碱改性净水污泥对水中氨氮的吸附效能研究

采用氢氧化钠浸渍法改性净水污泥,研究了碱改性净水污泥对水中NH+4的去除性能.同时,考察了模拟废水pH、吸附剂投加量、NH+4初始浓度、吸附温度及吸附时间对吸附性能的影响.结果表明,当pH为弱酸性或中性,投加碱改性净水污泥20 g·L-1时,在室温下对初始浓度为50 mg·L-1的NH+4模拟废水振荡吸附120 min,可达到氨氮排放二级标准.将实验数据分别用吸附等温模型和动力学模型进行拟合,发现净水污泥对NH+4的吸附符合Langmuir模型和二级动力学模型,且净水污泥对氨氮的吸附包括静电吸引和离子交换两种作用机理.

Adsorption efficiency of alkali-modified water treatment sludge for ammonia nitrogen in water

In this study,alkali-modified water treatment sludge was prepared by impregnated in NaOH.The obtained adsorbent was further applied to remo-ve NH⁺₄ excessive from water.The adsorption efficiency was influenced by simulated wastewater pH,the dosage,initial NH⁺₄ concentration,the temperature and time of adsorption,which were investigated in detail.It was indicated that in weak acid and neutral condition the final concentration of NH⁺₄ in simulated wastewater could reach the secondary sta-ndard of ammonia emissions standard after 120 min adsorption at room temperature at the dosage of 20 g·L^-1 for the initial NH ⁺₄ concentration of 50mg·L^-1.The experimental data were fitted to adsorption isothermal models and kinetic models,respectively.It was found that Langmuir isotherm model and pseudo-second order kinetic model were the best fit.The adsorption mechan-ism of NH⁺₄ was proven to be electrostatic attraction and ion-exchange.