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Controlofwaterpollutionisagreatchallengeof2lstcentury.Avarietyofprocessesarereportedforwastewatertreatment;eachhasitsownadvantages.However,acompletetreatmentrequiresseveralstepsandanappropriatecombinationofmethods.Itwasenvisagedtodevelopaquaternarynanocompositethatwouldcombinethepropertiesofthecomponentswithdifferentcharacteristics.Coagulation/flocculationisapopularprocessfortreatmentofindustrialwastewaterwhichemploysmineraladditives,polyacrylamideanditsderivatives.However,theseadditiveshaveconsequentialadverseimpactontheenvironment,suchasincreaseinmetalionconcentration,productionoflargevolumesoftoxicsludge(difficulttodehydrate),contaminationthroughdispersionofoligomersinwater.Chitin/chitosanandcellulosicmaterialshavebeenreportedtoadsorbmetalionsfromaqueousandnon-aqueoussolutionsbychelatingcoordination.Organoclayshaveproventobeefficientfortreatmentofwaterthatcontainssubstantialamountsofoil,greaseand/orhumicacid.Ananocomposite(NCPAAm)waspreparedfromsugarcanebagasse,chitinandfuller,searthbyin-situintercalativepolymerizationofacrylamide,usingpotassiumpersulphateasafree-radicalinitiatorandN,N‘-methylenebisacrylamideasacrosslinkerandmicrowaveradiationasanenergysource.Theresultingmasswasthoroughlyextractedwithwatertoeliminatelooselyboundmaterial.Thecompactmasswasthendriedinanairoven.SwellingbehaviourofnanocompositesampleswasdeterminedatpH4.0,pH9.2andpH7.0;andinwater,methanol,acetoneandchloroformrespectively.NCPAAmexhibitedveryhighswellinginalkalinesolutionasamidegroupswerehydrolyzedtocarboxylicacidgroupswhichwasstronglyhydrophilicenhancedadsorptionofwater.SwellingwasfoundtobemoderateinNaCIsolutionandminimuminacidicsolutions.Aninsignificantamountoferosionwasfound,inwater,acid,alkaliandsaltsolutions;aswellasinorganicsolvents,whichindicatedthatthenanocompositesweremechanicallyquitestable.Thoughmicrobialgrowthdevelopedonthebio-materialsusedinthispreparationunderwetconditionwithinaweek,suchgrowthwasnotobservedforthenanocompositesevenafteramonth.Thenanocompositesexhibitedstrongadsorptiontendencyformethylorangeasamodeldye.Adsorptionwasquiteefficientandbetterresultswereobtainedwiththelowerinitialconcentration.Thenanocompositesamplesadsorbedmetalionsviz,nickel,copper,manganese,mercuryfromtheaqueoussolutionsandroughsurfaceofnanocompositesbecamesmoothvisibly.TheresultsfromatomicabsorptionspectroscopicmeasurementshowedalmostquantitativeadsorptionforImmol/Lconcentrationofmetalionsolutions.ForcopperandnickelionsthebluecolouredcrystallinematerialcoveredthevoidsclearlyvisibleinSEM.TheFTIRspectraofmetalionadsorbedsamplesindicatedstronginteractionwiththeadsorbent. |
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