Adsorption performance and mechanism investigation of Mn~(2+) by facile synthesized ceramsites from lime mud and coal fly ash

摘要

To efficiently control manganese pollution, two kinds of ceramsites with pH self-adjustment ability, being synthesized from lime mud and coal fly ash, were employed to remove Mn2+ from aqueous solutions. The influence of different parameters like contact time, concentration of Mn2+ and pH on adsorption performance was examined. Also, the mechanism of Mn2+ removal by the ceramsites was investigated thoroughly. The results showed that the maximum Mn2+ adsorption capacity of ceramsites was 2.54 +/- 0.03 mg/g and the time required to reach equilibrium was about 4h. The pseudo-second-order kinetic model and the Langmuir model could better describe the adsorption kinetic experimental data and isotherms process, respectively. During the adsorption process of Mn2+, pH self-adjustment ability of ceramsites played a leading role in creating an alkaline environment to form precipitation MnO(OH)(2), which was subsequently adsorbed onto the surface of the ceramsites. This study suggests ceramsites with pH self-adjustment ability have enormous potential in the application for removing Mn2+ from wastewater.