Adsorption performance and mechanism investigation of Mn2+ by facile synthesized ceramsites from lime mud and coal fly ash

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 Mn 2+ from aqueous solutions. The influence of different parameters like contact time, concentration of Mn 2+ and pH on adsorption performance was examined. Also, the mechanism of Mn 2+ removal by the ceramsites was investigated thoroughly. The results showed that the maximum Mn 2+ 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 Mn 2+ , 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 Mn 2+ from wastewater.