Effect of Municipal Sludge Ceramsite on Cd2+Adsorption Char-acteristics
In order to expand the means for the resource utilization and innocent treatment of municipal sludge,this study employed high temperature sintering to prepapre municipal sludge ceramsite with munici-pal sludge,clay,and bentonite as raw materials.Taking the wastewater containing Cd2+as a pollutant,this study examined the influences of the addition of municipal sludge ceramsite,the initial pH value of solution,the adsorption time,and the initial concentration of Cd2+on the adsorption property of ceramsite.At the same time,the adsorption kinetics and isothermal adsorption characteristics were studied,and the unique adsorption mechanism was revealed by X-Ray Diffraction(XRD),Scanning Electron Microscopy(SEM)and other char-acterization methods.The results showed that:① After sintering,the municipal sludge ceramsite presented a rough surface,a pore structure,and abundant functional groups;② Quartz(SiO2),mullite(Al6Si2O13),calci-um feldspar(CaAl2Si2O8),and hematite(Fe2O3)were the main crystalline phases of municipal sludge ce-ramsite,and the mineral composition was unchanged after adsorption of Cd2+;③ Under certain conditions(addition of 50 g ceramsite,the initial Cd2+concentration of 300 mg/L,the adsorption time of 120 min,and pH value of 6),the removal rate of Cd2+was high,indicating the high ability of ceramsite to adsorb Cd2+;④ The municipal sludge ceramsite adsorbed Cd2+in two manners:physical adsorption and chemisorption.The adsorption conformed more to the quasi-first-order kinetic model than to the quasi-second-order kinetic model.The municipal sludge ceramsite adsorbed Cd2+via a complex mechanism involving both single-layer and multi-layer adsorption.The results can provide a scientific basis and technical support for the resource u-tilization of municipal sludge and the treatment of Cd2+and pollutants.
municipal sludge ceramsitecadmium-containing wastewateradsorption kineticsadsorption iso-thermadsorption mechanism
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