微孔分子筛的合成及其去除水中氨氮的实验研究

以廉价的天然矿物岩石作为主要原料,采用水热晶化法合成了微孔分子筛。分子筛有效孔径约为0.9 nm,BET比表面积583m2/g,阳离子交换容量(CEC)316 meq/100 g。将其用于水体中氨氮的去除,实验结果表明,分子筛对氨氮的吸附速率较快,吸附时间为20 min时,吸附基本达饱和;分子筛对氨氮的最大吸附量可达11.6 mg/g,其吸附规律很好地符合Fruendlich吸附等温式;在有干扰离子如Ca2+、Mg2+、Al3+和Fe3+等存在的情况下,仍能优先选择吸附NH4+,且吸附率几乎没有变化。动态吸附柱实验的效果好于静态实验,出水12 h内去除率均>85％;饱和了氨氮的分子筛,用氢氧化钠溶液洗脱再生,解吸率达92％,再生后的分子筛与原分子筛相比吸附率几乎没有降低。

The experimental study on synthesis of microporous molecular sieves and its application to purifying wastewater with ammonium

Microporous molecular sieves was synthesized by hydrothermal synthesizing technique from natural rock. Its effective aperture is 0.9 nm and ratio surface area of BET is 583 m2/g. The capacity of its exchangeable cation is 316 meq/100g. Its application to adsorbing ammonium in water was experimentally investigated. The results showed that the ratio of adsorption reached a plateau value when the adsorption time was 20 min. The saturation adsorbing capacities of ammonium is 11.6 mg/g, and regularity of adsorption accorded with isothermal adsorption model of Fruendlich. When there were several cation , such as Ca2+ .Mg2+.Al3+ .Fe3+ , molecular sieves could prefer adsorbing NH4+. The ratio of removing ammonium in drainage is higher than 85% during 12 hours by dynamical experiment . Spent molecular sieves could be regenerated by NaOH solution without noticeable loss of capacity. Experimental researches indicate that molecular sieves is suitable for the purification of ammonium-bearing wastewater.