温度敏感吸附材料制备及去除水中酚类污染物效能研究

发布时间：2018-03-07 12:30

  本文选题：原子转移自由基聚合　切入点：酚类污染物　出处：《哈尔滨工业大学》2017年博士论文　论文类型：学位论文

【摘要】：近年来酚类污染物对水体的污染日趋严重,吸附技术尤其是使用活性炭的吸附技术已经成为去除水中有机污染物最为有效和广泛的方法,然而吸附性能较好的粉末活性炭(PAC)、石墨烯等材料往往粒度较小,应用于水处理后难以分离回收,因此提升此类材料的分离回收能力具有重要的实践意义。本文选用多孔材料粉末活性炭和片状材料氧化石墨烯(GO)和氮化硼(BN),对其进行接枝聚(N-异丙基丙烯酰胺)(PNIPAM)改性,研究改性吸附材料具有的独特温度敏感絮凝性能和对特征酚类污染物双酚A、苯酚和对苯二酚的吸附性能和脱附能力,为自絮凝材料应用于吸附酚类污染物领域的研究提供理论基础。分别采用酸化改性和氧化改性的方法对活性炭表面进行前处理,在此基础上对活性炭表面改姓,采用原子转移自由基聚合的(ATRP)方法在改性活性炭表面接枝PNIPAM,通过傅里叶红外光谱(FT-IR)、扫描电子显微镜(SEM)、热重分析(TGA)、X-射线光电子能谱(XPS)对不同改性方法、不同接枝量的接枝产物的热稳定性、表面结构和成分进行了表征和检测。采用相似的合成工艺,分别在氧化石墨烯和片状氮化硼表面接枝了PNIPAM,并对接枝产物的结构和成分进行了表征。分别对常温下接枝PNIPAM的活性炭、氧化石墨烯和氮化硼材料在水中的粒度和分散性能进行考察,表明接枝改性后,吸附材料的分散性能明显优化。在低浓度下(0.1 mg/L),考察接枝PNIPAM的吸附材料在最低临界相容温度(LCST)的粒度收缩效应,以此研究接枝的PNIPAM的微观链段变化。在较高浓度范围内(0.01 g/L-10 g/L),通过浑浊度分析及定量计算,考察因为PNIPAM的链段收缩和亲疏水相转变,而产生的接枝吸附材料的自絮凝效应。结果表明,在0.01 g/L-10g/L的浓度范围内,接枝改姓的材料随温度升高产生明显的自絮凝沉降现象,高浓度下去除率大于95%。在此基础上,分别研究了前处理方法、接枝PNIPAM的密度、不同材料基体对自絮凝性能的影响。选用内分泌干扰物双酚A(BPA)作为特征污染物,通过考察目标物吸附能力与改性活性炭比表面积和表面性质关系这一关键问题,详细地研究了BPA在各类改性活性炭表面的吸附行为,讨论了不同的前处理方法,以及接枝PNIPAM量对BPA吸附性能的影响。表明可以选用酸化或酸化氧化改性活性炭的工艺,并控制PNIPAM的接枝量,制备出对BPA吸附能力较强的PAC-PNIPAM,吸附容量可以达到247.5 mg/g。机理分析表明,BPA在接枝改性活性炭上的吸附主要来源于π-π色散作用和氢键作用,其中传统的π-π色散作用依然处于主导地位。选出一种接枝PNIPAM的活性炭,探讨了影响BPA吸附的环境因素。同时考察了在临界相容温度时,PNIPAM链段变化对吸附饱和的接枝活性炭脱附性能的影响,进而研究接枝改性活性炭的再生性能。确定可以在温水中(温度高于最低临界相容温度),使用超声再生的方式实现接枝改性的粉末炭再生,3次再生后仍然保留75%以上的吸附性能。制备表面接枝PNIPAM的氧化石墨烯和氮化硼材料,对接枝前后的两种片状材料的比表面积进行分析,表明接枝后可明显促进片状材料的分散和比表面积的提升。之后重点考察两种接枝改性的片状材料分别对双酚A、苯酚和对苯二酚的吸附性能,表明接枝PNIPAM的材料对酚类污染物有选择性吸附能力。以接枝PNIPAM的氧化石墨烯为例,对其选择性吸附的机理进行了研究。同时研究了在临界相容温度时,对苯二酚在接枝改性氧化石墨烯材料上吸附性能的变化,并与吸附机理进行印证,表明接枝PNIPAM的材料对于小尺寸亲水酚类污染物的选择性吸附能力。最后对温水中接枝改姓石墨烯的脱附回用能力进行了研究。
[Abstract]:In recent years, the pollution of phenolic pollutants in water is becoming more and more serious, especially the adsorption technology using activated carbon adsorption technology has become the most effective for the removal of organic pollutants in water and a wide range of methods, however, the adsorption of powdered activated carbon (PAC), the better performance of graphene materials to smaller particle size, used in water treatment is difficult to separate recovery, so to enhance the ability of separation and recovery of these materials has important practical significance. This paper selects the porous materials of powder activated carbon and graphite oxide graphene sheet material (GO) and boron nitride (BN), the grafted poly (N- isopropylacrylamide) (PNIPAM) modification, modification of temperature sensitive flocculation performance is unique adsorption materials and characteristics of phenolic pollutants bisphenol A, adsorption of phenol and hydroquinone and desorption ability, provide a theoretical study of self flocculating material applied to the adsorption of phenolic pollutants in the field On the basis of. The surface of the activated carbon was pretreated by acidification method modification and oxidation modification, on the basis of the surface modification of activated carbon by atom transfer radical polymerization (ATRP) method on modified activated carbon surface grafted PNIPAM by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X- ray photoelectron spectroscopy (XPS) of different modification methods, the thermal stability of the grafted product of different grafting amount, surface structure and composition were characterized and detected by synthesis of similar, respectively in graphene oxide and boron nitride sheet surface grafting of PNIPAM. And the structure and composition of the grafted products were characterized respectively. Activated carbon on room temperature grafting PNIPAM, graphene oxide and boron nitride materials were investigated in the water particle