改性分级多孔炭对废水中染料吸附性能的研究

发布时间：2018-04-22 00:32

本文选题：染料废水 + 吸附　；参考：《安徽工业大学》2017年硕士论文

【摘要】：吸附法由于操作简单,能在温和条件下选择性脱除废水中的染料分子,其在染料废水治理中得到广泛应用。吸附剂是吸附技术的核心。本文以石油沥青为碳源、氧化锌为模板,KOH为活化剂,采用常规加热法制备分级多孔炭,并考察了其对亚甲基蓝、直接黑38染料的吸附性能。为了拓展其应用领域,对其表面进行了负载金属离子改性。为了提高多孔炭对酸性染料的吸附性能,对煤沥青基多孔炭表面进行嫁接聚酰胺胺(PAMAM)树状大分子改性,并研究其对酸性橙74、刚果红染料的吸附性能。通过氮气吸脱附、TEM、FESEM、XRD、XPS对分级多孔炭的物理结构和表面化学性质进行了表征,其主要结果如下:(1)以石油沥青为碳源,氧化锌为模板耦合KOH活化,制备出分级多孔炭(PCs)。结果表明;所制备的分级多孔炭具有相互连接的薄片状结构,且含有丰富的微孔和中孔。当石油沥青、氧化锌和KOH的质量分别为2,19和6 g,活化终温为850℃,制得的PC_(2-19-850)的比表面积高达1913 m2/g。对染料的吸附性能研究表明,由于存在大量的超级微孔,分级多孔炭对分子尺寸较小的亚甲基蓝表现出优异的吸附性能;同时分级多孔炭存在一定量的中孔,其对分子尺寸较大的直接黑38也具有一定的吸附性能。PC_(2-19-850)对亚甲基蓝染料的吸附等温线可以用Langmuir模型描述,最大吸附量可达887 mg/g,对直接黑38染料的吸附等温线可以用Freundlich模型来描述。动力学研究表明,拟二级动力学模型可以较好地描述多孔炭对亚甲基蓝的吸附行为,而拟一级动力学模型则可以描述多孔炭对直接黑38染料的吸附行为。(2)以PC_(2-19-850)为初始炭,对其表面负载金属离子,制备出改性多孔炭Zn(II)/PC和Fe(III)/PC。结果表明;经负载改性后的Zn(II)/PC和Fe(III)/PC依然含有微孔和中孔,但由于金属离子堵塞部分微孔导致其比表面积有不同程度下降。经负载金属离子后,其表面化学性质发生了明显变化,金属离子含量增大,含氧官能团增加。负载金属离子改性多孔炭对其染料吸附性能有重要影响,由于表面含有大量分散的Zn(II),Zn(Ⅱ)/PC表面形成新的吸附活性位,在较低浓度下,其对亚甲基蓝和直接黑38都表现出优异的吸附性能。由于比表面积剧烈下降,Fe(III)/PC对亚甲基蓝的吸附性能较初始炭降低了,但对于分子尺寸较大的直接黑38染料,其吸附性能却有了明显提高。动力学研究表明,拟二级动力学模型都可以描述改性多孔炭对亚甲基蓝和直接黑38染料的吸附行为。(3)以乙二胺、丙烯酸甲酯、甲醇为原料,采用”一锅法”制备2.0代的PAMAM。以MC2-19-850为初始炭,通过其表面的羧基与PAMAM发生氨基酰胺化反应,将PAMAM嫁接到分级多孔炭上制备新型复合炭材料PMC。结果表明;PMC依然含有微孔和中孔,但由于PAMAM的负载,导致复合炭的比表面积较初始炭有不同程度下降。对染料的吸附研究表明,调节溶液pH值,可改变PMC对酸性染料的吸附性能;中性条件下,由于PMC的比表面积比初始炭小,其对酸性橙74和刚果红染料的吸附性能低于初始炭。酸性条件下,PMC表面的PAMAM质子化,能和染料之间形成静电吸引作用,其对染料的吸附能力大幅提高,在很低的平衡浓度下,都能表现出极其优异的吸附性能。当pH值分别为4.4和2.3时,PMC对酸性橙74和刚果红染料的吸附性能达到最佳。PMC表面含N量越高,其对染料的吸附性能越高。所制备的复合炭可用于酸性染料的超深度脱除。
[Abstract]:Adsorption method can be used for selective removal of dye molecules in wastewater under mild conditions. It is widely used in the treatment of dye wastewater. Adsorbents are the core of adsorption technology. This paper takes petroleum asphalt as the carbon source, Zinc Oxide as a template and KOH as activator. The adsorption properties of methyl blue and Direct Black 38 dye were carried out. In order to expand its application field, metal ions were modified on its surface. In order to improve the adsorption properties of porous carbon to acid dyes, the grafting polyamines (PAMAM) tree like macromolecular modification on the surface of coal tar pitch carbon was carried out, and its effect on Acid Orange 74, Congo red dye was studied. The physical structure and surface chemical properties of the graded porous carbon were characterized by nitrogen adsorption and desorption, TEM, FESEM, XRD, XPS. The main results were as follows: (1) using petroleum asphalt as the carbon source, Zinc Oxide was activated by the template coupling KOH to prepare the graded porous carbon (PCs). The results showed that the prepared graded porous carbon was connected with each other. The mass of oil bitumen, Zinc Oxide and KOH are 2,19 and 6 g respectively, and the activation end temperature is 850 C, and the specific surface area of PC_ (2-19-850) is up to 1913 m2/g. to the dye adsorption properties. Methylene blue showed excellent adsorption properties; at the same time, the porous carbon had a certain amount of mesopore, which had a certain adsorption property for the Direct Black 38 with larger molecular size. The adsorption isotherm of the methylene blue dye could be described by