineering,CentralSouthUniversity,Changsha410083,ChinaReceived23September2021;accepted5January2021Abstract:Anovelinorganicpolymerflocculant,poly-ferricsulfate(BPFS)waspreparedbyoxidationofferroussulfateusingdomesticThiobacillusferrooxidans(Tf)underacidcondition.TheoptimalconditionsforthepreparationwerepHvalueof1.5,(NH4)2SO4dosageof0.5g/L,initialFe2+concentrationof45g/L,inoculum10%,rotatingspeedof120r/min,reactiontimeof56dandreactiontemperatureof30C.Undertheoptimalconditions,theBPFSproductwithpHvalueof1.52.2,basicityof17.5%22.7%andtotalironcontentof43.8745.24g/Lwasobtained.TheapplicationoftheBPFStothreewastewaterswascarriedout,andtheremovalefficienciesofCOD,decolorizationandZn2+byBPFScanbereached70%,90%and99%,respectively.TheresultsuggeststhattheBPFSisanexcellentflocculantforwatertreatment.Keywords:ferrite;poly-ferricsulfate;flocculant1IntroductionFlocculationsedimentationisoneofthemostwidelyusedandlowestcosttechniquesforwatertreatment[12],andflocculantisthekeyinapplicationofflocculationsedimentationtechnique.Recently,anovelinorganicpolymerflocculant,poly-ferricsulfate(PFS)hasreceivedmuchattentionbecauseithasmanyadvantagesincomparisonwithconventionalflocculant,suchaslowsampleconsumption,highefficiency,widepHapplicationrange,lowresidualironconcentration,hydrolysatewithhighefficientlydehydration,non-toxicity,low-pricedandfastsettlingrate[36].Atpresent,PFSismostlypreparedbydirectoxidationofferroussulfateusingstrongoxidantsuchasH2O2,KClO3,NaClO,HNO3orbycatalyticoxidationofferroussulfateusingNaNO2orNaIasacatalystinacidmedia.However,themethodsmentionedabovehavemanylimitationssuchasextremelyslowreaction,unstableproduct,lowyield,largeconsumptionofcatalyst,highcostandemissionsofnitrogenoxidescausingenvironmentalpollution,soitisdifficulttobeappliedtotheindustrialproduction[710].TheobjectiveofthisstudyistodevelopanewpreparationtechniqueforPFSusingthemicrobesandorganicwaste,andtogaintheBPFSproductwithlowcost,lowenergyconsumption,high-qualityandhighstability[1114];theinfluencingfactorsinthepreparationprocessofBPFSanditsapplicationinwatertreatmentwerealsoinvestigated.2Experimental2.1Microbialadaptation9Kculturemediumcontaining9g/LFe2+wasaddedintoconicalflask，then10%(volumefraction)inoculumwasinnoculatedandcultivatedonathermostaticwaterbathat30Cwithagitationof120r/min.TheconversionrateofFe2+wasdeterminedatselectedtimeuntilitreached85%.Afterthereaction,thereactionmixturewasusedtoinitiatethenextone,andtheabove-mentionedstepswerereplicateduntilthereactiontimebasicallyremainedstable.Withtherepeatedinoculationandcultivation,Tfbacteriagraduallyadaptedtothenewenvironment,andthereactiontimegraduallybecamestable.TheTfbacteriaadaptationresultsarelistedinTable1.AstheTfbacteriawereinanewenvironment,theirgrowthandoxidabilitywereinfluencedtoacertainextent.ThereactiontimetomeettheoxidationrateFoundationitem:Project(2021ZX07212-001-01)supportedbytheMajorScienceandTechnologyProgramforWaterPollutionControlandTreatment,China;Project(50925417)supportedbytheNationalNaturalScienceFoundationforDistinguishedYoungScholarsofChina;Projects(50830301,51074191)supportedbytheNationalNaturalScienceFoundationofChinaCorrespondingauthor:MINXiao...