改性斜发沸石处理高浓度氨氮废水

采用NaOH碱熔法对缙云斜发沸石进行处理,采用正交实验对碱熔法改性沸石的最佳条件进行了选择;并对改性前后的沸石进行粉末X射线衍射(XRD)、电感耦合等离子体发射光谱法(ICP-AES)和扫描电镜(SEM)表征;详细研究了所得改性沸石在氨氮废水处理中的净化性能.结果表明,处理沸石的水热温度对氨氮去除效果的影响最显著;碱熔法处理可使缙云斜发沸石转变为低硅铝比的Na-P型分子筛,它对氨氮废水的NH4+-N具有优异的吸附性能.当改性沸石投加量为5 g,对100 mL浓度为1000 mg.L-1氨氮溶液,氨氮去除率可达77.8%,改性沸石吸附NH4+-N是一快速吸附过程,且能较好地符合Langmuir吸附等温模式,偏向于单分子层的吸附.

Removal of ammonnia-nitrogen in simulated NH_4~＋-N wastewater with modified clinoptilolite

The Chinese natural clinoptilolite was modified by alkali fusion and hydrothermal treatment.The modified clinoptilolite was characterized with X-ray diffraction(XRD),inductively coupled plasma-atomic emission spectrometry(ICP-AES),and scanning electron microscopy(SEM).The orthogonal experiment with 5×6 factors showed that the temperature of hydrothermal treatment was the most significant factor for the modification of clinoptilolite.The modification processes led to the formation of the Na-P zeolite with lower Si/Al molar ratio,thereof their capacity for adsorbing NH+4-N was enhanced.Using 5 g of modified clinoptilolite,the removal rate of NH+4-N in 100 mL simulated wastewater(NH4Cl 1000 mg · L-1) was up to 77.8% under the optimum conditions.Moreover,the adsorption of NH+4-N on clinoptilolite is a rapid process,which accords with Langmuir isothermal adsorption model.