石墨烯基材料对水中消毒副产物及新兴有机微污染物的去除研究

发布时间：2018-01-02 12:21

本文关键词：石墨烯基材料对水中消毒副产物及新兴有机微污染物的去除研究　出处：《东北师范大学》2017年博士论文　论文类型：学位论文

【摘要】：经传统工艺处理后的饮用水中含有众多消毒副产物(DBPs),且由于人们生产生活的大量排放,新兴有机微污染物(OMPs)在地表水中被频繁检出,这些污染物已经对人类健康造成了长期不良影响,所以急需探索和研究新的水处理材料和工艺对水体进行深度净化。本论文成功制备4种功能化石墨烯基材料,并将其应用到水体净化中,研究对DBPs及OMPs的去除效率和机制。首先,采用氧化石墨烯(GO)对水中卤乙酸(HAAs)进行终端去除。利用GO分子表面含有的丰富含氧官能团,通过与HAAs分子间产生的氢键作用使其快速吸附去除。结果表明,在2 min内HAAs的去除效率可以达到30%左右。随着pH的增加,HAAs的去除效率逐渐减小。温度变化对HAAs的去除不起决定作用,仅影响分子间氢键作用的速率。因分子间氢键作用是较弱的作用力,且水流剪切力破坏氢键作用,所以采用连续吸附程序对HAAs进行多次去除。经连续5次吸附后,HAAs的去除效率可以达到88%,且总耗时仅为2.25 min。为避免吸附剂流失对水体造成二次污染,本研究对GO进行改进制备得到可磁回收再利用的磁性氧化石墨烯(MGO)。MGO对地表水中DBPs前体物具有较强的吸附去除作用。经MGO处理后的4份地表水样中DBPs前体物的去除效率从7~19%增加到78~98%,且处理程序在20 min内快速达到平衡状态。随pH值从4增加到10,DBPs前体物的去除效率逐渐减小。MGO对疏水化合物(腐殖酸和富里酸)更加敏感,而对亲水性和含氮类化合物(芳香族蛋白质)不敏感。MGO可以通过使用20%(v/v)的乙醇进行再生,且在5次循环利用后DBPs前体物的去除效率能够保持稳定。本研究进一步对常见石墨烯基材料进行优化,制备得到具有较大比表面积的磁性多孔石墨烯(MPG)。实验以个人护理品中广泛使用的广谱抗菌剂三氯生(TCS)作为OMPs代表,通过静态吸附实验发现MPG优于石英砂、石墨烯、GAC、PAC和MGO等吸附剂,对TCS的去除效率可以达到98%,且吸附过程符合准二级动力学。臭氧预氧化能有效去除TCS,但会产生以2,4-二氯苯酚为主的氧化副产物。本论文进一步提出MPG和臭氧氧化联合处理工艺(MPG+O3),经MPG短时吸附后进行臭氧氧化,能实现TCS的完全去除和氧化副产物的最小化。相比于预臭氧联合MPG吸附工艺(O3+MPG),MPG+O3具有总耗时和臭氧消耗量少等特点,且能够有效去除TCS,并有效控制中间副产物和DBPs的生成。MPG经简单再生后,仍然保持有对TCS的去除活性。此外,由于具有较大比表面积和丰富的孔结构,MPG对12种目标OMPs具有很好的去除效果。为达到滤料的易填装和不易流失等目的,本论文制备得到具有整体稳定性的三维石墨烯(3DG),并采用3DG介质填充柱模拟固定床工艺净化自来水。随着空床接触时间(EBCT)的增加,水中UV254、浊度和余氯等基本指标的去除效率在不断增加,卤代挥发类DBPs的去除效率也有不同程度的增加。相反,HAAs的去除效率则不断减小。通过灵活控制滤床的EBCT可以有效去除水中不同种类的DBPs。相比于3DG,3DG-石英砂混合滤床显著减小了设备的成本,且对浊度、余氯及多种DBPs的去除效率有明显增大趋势。采用3DG-石英砂固定床过滤对含有12种OMPs水体进行连续净化,发现3DG对疏水性、大分子化合物具有较好的去除能力,又因大分子抢先占据孔道的吸附点位从而发生竞争吸附现象,所以小分子化合物不易被3DG去除。随着EBCT的增加,3DG-石英砂过滤对OMPs的去除效率也随之增加。综上所述,石墨烯基材料对于去除水中DBPs及OMPs来说是一种具有应用前景的吸附剂。
[Abstract]:The traditional process of drinking water containing numerous disinfection by-products (DBPs), and due to the large number of people's life and production emissions, emerging micro organic pollutants (OMPs) are frequently detected in surface water, these pollutants have caused long-term adverse effects on human health, so there is an urgent need to explore and research new material and technology of water treatment on the water for purification. This paper successfully prepared 4 kinds of functionalized graphene based materials, and its application to water purification, research on DBPs and OMPs removal efficiency and mechanism. Firstly, using graphene oxide (GO) of haloacetic acids in water (HAAs) terminal using GO molecule with removal. The surface of rich oxygen containing functional groups, hydrogen bonding interactions between HAAs molecules and produced by the rapid adsorption. The results showed that HAAs within 2 min removal efficiency can reach about 30%. With the increase of pH, the removal of HAAs The efficiency decreases gradually. The temperature change on the removal of HAAs does not play a decisive role, only affects the rate of intermolecular hydrogen bonding interactions. Because the intermolecular interaction is weak force and shear stress damage of hydrogen bonding, so the use of HAAs for removal of multiple continuous adsorption procedure. After 5 consecutive adsorption, the removal efficiency of HAAs can reach 88%, and the total time is only 2.25 min. in order to avoid the loss of adsorbent cause two pollution to water, improve the prepared magnetic graphene oxide magnetic recycling of GO (MGO).MGO has the function of removing the strong adsorption of surface water DBPs precursors by DBPs 4. Surface water samples