吸附-磷酸铵镁结晶耦合法去除低浓度氨氮

Adsorption - Struvite crystallization coupling method removes low concentrations of ammonia nitrogen

摘要:

摘要：以活性白土为原料，通过复合改性制得载镁活性白土（AC-Mg），作为高效吸附剂，与模拟废水中的低浓度氨氮和磷反应，通过对改性活性白土和反应后的回收产物进行BET、XRD、SEM、FTIR和粒径进行分析。探究该方法对低浓度氨氮去除和回收的机理，反应温度和溶液初始pH对效果的影响。结果表明氧化镁负载量为0.85%的AC-Mg，在氨氮浓度为60mg/L，磷源浓度为60mg/L，温度为25℃条件下，反应2.5h，达到去除平衡。对氨氮的去除过程符合准二级动力学模型（R2＞0.98），氨氮的吸附受到表面扩散和内部扩散共同作用。吸附过程符合Langmuir模型（R2=0.9983），最大单位去除量为37.05mg/g，其中吸附去除为5.56 mg/g，结晶反应去除为31.49mg/g；该方法去除氨氮的最佳pH为9.0，对氨氮的去除率为54.57%。

Abstract:

Abstract: Active clay containing magnesium (AC-Mg) was prepared by composite modification with active clay as raw material. As an efficient adsorbent, AC-Mg reacted with low concentration ammonia nitrogen and phosphorus in simulated wastewater. BET, XRD, SEM, FTIR and particle size of the recovered products were analyzed by the modified active clay and reaction. The mechanism of low concentration ammonia nitrogen removal and recovery, the effect of reaction temperature and initial pH of solution on the effect were investigated. The results showed that the removal equilibrium was achieved under the conditions of ammonia nitrogen concentration of 60mg/L, phosphorus source concentration of 60mg/L and temperature of 25℃ for 2.5h. The removal process of ammonia nitrogen conforms to the quasi-second-order kinetic model (R2 > 0.98), and the adsorption of ammonia nitrogen is affected by both surface diffusion and internal diffusion. The adsorption process was in accordance with Langmuir model (R2=0.9983), and the maximum unit removal was 37.05mg/g, of which adsorption removal was 5.56 mg/g and crystallization reaction removal was 31.49mg/g. The optimal pH of this method is 9.0, and the removal rate of ammonia nitrogen is 54.57%.