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    改性沸石造粒对氨氮的吸附性能

    Adsorption Performance of Modified Zeolite Granulation on Ammonia Nitrogen

    • 摘要: 以改性沸石为原料,添加聚乙烯醇(PVA)和碳酸氢钠(NaHCO3),制备出脱氨氮颗粒材料(MZ),并探究了投加量和pH值等因素对氨氮(NH4+-N)吸附性能的影响。结果表明,在MZ投加量为5 g/L,初始pH值为7的条件下,MZ对NH4+-N的去除率为94.0%。溶液初始pH值过高或过低均会降低MZ对NH4+-N的吸附效果。MZ对NH4+-N的吸附符合准二级动力学模型和Freundlich吸附等温线模型,且吸附过程受液膜扩散和颗粒内扩散共同控制,对NH4+-N的饱和吸附量为8.47 mg/g。4种常见的阳离子对MZ吸附NH4+-N表现出抑制作用,影响顺序为K+ > Na+ > Ca2+ > Mg2+。经5次循环再生后,MZ仍能保持80%以上的NH4+-N去除率。结合材料表征分析结果,MZ对NH4+-N的吸附主要是以离子交换为主的化学吸附,同时具有一定的物理吸附作用,但作用程度较小。

       

      Abstract: A nitrogen removal granular material (MZ) was prepared from modified zeolite with the addition of polyvinyl alcohol (PVA) and sodium bicarbonate (NaHCO3), and the effects of factors such as the dosage and pH on the adsorption performance of ammonia nitrogen (NH4+-N) were investigated. The results showed that the removal rate of NH4+-N by MZ was 94.0% under the conditions of MZ dosage of 5 g/L and initial pH of 7. The adsorption process of NH4+-N by MZ was in accordance with the quasi-secondary kinetic model and Freundlich adsorption isotherm model, and this process was jointly affected by liquid film diffusion and intra-particle diffusion, and the saturated adsorption amount of NH4+-N was 8.47 mg/g. The four common cations showed inhibitory effects on the adsorption of NH4+-N by MZ in the order of K+ > Na+ > Ca2+ > Mg2+. After five cycles of regeneration, the MZ could still maintain more than 80% of NH4+-N removal. Combined with the analytical results of material characterization, the adsorption of NH4+-N by MZ is mainly due to chemical adsorption based on ion exchange, while physical adsorption contributes less.

       

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