The Study Of Adsorption Of Pb(Ⅱ) And Methylene Blue By Graphite Oxide Coated On Sand Filter Surface

Heavy meta l and dye io ns both will pollute environment, especia lly for aqueoussystem. The water qua lity will be bad even be poisono us once these pollutant existingin water, and moreover, the aquatic organis m and human beings will be threatened.However, they are usually be together which makes it difficult to remove.Graphite oxide (GO) is a k ind of o nly o ne carbon atom thickness of2Dnano-materia ls, and contains a lot of oxygen functiona l groups inc lud ing hydroxyl,carboxyl and carbonyl on surface. The functiona l groups a re the potentia l adsorptio nsites. Due to the larger specific surface area and the advantages of high re mova leffic iency o f GO, it attracts more and more researchers to study its improve me nt. Inthis study, GO was prepared by Hummers method and loaded to t he sand surfaceunder the cond ition of high temperature as a new form of adsorbent (GO-sand), forthe adsorption removal of Pb (II) and methylene blue (MB).In this study, a continuous adsorption of Pb (II) and methyle ne blue (MB) hasbeen stud ied in s ingle and binary solutions by us ing graphite oxide coated sand(GO-sand) as an adsorbent in a fixed-bed column. GO-sand was analyzed by X-rayphotoelectron spectroscopy before and after analyte adsorption. Compared with sandfilter, adsorption qua ntity and capacity for Pb (II) and MB by GO-sand filter weregreatly increased. In Pb (II) and MB s ingle so lutio ns, the experimenta l parameterswere investigated in detail inc lud ing initial concentration, flow rate, bed depth and pH.Exhaustion time decreased with increasing initia l concentration and flow rate andincreased with increasing bed depth and pH. In the Pb (II)-MB binary solution,exhaustio n time significantly decreased for Pb (II) adsorption, but increased for MBadsorption. The reason was expla ined that the more favorable adsorption for MB ontothe surface of GO-sand than that for Pb (II), which was derived from π-π interactionbetween MB and GO on sand s urface in packed filter. The Yoon-Nelson model wasapplied at different concentration of Pb (II) and MB to predict the breakthroughcurves. The experimenta l data were well fit with the model ind icating tha t it wassuitable for this column design.