Synthesis of novel hierarchical porous zeolitization ceramsite from industrial waste as efficient adsorbent for separation of ammonia nitrogen

In this study, a green process of high temperature sintering activation + hydrothermal reaction for the synthesis of novel zeolitization ceramsite from industrial wastes was designed. The synthesis process of zeolitization ceramsite was studied by XRD, SEM and FT-IR. The adsorption process of ceramsite was described by experiments and various kinetic model and isothermal adsorption model. The results show that the optimum preparation conditions were as follows: sintering temperature at 1040 ℃, hydrothermal temperature at 160 ℃, NaOH concentration of 3 mol/L and time of 12 h. XRD and FT-IR showed that the modified ceramsite was loaded with cancrinite zeolite crystals, which was the main reason for the increase of specific surface area from 1.259 m2/g to 17.92 m2/g. Furthermore, the adsorption capacity of ammonia nitrogen increased from 2.02 mg/g to 19.9 mg/g. The adsorption mechanism of ammonia nitrogen by ceramsite was mainly ion exchange, which also accords with the structural characteristics of zeolite. The results are highly attractive for many industrial applications due to the simplicity and green of the synthesis procedure and remarkable adsorption properties.