after treatment with MGO in the precursor removal efficiency increased from 7~19% to 78~98%, and the processing program quickly reach equilibrium at 20 min. With the pH value increased from 4 to 10, the removal efficiency of DBPs precursors of.MGO decreased gradually Hydrophobic compounds (humic acid and fulvic acid) are more sensitive, while the hydrophilic and nitrogen compounds (aromatic protein) is not sensitive to.MGO (v/v) by using 20% ethanol for regeneration, can keep stable and the removal efficiency of 5 cycles after using DBPs precursors. The common graphite vinyl materials were optimized in this study, prepared with larger magnetic porous Shi Moxi surface area (MPG) is widely used in the experiment. A broad spectrum of personal care products in three antibacterial agent triclosan (TCS) as the representative of OMPs, the static adsorption experiment found that MPG is better than that of quartz sand, graphite, GAC, PAC and MGO such as adsorbent, the TCS removal efficiency can reach 98%, and the adsorption process accords with the quasi two level dynamics. Ozone pre oxidation can effectively remove TCS, but will produce oxidation by-products to two 2,4- chlorine phenol. This paper further proposed MPG and ozone oxidation combined Combined treatment process (MPG+O3), the MPG short time after adsorption of ozone oxidation, minimization can achieve TCS complete removal and oxidation by-products. Compared to the pre ozonation combined with MPG adsorption process (O3+MPG), MPG+O3 has the total time and ozone consumption characteristics of less weight, and can effectively remove the TCS, and effectively control the middle side and the product of DBPs.MPG generated by simple regeneration after removal remains on the activity of TCS. In addition, due to their large surface area and abundant pore structure, MPG has a good removal effect on 12 kinds of target OMPs. In order to filter easily filling and not easy to drain to the preparation three-dimensional graphene has the overall stability (3DG), and using 3DG medium filling column simulated fixed bed process for purification of tap water. With the empty bed contact time (EBCT) increased, UV254 in water, chlorine and other basic indicators and turbidity removal efficiency in time Halogenated volatile DBPs increased, the removal efficiency will increase to some extent. On the contrary, the removal efficiency of HAAs decreased gradually. The effective removal of different types of DBPs. in water compared to 3DG can flexibly control the filter bed EBCT, 3DG- mixed quartz sand filter bed significantly reduces the cost of the equipment, and the removal of turbidity. The efficiency of residual chlorine and a variety of DBPs increases significantly. By using the 3DG- fixed bed quartz sand filter continuous purification with 12 kinds of OMPs water, 3DG of hydrophobic macromolecules has better removal ability, and because the big molecules take according to adsorption point pore to the competitive adsorption phenomenon, so small molecules 3DG compound is not easy to be removed. With the increase of EBCT, the removal efficiency of 3DG- quartz sand filtration for OMPs also increased. In summary, graphene based materials is a kind of water for the removal of DBPs and OMPs Applied adsorbents.

【学位授予单位】：东北师范大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TQ424;TU991.2

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