不同价态阳离子盐改性沸石吸附氨氮能力差异

采用5种不同价态阳离子盐对天然斜发沸石进行改性,通过SEM,EDS,ICP以及氮吸附分析仪等测试手段对改性前后的沸石颗粒进行表征,发现不同价态阳离子和相同价态不同阳离子的盐改性沸石后对其物化性质和应用性能均会产生影响.EDS及ICP测试发现由于离子交换作用改性后沸石中5种盐对应的金属阳离子含量均会升高,其中KCl改性沸石中钾元素含量增加量最多.比表面积与孔径分布测试结果发现随着阳离子价态升高,沸石比表面积下降幅度逐渐增大,其中一价钾盐的改性沸石比表面积下降幅度最小为33.9 m2/g,三价铝盐下降幅度最大为29.27 m2/g;而改性沸石孔体积变化规律有所不同,其中一价盐改性沸石介孔体积增加量最大、大孔体积减少量最多.对不同价态阳离子盐改性沸石进行了阳离子交换容量和污水脱氮能力测试,结果表明,其阳离子交换容量和脱氮能力大小排序为:NaCl＞AlCl3＞CaCl2＞MgCl2＞KCl.说明改性沸石的污水脱氮能力与其阳离子交换容量呈正相关关系,但是阳离子价态的高低与改性沸石的阳离子交换容量、比表面积、孔体积和脱氮能力并不是正相关关系.
Natural clinoptilolite were modified by five different valence state cationic salts. The differences of adsorption ability to ammonia nitrogen were studied with particle morphology, channel characteristic, cation exchange capacity and adsorption ability to ammonia nitrogen taken as evaluation indexes. EDS test revealed that the metal cation content corresponding to five kinds of modified salts in the clinoptilolite will increase with K+ increasing most in KCl modified clinoptilolite. The results of specific surface area and pore size distribution test indicated that the specific surface area of KCl modified clinoptilolite decreased least, whereas AlCl3 modified zeolite dropped most. The mesoporous volume of NaCl and KCl modified clinoptilolite increased most, but macroporous volume reduced most.However the clinoptilolite modified by MgCl2 and CaCl2 showed little change. Cation-exchange capacity order of the modified zeolite was NaCl＞AlCl3＞CaCl2＞MgCl2＞KCl. The ability of clinoptilolite for removing ammonia nitrogen was found to be positive correlation with cation-exchange capacity, but there was a big difference in the cation-exchange capacity of salt modified zeolite with the same valence. The results indicated that the cation valence was not positive correlation with cation-exchange capacity and ammonia nitrogen removing ability.