Thermodynamic study of lead ion removal by adsorption onto nanographene sheets

A batch adsorption study was applied to investigate the adsorption of Pb2+ ions from aqueous solutionby nanographene (nG).The adsorption percentage of Pb2+ions onto nG samples at different initial pH,contact time (tc), adsorbent dosage (mnG) and temperature (T) were investigated. The results showedthat nG is an excellent adsorbent for Pb2+ions removal from aqueous solutions with an adsorptionpercentage of up to 79.8% at initial Pb2+concentration of 20ppm and temperature of 298K.Theexperimental data could be well described by the Freundlich and Langmuire isotherm model;thermodynamic parameters of adsorption process (AG0, AH0, ASo) were also evaluated. The overalladsorption process was exothermic and spontaneous in nature .The results indicate that Pb2+ionsadsorption onto nG may be chemisorption.