| Zeolite is a kind of silicon aluminate crystal with uniform channel and the molecular level of pore size,which can be used as an excellent adsorbent.The resources of coal-measure kaolin are widely distributed and cheap in China.Because the ratio of Si/Al is close to that of zeolite,and has high reactivity,it is suitable for the synthesis of zeolite that was calcined in certain temperatures.In this paper,calcined kaolin is used as raw material to synthesize molecular sieve.On one hand,it can replace traditional chemical raw materials,effectively reducing the production cost of molecular sieve,and achieving comprehensive utilization of environmental mineral resources,which have research value,application value and economic benefit.The main work of this paper is as follows:（1）13X zeolite was synthesized by hydrothermal synthesis,microwave synthesis and two-step method of microwave-hydrothermal from coal-measure kaolin.Three methods all can synthesize 13X zeolite with good crystallization and neat shape.The influences of synthetic include pre-crystallization conditions,crystallization conditions,seed dosing quantity,formula and so on.Zeolite synthesized by two-step method of microwave-hydrothermal is uniform.The particle size is about 2μm.The rate of static saturated water absorption can reach 35.44%.Crystal nucleus growed rapidly at the pre-crystallization stage because of microwave action.The solubility and reactivity of the reactants were increased in the crystallization process because of mild hydrothermal conditions.The grain keeps growing because of rearranging and dissolving of the primary gel that was first produced.（2）The feasibility of synthesizing NaA zeolite by two-step method of microwave-hydrothermal from coal-measure kaolin was verified.The results showed that the optimized reaction conditions were as follows.Na2O/SiO2=3.00,H2O/Na2O=40.The best dosage seeds was 2%.Pre-crystallization time was 40min,pre-crystallization temperature was 70℃in 300W.Crystallization time was 6h in 100℃.The crystallinity of zeolite is high.The morphology is homogeneous.The particle size is about 3.54.5μm.（3）With lead ion(Pb2+)as the representative,the effect of the adsorption rate on heavy metal ions was investigated by using three kinds of 13X zeolite as adsorption materias.The result showed that zeolites synthesized by hydrothermal synthesis,microwave synthesis and two-step method of microwave-hydrothermal were respectively conform to the Lagergren secondary adsorption rate equation.Saturated adsorption capacity of Pb2+was 507.01 mg/g,591.71 mg/g and 507.01 mg/g.The zeolite is suitable for the treatment of Pb2+wastewater treatment,and the final concentration can reach the sewage discharge standard of less than 1mg/L（a class of pollutants）. |
