改性生物砂滤工艺对城市污水厂尾水中典型PhACs的去除机理研究

发布时间：2018-02-24 12:46

本文关键词： PhACs 改性石英砂吸附影响因素表征　出处：《河北工程大学》2017年硕士论文　论文类型：学位论文

【摘要】：由于人类对医药活性物质(Pharmaceutically Active Compounds,PhACs)的过分使用甚至是滥用,导致这类化合物及其代谢产物被持续不断地排入地表水、地下水及土壤等各种环境介质中,PhACs在环境中的迁移、转化、生态毒理及其控制处理已成为环境科技界日益关注的热点问题。而在我国,还鲜有此方面的研究报道。而且我国70%以上的污水处理厂并没有针对PhACs建设专门的去除工艺(或工段)。因此,有必要研究新型的深度处理工艺来去除PhACs,以降低PhACs对水环境造成的污染。本试验研究,以Piranha溶液、KH-550水解液以及铁盐作为改性剂对石英砂滤料进行改性,改性后的石英砂其表面变得凹凸不平,通过扫描电镜(SEM)、X射线衍射、红外光谱和有机碳含量分析对改性前后的石英砂滤料进行表面结构表征。基于吸附动力学试验及等温吸附平衡试验考察了普通、亲水改性、疏水改性和铁离子改性(生物)石英砂对PhACs的吸附过程;研究了石英砂改性前后以及生物覆膜前后对PhACs吸附性能的影响;分析了其吸附机理以及微生物在生物覆膜石英砂去除PhACs中的贡献率。研究结果表明:(1)以Piranha溶液、KH-550水解液以及铁盐作为改性剂对粒径为1.0mm~1.7mm的石英砂进行改性,得到亲水改性、疏水改性和铁离子改性这三种改性石英砂。本试验选用四环素、环丙沙星及美托洛尔作为研究对象。经过Piranha溶液处理后,石英砂表面的杂质被氧化处理后呈现网状立体结构,比表面积增大,因此亲水改性石英砂对PhACs的吸附去除效果最好;与普通石英砂相比,疏水改性和铁离子改性石英砂对所选用的三种PhACs的去除效果有不同程度的下降。(2)基于吸附动力学试验结果,可发现改性石英砂和生物覆膜石英砂对PhACs的静态吸附均在2h内基本达到平衡,改性石英砂及生物覆膜石英砂对PhACs的静态吸附过程均符合伪一级动力学模型,其主要吸附机制均为表面物理吸附。(3)基于等温吸附平衡试验结果,可发现当试验温度在288.15 K~309.15 K之间变化时,Langmuir等温吸附模型能更好地描述试验所得改性石英砂及生物覆膜石英砂对TCN、CIP和MTP的静态等温吸附行为。温度越接近298.15 K,改性石英砂以及生物覆膜石英砂对PhACs的静态吸附量越大。当pH在2.0~12.0的范围内变化时,美托洛尔的静态吸附效果不受pH值的影响,但强酸环境有利于四环素和环丙沙星的静态吸附,由此推断改性石英砂和生物覆膜石英砂对四环素和环丙沙星的主要吸附机制是阳离子吸附,对美托洛尔的主要吸附机理则是表面吸附。在PhACs溶液中分别加入K+、Na+和Ca2+时,其吸附效果均有不同程度的降低,其中Ca2+的抑制效果明显高于K+和Na+。(4)基于电镜扫描结果,可发现生物覆膜石英砂表面所附球菌、短杆菌、长杆菌以及节杆菌等与胞外聚合物共同形成了多孔且结构复杂的生物膜,此类生物膜对PhACs的削减具有明显的强化作用;通过序批试验研究,发现覆膜石英砂对PhACs的削减包含滤料吸附、微生物吸附及微生物降解三个途径,各途径贡献率随药物的品种不同而表现出明显差异,如除疏水改性、铁离子改性和普通生物覆膜石英砂对环丙沙星的降解率高于40%外;其余生物覆膜石英砂对PhACs的降解率仅在0~9.84%之间。
[Abstract]:Because of human pharmaceutical active substances (Pharmaceutically Active Compounds, PhACs) the excessive use and even abused, resulting in such compounds and their metabolites is continuously discharged into surface water, groundwater and soil environment, PhACs migration and transformation in the environment, ecological toxicology and control processing has become a hot issue of growing concern environmental science and technology circles. But in China, few studies of this report. And the sewage treatment plant in China more than 70% and not for removal of specialized PhACs construction (or section). Because of this, it is necessary to study the removal of PhACs advanced treatment process model, in order to reduce the PhACs of water environment pollution. This experiment, using Piranha solution, KH-550 hydrolysate and ferric salt as the quartz sand modifier, modified quartz sand the surface becomes uneven, through Scanning electron microscopy (SEM), X ray diffraction, the surface characterization of the modified quartz sand filter before and after the analysis of infrared spectrum and organic carbon content. The adsorption kinetics and isothermal adsorption equilibrium were investigated based on common, hydrophilic, hydrophobic modification and iron ion modified (bio) adsorption process of quartz sand of PhACs the study on the quartz sand; before and after modification and effect of biological film before and after the adsorption of PhACs on the analysis; the adsorption mechanism and microorganisms in biological removal of PhACs coated quartz sand in the contribution rate. The