锰氧化物改性分子筛的制备及其在含酚废水处理中的应用

根据催化氧化原理，利用4A分子筛为载体，次氯酸钠（NaClO）为氧化剂，通过硫酸锰（MnSO₄）在其表面的原位氧化来制备对环境无害的锰氧化物（MnO_x）改性的分子筛（MnO_x@MS）材料.通过场发射扫描电镜（FE-SEM）和X射线衍射（XRD）对材料进行了表征.XRD分析表明：Mn元素是以MnO_x形式存在，在pH为7.2时，反应得到的MnO_x中Mn离子的价态最高.测试表明：Mn离子的价态越高对含酚废水的处理效果就越好.采用在最优条件下得到的MnO_x@MS材料作为催化剂，对过氧化氢（H₂O₂）氧化降解含酚废水进行研究，考察了不同体系、温度、pH值和H₂O₂用量对苯酚降解的影响.结果表明：在优化的降解条件下，120 min内，未改性分子筛对苯酚的去除率仅为35%，而MnO_x@MS改性材料对苯酚的去除率达到82%，说明通过MnO_x改性后的分子筛，对苯酚的氧化降解能力大大提高.

Preparation of manganese oxide modified molecular sieve and its application in the treatment of phenol containing wastewater

An environmentally safe manganese oxide (MnO_x) modified molecular sieve (MnO_x@MS) for the effective treatment of phenol containing wastewater was prepared via an in situ oxidation of manganese sulfate(MnSO₄)on the surface of 4A molecular sieve with sodium hypochlorite (NaClO) as the oxidant. The materials were characterized by field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). XRD analysis showed that manganese was present in the form of manganese oxides. The manganese oxide had the highest valence state when the reaction pH was 7.2. The results showed that the higher the valence of manganese ion in manganese oxides, the better the treatment effect of phenolic wastewater was. The oxidative degradation of phenol-containing wastewater by hydrogen peroxide was studied using manganese oxide modified molecular sieve as the catalyst under the optimum preparation conditions. The effects of different systems, wastewater temperature, pH value of wastewater, and the amount of hydrogen peroxide on the degradation of phenol were investigated. The results showed that under the optimum degradation conditions of wastewater, within 120 min the removal rate of phenol by the unmodified molecular sieve was only 35%, while that of phenol by manganese oxide modified molecular sieve was 82%, indicating that the oxidative degradation performance of phenol by manganese oxide modified molecular sieve was greatly improved.