吸附—介电泳法去除水中氨氮的工艺及机理研究

发布时间：2018-06-20 05:43

本文选题：氨氮 + 吸附　；参考：《中央民族大学》2015年硕士论文

【摘要】：本研究将吸附法与介电泳技术相结合,建立了一种新型氨氮去除工艺并探究了其去除机理及运行条件。本研究主要分为四个方面：(1)在多种天然废弃物中筛选适宜吸附材料及其最佳制备条件研究；(2)吸附材料对水中氨氮的吸附性能及机理研究；(3)吸附-介电泳工艺条件与机理探究；(4)吸附-介电泳去除水中氨氮的中试放大装置设计与组装。在吸附材料筛选及制备研究中,主要得出三个重要结论：(1)通过测定氨氮去除效果,对14种天然废弃物进行吸附材料的筛选,确定炭化玉米芯为最佳吸附剂。(2)炭化玉米芯制备的条件探索实验表明,产率随着炭化温度的升高、炭化时间的延长均逐渐下降,炭化玉米芯比表面积随炭化温度升高而增大,在相同炭化温度下,炭化时间为30min时炭化玉米芯比表面积最大,不同炭化温度下制备的炭化玉米芯表面均存在含氧官能团。(3)通过炭化玉米芯产率、比表面积、形貌及红外光谱分析,尤其对氨氮去除效果进行评估,确定炭化玉米芯最佳制备条件为炭化温度为300℃,炭化时间为30min。深入研究了炭化玉米芯对氨氮吸附性能及机理。首先,通过考察吸附效果,确定了吸附工艺的最佳条件：炭化玉米芯投加量为10g/L,pH值6.77(不加酸碱调节),吸附平衡时间为360min。结论如下：(1)炭化玉米芯对氨氮的吸附动力学行为符合准二级吸附动力学模型及颗粒内扩散模型,吸附分为两个阶段：伴随外表面吸附的膜扩散控制阶段及内扩散阶段,过程中存在化学吸附。(2)吸附热力学行为符合Freundlich模型及D-R模型,吸附反应易于进行,物理和化学吸附共存。(3)热力学参数Gibbs自由能△G0,吸附焓△H0,熵AS0,该吸附过程为可自发进行的熵增吸热反应。(4)炭化玉米芯吸附氨氮前后SEM表征及红外光谱分析表明,吸附后炭化玉米芯整体粒径变小,表面变得较为粗糙,出现仲胺C-N键的伸缩振动和弯曲震动,表明存在氨氮吸附于炭化玉米芯表面。建立了吸附-介电泳处理氨氮废水的新方法,探索了工艺条件对去除效果的影响规律。首先,通过实验在三类电极中筛选了100目钛丝网电极为最佳电极,介电泳池构型为截流式时氨氮去除效果最好。主要得出以下结论：(1)吸附-介电泳处理后氨氮去除效果比单纯吸附的增量,随吸附时间延长均逐渐增大,确定吸附时间为360min。(2)吸附-介电泳处理后氨氮去除效果及其增量也随吸附剂投加量增大均逐渐增大,确定吸附剂投加量为10g/L。(3)吸附-介电泳处理时,氨氮去除率随电压升高逐渐增加,增至20V后去除率变化不大,悬浮液基本澄清,确定介电泳电压为20V。(4)氨氮去除率随着介电泳停留时间的延长而增大,考虑能耗,确定介电泳停留时间为30min,氨氮去除率提高了38.19%。(5)根据SEM表征结果,在介电泳处理过程中,吸附了氨氮的炭化玉米芯发生了介电捕获,结合介电泳技术后,氨氮去除率的提高可能是由于介电泳促进了氨氮在炭化玉米芯微粒表面的吸附。在中试装置设计及实验中,根据小试工艺实验结果,按照几何放大的方法设计计算吸附处理池、介电泳处理池构造及尺寸,使用AutoCAD软件绘制装置设计图。确定主材、辅料、加工方式以及入水、连接方式及电极放置连接方式。完成吸附-介电泳中试装置的组装,并在其中进行了吸附、吸附-介电泳中试实验。实验结果表明该中试装置可成功用于水中氨氮的去除。
[Abstract]:In this study, a new ammonia nitrogen removal process was established and the removal mechanism and operating conditions were explored by combining adsorption and dielectrophoresis. This study was divided into four aspects: (1) screening suitable adsorbents in a variety of natural wastes and the optimum preparation conditions; (2) adsorption properties of ammonia nitrogen in water. And mechanism research; (3) study on the conditions and mechanism of adsorption - dielectrophoresis; (4) the design and assembly of the pilot scale amplifier for removing ammonia nitrogen from water by adsorption electrophoresis. In the selection and preparation of adsorbents, three important conclusions are obtained: (1) screening for the adsorption materials of 14 natural wastes by determining the removal efficiency of ammonia nitrogen. It is determined that the carbonized corncob is the best adsorbent. (2) the conditions for the preparation of the carbonized corn core have shown that with the increase of carbonization temperature, the carbonization time prolongs gradually, and the specific surface area of the carbonized corn core increases with the increase of carbonization temperature. At the same carbonization temperature, the carbonized cob is the most specific surface area when the carbonization time is 30min. There are oxygen containing functional groups on the surface of carbonized corncob prepared at different carbonization temperatures. (3) through the carbonized corncob yield, specific surface area, morphology and infrared spectrum analysis, especially the effect of ammonia nitrogen removal, the optimum preparation conditions of the carbonized corn core are the carbonization temperature of 300, and carbonization time of 30min. to study the carbonization. First, the best conditions for the adsorption process were determined by the adsorption effect. The dosage of the cob was 10g/L, the pH value was 6.77 (without acid-base regulation), and the adsorption equilibrium time was 360min. as follows: (1) the adsorption kinetics of ammonia nitrogen by