size and dispersion properties, show that the modified dispersion, adsorption materials The performance was optimized. At low concentration (0.1 mg/L), on grafting of PNIPAM adsorbent at lower critical solution temperature (LCST) size contraction effect, in order to study the grafted PNIPAM micro segment changes. At higher concentration range (0.01 g/L-10 g/L), using the turbidity analysis and quantitative calculation, because of the PNIPAM chain segment contraction and hydrophobic phase transition, self flocculating effect of graft materials resulting from the adsorption. The results showed that in the concentration range of 0.01 g/L-10g/L, the graft material with the increase of temperature has changed significantly since the flocculation phenomenon, high concentration on removal rate of more than 95%. on the basis of this, the pretreatment method study of PNIPAM grafting density, effect of different material matrix on the self flocculating performance. Using bisphenol A (BPA) as the characteristic pollutants, through the investigation of the target and the adsorption capacity of modified activated carbon surface The key problem of the area and surface properties, a detailed study of the adsorption behavior of BPA on all kinds of surface modification of activated carbon, discusses different pretreatment methods, effects on Adsorption Properties of BPA and PNIPAM grafted amount. Indicate that the process can be selected or acidification acidification oxidation modification of activated carbon, the grafting amount and control PNIPAM the preparation of BPA PAC-PNIPAM adsorption ability, the adsorption capacity can reach 247.5 mg/g. analysis showed that the adsorption of BPA on modified activated carbon mainly originates from the Pi Pi dispersion interaction and hydrogen bonding interaction, in which the traditional Pi Pi dispersion effect is still in a dominant position. Select a graft of activated carbon PNIPAM, to explore the factors influencing the adsorption of BPA environment. At the same time on the critical solution temperature, effect of PNIPAM segment change desorption performance of the grafted activated carbon adsorption saturation, and then study the grafting modification The regeneration performance of activated carbon can be determined. In warm water (temperature above the lower critical solution temperature), carbon powder with ultrasonic regeneration method of graft modified regeneration after 3 times regeneration still retain the adsorption performance of more than 75%. The preparation of PNIPAM grafted onto the surface of graphene oxide and boron nitride materials, two kinds of sheet the material of the grafted surface area analysis showed that grafting can obviously promote the dispersion of sheet material and surface area increase. After focusing on two kinds of sheet material grafted respectively on bisphenol A, adsorption of phenol and hydroquinone, PNIPAM showed that the graft material has selective adsorption ability of phenolic pollutants in graphene oxide grafted PNIPAM as an example, the mechanism of selective adsorption was studied. At the same time in the study of the critical solution temperature, hydroquinone in graft modification of graphene oxide material Adsorption properties of the material, and were verified with the adsorption mechanism, PNIPAM showed that the graft material for selective adsorption ability of hydrophilic phenolic pollutants in small size. At the end of the warm water in the grafted graphene surname desorption and reuse ability were studied.

【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：X52
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本文编号：1579307