Langmuir model, the maximum adsorption amount could reach 887 mg/g, and the adsorption of Direct Black 38 dye, and so on. The temperature line can be described by the Freundlich model. The kinetic study shows that the quasi two order kinetic model can describe the adsorption behavior of the methylene blue to the porous carbon well, and the pseudo first order kinetic model can describe the adsorption behavior of the porous carbon to the Direct Black 38 dye. (2) PC_ (2-19-850) is the initial carbon and the metal ions are loaded on the surface of the carbon. The results of the preparation of modified porous carbon Zn (II) /PC and Fe (III) /PC. showed that the Zn (II) /PC and Fe (III) /PC still contained micropores and mesopore, but the specific surface area of the micropores caused by metal ions blocked the surface area to varying degrees. After loading metal ions, the surface chemical properties of the metal ions changed obviously, the metal ion content was changed. Increased oxygen functional groups increased. The porous carbon loaded with metal ions has an important effect on the adsorption properties of the dyes. Because the surface contains a large number of dispersed Zn (II), the surface of Zn (II) /PC forms a new adsorption active site, and at a lower concentration, it exhibits excellent adsorption properties for methylene blue and Direct Black 38. The adsorption performance of Fe (III) /PC on methylene blue decreased compared with the initial carbon, but the adsorption performance of the Direct Black 38 dye with larger molecular size has been obviously improved. The kinetic study shows that the pseudo two kinetic model can describe the adsorption behavior of modified porous carbon to methylene blue and Direct Black 38 dye. (3) ethylene diamine, C Methyl enate and methanol were used as raw materials. The 2 generation of PAMAM. was prepared by one pot method, and MC2-19-850 was used as initial carbon. Through the carboxyl group on its surface and amidoylation of PAMAM, PAMAM was grafted onto graded porous carbon to prepare a new type of composite carbon material PMC. results. PMC still contained micropores and mesopore, but due to PAMAM load. The specific surface area of the composite carbon decreased in varying degrees than that of the initial carbon. The study on the adsorption of dyes showed that the pH value of the solution could change the adsorption properties of the acid dyes by PMC; under the neutral condition, the adsorption property of the acid orange 74 and the Congo red dye was lower than the initial carbon. Under the acidic condition, the surface of PMC was lower than the initial carbon. The PAMAM protonation can form the electrostatic attraction between the dye and the dye, and the adsorption capacity of the dye is greatly improved. At a very low equilibrium concentration, it can all show excellent adsorption properties. When the pH value is 4.4 and 2.3, the adsorption property of PMC to the acid orange 74 and the Congo red dye is higher than that of the best.PMC surface. The adsorption capacity of the material is higher. The prepared composite carbon can be used for ultra deep removal of acid dyes.

【学位授予单位】：安徽工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ424;X788

【参考文献】