改性沸石去除模拟二级出水中氨氮的实验研究

发布时间：2018-10-12 06:36

【摘要】：近几十年来,随着工业的迅速发展使得用水需求量不断增长。环境污染问题也致使我国淡水资源日益短缺,而同时大量含有氮磷元素的生活污水和工业废水进入了水体,出水中氨氮浓度达不到排放标准,严重影响了人们的健康水平和制约了经济的发展。沸石作为一种廉价的吸附剂,对氨氮具有较高的选择吸附性,天然斜发沸石的吸附能力有限,但通过改性处理能大大提高其对氨氮的去除能力。针对二级出水中氨氮浓度达不到一级B标排放标准(限值15mg/L)的废水中氨氮的去除,本文以天然沸石为原材料,筛分后得到粒径为60～80目,预处理后通过酸、碱、盐、高温煅烧及其两种联合处理等多种改性方法,选出了最佳改性沸石来进行去除模拟二级出水中氨氮的实验研究。本课题的主要研究内容包括改性实验、静态实验、动态实验和再生实验。得出以下结论：改性实验对斜发沸石进行了多种方式处理,包括：高温处理、氢氧化钠溶液处理、盐酸处理、氯化钠溶液处理、高温+氯化钠溶液处理、氯化钠溶液+高温处理,得到斜发沸石经60g/L NaCl溶液+400℃高温处理后去除模拟氨氮废水效果最佳。静态实验探讨了模拟氨氮废水浓度为15mg/L,60g/LNaCl盐溶液+400℃高温处理得到的最佳改性沸石条件下,沸石投加量、反应时间、温度、pH和起始氨氮浓度对氨氮去除效果的影响。在投加量为1.5g,反应时间为40min,温度为30℃,pH=8条件下,氨氮去除率达91.4%以上。吸附等温式模型既符合Langmuir方程式也符合Freundlich方程式,且对Freundlich方程拟合效果更好,相关系数R2大于0.98,且吸附反应为自发吸热的。吸附动力学模型对Langmuir一级动力学拟合方程拟合效果最好,其相关系数R2大于0.99。动态实验探讨了滤料层厚度、滤速对氨氮饱和穿透曲线的影响,结果表明滤料层厚度越高对应穿透时间越长,过滤速度越大对应的穿透时间越短。实验条件下,当滤料层厚度为80cm时,达到吸附穿透点时间为570min；当滤速为5mL/min时,达到吸附穿透点时间为690min。当滤柱内径为4cm时,改性沸石滤料层厚度为80cm,吸附柱滤速控制为5mL/min时,改性沸石滤柱去除模拟氨氮废水中氨氮的效果更好。说明用改性沸石滤柱处理氨氮废水是可行的、有效的。再生实验内容探究了NaCl再生液浓度、再生时间和再生次数对饱和改性沸石再生率的影响,结果表明NaCl再生溶液浓度为0.6mol/L,再生时间为2.5h时,饱和改性沸石的再生率达到84.5%以上。且在相同条件下,前八次再生处理均可使饱和改性沸石的吸附能力基本恢复在78%～85%,出水氨氮浓度均小于5mg/L,达到实验要求氨氮出水浓度,说明该种实验沸石再生能力较强,可以重复利用。
[Abstract]:In recent decades, with the rapid development of industry, the demand for water has been increasing. The problem of environmental pollution also causes the shortage of fresh water resources in our country. At the same time, a large number of domestic sewage and industrial wastewater containing nitrogen and phosphorus elements have entered into the water body, and the concentration of ammonia nitrogen in the effluent water is not up to the discharge standard. Has seriously affected the people's health level and restricted the economic development. As a cheap adsorbent, zeolite has high selective adsorption for ammonia nitrogen, and natural clinoptilolite has limited adsorption ability, but the removal capacity of ammonia nitrogen can be greatly improved by modification. Aimed at the removal of ammonia nitrogen in wastewater with ammonia nitrogen concentration below the first B standard (15mg/L), the natural zeolite was used as raw material and the particle size was 6080 mesh after sieving. After pretreatment, acid, alkali and salt were used. The optimum modified zeolite was selected to remove ammonia nitrogen from simulated secondary effluent by high temperature calcination and two kinds of combined treatment. The main research contents include modification experiment, static experiment, dynamic experiment and regeneration experiment. The conclusions are as follows: the modification experiment has carried on many ways to treat clinoptilolite, including: high temperature treatment, sodium hydroxide solution treatment, hydrochloric acid treatment, sodium chloride solution treatment, high temperature sodium chloride solution treatment, After high temperature treatment with sodium chloride solution, clinoptilolite was treated with 60g/L NaCl solution at 400 鈩，

本文编号：2265147