铵饱和沸石再生机理研究

RESEARCH ON MECHANISM OF SATURATED ZEOLITE REGENERATION

利用浙江缙云产天然沸石,对其分别进行静态吸附和再生处理,从而进行沸石再生途径的探索和再生最优条件的选择。实验表明,在沸石初次再生中,沸石再生过程的三个途径为:1盐溶液对NH+4的解吸;2盐溶液对K+、Ca2+、Mg2+的置换;3盐溶液对沸石表面形态进行改性,其中影响作用的大小顺序为1>3>2。而在其中途径2中,各阳离子的作用大小顺序则为Ca2+>K+>Mg2+;随着再生次数的增多,盐溶液对NH+4-N的解吸在再生过程中所发挥的作用逐渐增强,最终成为决定性因素,而另外两途径的影响力则逐渐减弱,途径2最终失去了再生效果;对于短期使用的沸石,其最优再生条件应以沸石再生后的吸附量大小来确定,再生时选用氯化钠溶液作为再生剂效果较好,长期使用的沸石,则应以盐溶液对沸石的解吸量大小来确定,此时氢氧化钠溶液较为合适;试验同时表明5 g/L的钠离子浓度为最优钠离子浓度。其次,OH-对于吸附了NH+4-N的饱和沸石的解吸具有促进作用,而温度对再生的影响并不明显。

The natural zeolite produced in Zhejiang Jinyun was used to investigate the zeolite regeneration and corresponding regeneration parameters through static adsorption and regeneration experiments.Results showed that during the initial regeneration of the zeolite,there were three ways in the zeolite regeneration process: 1 Desorption of NH+4by salt solution;2 Replacement of K+,Ca2 +and Mg2 +by salt solution; 3 Modification of zeolite morpholoty by salt solution,in which the proportion of contribution was 1 > 3 > 2.It was also found that in way 2,the influence of cation was Ca2 +> K+> Mg2 +;With the regeneration frequency increases,the desorption of NH+4-N by salt solution in the regeneration process gradually became the dominant factor,while the contribution of the other two pathways decreased,pathway 2 eventually lost its effect.For short-term use of zeolite,the optimal conditions should be determined by the adsorption capacity of regenerated zeolite,and sodium chloride solution was the best; for the long-term use of the zeolite,the regeneration parameters should be determined by the desorption capability of salt solution,and sodium hydroxide solution was more appropriate.Test results also showed that 5 g /L of sodium ion was the optimal concentration.Secondly,desorption of NH+4-N saturated zeolite can be promoted by OH-,and the temperature had no obvious impact on regeneration.