Monolithic porous rectorite/starch composites: fabrication, modification and adsorption

摘要

The monolithic rectorite/starch composites (PRSs) were fabricated by freezing the composite gels and exchanging ice with ethanol to obtain the porous structures. The rectorite layers were randomly oriented and covered with starch in the monolithic PRSs. Two modifications were treated without destroying the porous structures. Starch components were removed to obtain the calcinated PRSs (CPRSs); and starch components reacted with carbon disulfide to obtain the porous rectorite/starch xanthate composites (PRSXs). PRSs, CPRSs and PRSXs exhibited low density and high liquid adsorption due to the porous structures. CPRSs possessed the higher MB adsorption capacity than PRSs, because the resistance of starch on MB adsorption was eliminated. The chelation could form between xanthate groups and Pb (II), and improve the adsorption of Pb (II) of PRSXs. The maximum adsorption capacities could reach 277.0 and 180.8 mg g(-1) for MB by CPRS and Pb (II) by PRSX, respectively. Moreover, CPRS could be effectively recycled by burning away the adsorbed MB dye; while PRSX could be easily regenerated with ethylenediaminetetraacetic acid disodium salt (EDTA) solution. The modification of PRSs had the potential applications on the treatment of cationic contaminations in water. (C) 2015 Elsevier B.V. All rights reserved.