PHOTOCATALYTIC DEGRADATION OF SELECTED ENVIRONMENTAL ORGANIC POLLUTANTS USING A GREEN SYNTHESIZED Mn3O4ZnO/Co34 NANOCOMPOSITE

Abstract

ABSTRACT

Thepresenceoforganicpollutantsinwastewaterposessignificanthealthrisksto humans andaquaticecosystems. Photocatalyticdegradation hasemerged asoneofthe highlyeffectivemethodsforremovingthesepollutants.Thisstudyinvestigatedthe photocatalyticdegradationofselectedEnvironmentalOrganic Pollutants (EOPs) using agreen-synthesizedMn3O4tZnO/Co3O4(MZC)nanocomposite.TheMZCwas preparedthroughenvironmentallyfriendlymethodsthatutilizednon-toxicreagents andsustainableprocesses.Thiswasachievedbyusingmanganese(II)acetate tetrahydrate,zincnitratehexahydrate,cobalt(II)chloridehexahydratealongwith Moringaleafextractviaa simplesingle-stepcombustionmethod.Thematerialwas characterizedbyFourierTransformInfraredspectroscopy(FTIR),Ultraviolet-Visible spectrometry(UV-Vis), Scanning Electron Microscopy(SEM), TransmissionElectron Microscopy(TEM) andX-Ray Diffraction(XRD).Batch degradationexperimentsof MZC on Ciprofloxacin hydrochloride (CIP), Amoxicillin trihydrate (AMX), PolyethyleneGlycol(PEG)andDiethylphthalate(DEP)wereconductedunder varying conditions:pH (3 - 9), timeintervals(30 - 180 minutes),temperatures(25- 45°Cat 10°Cinterval) and catalystdoses (0.05- 0.15 g). The optimizedconditions were then appliedto raw samplesproducedwastewater(RPW)from oil mining.The degraded wereanalyzedusingUV-VisandGasChromatography-Mass Spectrometer(GC-MS).TheFTIRanalysisofthepreparedMZCnanocomposite acharacteristicstretchingvibrationsat3257,2325,1650,and1095cm', C-O-Cgroups,respectively.TheXRDdiffractogram of MZC showed sharp peaks at 28 of 12, 21 and 26°, which ascertained the crystallinity ofMZC.TheTEMporositydimension rangedfrom 20-50rim,showing the mesoporous nature of the material while the SEM micrograph revealed surface morphology with significant porosity. The highest degradation obtained for CIP, AMX,PEG,andDEPwere99.98%,25°C;53.5%atpH9,45°C;69.20%atpH9, 45°Cand76.9%atpH9,45°Crespectively.TheGC-MSresultsrevealedthatmajority ofthe compounds weredegraded. The CIP degradation showed theformation ofnew compounds: 2,3,7-trimethyldecane and 2-bromotetradecane after 150 minutes; while that of PEG showed the formation of8-methylheptadecaneand heptaethylene glycol after 60 minutes, and DEP degraded completely. There were also formation of new compounds: 24-Norursa-3,12-dien-11-oneand O1ean-12-en-3-ol from the RPW. The study showed that the synthesized Mn3O4tZnO/Co3O4»anocomposite effectively degraded the selected organic pollutants and hence can be used as a facile and cost effective material for waste-water purification.