results show that: (1) to Piranha solution, KH-550 hydrolysate and ferric salt as a modifier of the particle size of 1.0mm~1.7mm the quartz sand was modified by hydrophilic and hydrophobic modification and iron ion modification of these three kinds of modified quartz sand. The tetracycline, ciprofloxacin and metoprolol as the research object. Through the Piranha solution After treatment, the surface impurities of quartz sand by oxidation treatment showed mesh structure, specific surface area increases, so the hydrophilic modification of quartz sand on the adsorption of PhACs had the best removal effect; compared with the ordinary quartz sand, hydrophobic modification and iron ion modified quartz sand for three PhACs the removal effect decreased different degree. (2) the results of adsorption kinetics can be found based on the modified quartz sand and bio coated quartz sand of PhACs static adsorption were basically reached equilibrium in 2H process, the static adsorption of PhACs on modified quartz sand coated quartz sand and biological are in line with the pseudo first order kinetic model, the adsorption mechanism are the physical surface adsorption isotherm. (3) based on the experimental results can be found when the test temperature changes between 288.15 K~309.15 K, Langmuir isotherm model can better describe the test of the modified quartz sand and The biological behavior of TCN coated quartz sand, static adsorption CIP and MTP. The temperature is close to 298.15 K, modified quartz sand coated quartz sand and biological adsorption capacity of PhACs increases. When the pH changes in the range of 2.0~12.0, effects of static adsorption of metoprolol was not affected by pH value, but the strong acid environment is the static adsorption to tetracycline and ciprofloxacin, concluded that the modified quartz sand coated quartz sand and biological adsorption mechanism mainly to tetracycline and ciprofloxacin is the main mechanism of cation adsorption, adsorption of metoprolol is adsorbed on the surface. K+ were added in PhACs solution, Na+ and Ca2+, reduce the adsorption effect in varying degrees among them, the inhibitory effect of Ca2+ was significantly higher than that of K+ and Na+. (4) based on the results of scanning electron microscope, can be found in bio coated quartz sand surface of coccus, Bacillus brevis and Bacillus coli, long day and cell Polymer together form the biofilm structure and complex porous, the biofilm has obvious effect on the strength of PhACs cut; by batch experiments, found that the coated quartz sand on the PhACs cut filter contains microbial adsorption, adsorption and microbial degradation of three ways, the way of contribution rate of different varieties with drugs significant differences, such as hydrophobic modification, iron ion modification and biological degradation of ciprofloxacin coated quartz sand rate is higher than 40%; the remaining bio coated quartz sand on the degradation rate of PhACs is only 0~9.84%.

【学位授予单位】：河北工程大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703

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