吸附-磷酸铵镁结晶耦合法去除低浓度氨氮  

Low concentration ammonia nitrogen removal via adsorption-struvite crystallization coupling method

作　　者：黄高鑫 唐玉朝[1] 伍昌年[1] 刘俊 宋永莲 HUANG Gaoxin;TANG Yuchao;WU Changnian;LIU Jun;SONG Yonglian(Anhui Key Laboratory of Water Pollution Control and Wastewater Recycling,Anhui Jianzhu University,Hefei 230601,Annui,China;Anhui Zhonghuan Environmental Protection Technology Co.,Ltd.,Hefei 230001,Annui,China)

机构地区：[1]安徽建筑大学水污染控制与废水资源化安徽省重点实验室,安徽合肥230601 [2]安徽中环环保科技股份有限公司,安徽合肥230001

出　　处：《精细化工》2022年第7期1464-1472,1512,共10页Fine Chemicals

基　　金：国家自然科学基金(51978003,51578002);安徽省高校自然科学研究重大项目(NO.KJ2019ZD54)。

摘　　要：以活性白土(AC)、氯化镁和氢氧化钠为原料,通过复合改性制得载镁活性白土(AC-Mg),将其作为高效吸附剂,并与模拟污水中的低浓度氨氮和磷发生磷酸铵镁结晶反应。对改性活性白土和反应后的回收产物采用BET、XRD、SEM、FTIR和激光粒度分析仪进行了表征。探究了吸附-磷酸铵镁结晶耦合法对低浓度氨氮去除和回收的机理,考察了磷源质量浓度、反应温度和溶液初始pH对氨氮去除效果的影响。结果表明,氧化镁负载量为0.85%的AC-Mg(以改性活性白土复合材料的质量为基准,下同),在氨氮质量浓度为60 mg/L,AC-Mg投加量为5 g/L,磷源质量浓度为60 mg/L,温度为25℃,pH为9.0条件下,反应2.5 h可达到去除平衡,AC-Mg对氨氮的去除量为6.79 mg/g,去除率为56.58%。AC-Mg对氨氮的去除过程符合准二级动力学模型(R^(2)>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(R^(2)=0.9923),氨氮最大去除量为37.05 mg/g。其中,吸附去除量为5.56 mg/g,磷酸铵镁结晶反应去除量为31.49 mg/g。Active clay loaded with magnesium(AC-Mg)was prepared by composite modification using active clay(AC),magnesium chloride and sodium hydroxide as raw materials,and then used as an efficient adsorbent to remove low concentration ammonia nitrogen and phosphorus by magnesium ammonium phosphate precipitation in simulated sewage.The AC-Mg obtained and products recovered from simulated sewage were characterized by BET,XRD,SEM,FTIR and laser particle size analyzer,followed by exploration on the mechanism of low concentration ammonia nitrogen removal and recovery by adsorptionmagnesium ammonium phosphate crystallization coupling method with the effects of mass concentration of phosphorus source,reaction temperature and initial pH of solution on ammonia nitrogen removal investigated.The results showed that the removal equilibrium could be achieved under the conditions of AC-Mg magnesium oxide loading(based on the mass of modified active clay composite,the same below)0.85%,ammonia nitrogen mass concentration 60 mg/L,AC-Mg dosage 5 g/L,phosphorus source mass concentration 60 mg/L,temperature 25℃,pH 9.0,and reaction time 2.5 h with ammonia nitrogen removal capacity by AC-Mg 6.79 mg/g,and the removal rate 56.58%.The removal process of ammonia nitrogen by AC-Mg conformed to the quasi-second-order kinetic model(R^(2)>0.98),and the adsorption of ammonia nitrogen was influenced by both surface and internal diffusion.The adsorption process was in accordance with Langmuir model(R^(2)=0.9923),and the maximum ammonia nitrogen removal was 37.05 mg/g,of which adsorption removal rate was 5.56 mg/g and the removal by magnesium ammonium phosphate crystallization reaction was 31.49 mg/g.

关 键 词：活性白土 磷酸铵镁 复合改性 反应动力学 吸附等温线 水处理技术 

分 类 号：X703[环境科学与工程—环境工程]