carbonized corn cob was in accordance with the quasi two adsorption kinetics Model and particle diffusion model, adsorption is divided into two stages: chemical adsorption in membrane diffusion and internal diffusion phase with external surface adsorption. (2) adsorption thermodynamic behavior conforms to Freundlich model and D-R model, adsorption reaction is easy to carry out, physical and chemical adsorption coexist. (3) thermodynamic parameter Gibbs free energy delta G0 The adsorption enthalpy Delta H0 and entropy AS0, the adsorption process is a spontaneous entropy increasing heat absorption reaction. (4) the SEM characterization and infrared spectrum analysis of the carbonized corncob before and after the adsorption of ammonia nitrogen shows that the overall particle size of the carbonized corncob is smaller and the surface becomes more rough after adsorption, and the expansion vibration and bending vibration of the secondary amine C-N bond show that the presence of ammonia nitrogen is adsorbed on carbon. A new method for the treatment of ammonia nitrogen wastewater by adsorption dielectrophoresis was established. The effect of process conditions on the removal efficiency was explored. First, 100 mesh titanium mesh electrodes were selected as the best electrode in three kinds of electrodes, and the effect of ammonia nitrogen removal was the best when the structure of dielectric swimming pool was intercepted. The following conclusions were drawn as follows: (1) After adsorption - dielectrophoresis, the removal efficiency of ammonia nitrogen was increased gradually with the increase of adsorption time. The adsorption time was 360min. (2) and the removal efficiency and increment of ammonia nitrogen were gradually increased with the increase of the dosage of adsorbents, and the dosage of adsorbents was 10g/L. (3) adsorption - electrophoresis treatment. The removal rate of ammonia nitrogen increased gradually with the increase of voltage, and the removal rate changed little after increasing to 20V. The suspension solution was basically clarified and the removal rate of the dielectric voltage was 20V. (4). The removal rate of ammonia nitrogen increased with the extension of the diphoretic residence time, considering the energy consumption, determining the residence time of 30min, and increasing the ammonia nitrogen removal rate by 38.19%. (5) according to the SEM characterization results. In the process of dielectric electrophoretic treatment, the dielectric capture of the carbonized corncob of ammonia nitrogen has been adsorbed. The increase of ammonia nitrogen removal rate may be due to the enhancement of the adsorption of ammonia nitrogen on the surface of the cob particles. In the design and experiment of the pilot plant, according to the geometric magnification side. The method is designed and calculated for the adsorption pool, the structure and size of the pool, and the design diagram of the device is drawn by AutoCAD software. The main material, the auxiliary material, the processing way and the way of water entry, connection and electrode placement are used. The assembly of the test device for the adsorption - dielectrophoresis is completed, and the adsorption, the adsorption - dielectrophoresis test experiment and the experiment are carried out. The results show that the pilot plant can be successfully applied to remove ammonia nitrogen in water.
【学位授予单位】：中央民族大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703

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