【作者】 高美娟；

【导师】 韩权；

【作者基本信息】 延安大学 ， 分析化学， 2011， 硕士

【摘要】 印染废水一般很难直接进行降解,直接排放会给环境带来很大危害。纳米材料吸附作为一种处理印染废水的新方法日益得到关注。功能化的磁性Fe₃O₄纳米材料具有强的磁响应性,应用于印染废水处理中,使其易于分离和回收,是一种理想的吸附剂。本研究的目的就是以功能化磁性纳米微球为吸附剂,着重探讨其对染料的吸附性能。依据上述目的,本研究主要包括以下几个方面:1.以FeCl₃·6H₂O和FeSO₄·7H₂O为原料,NH3·H₂O为沉淀剂,采用化学共沉淀法制备得到粒径约为15 nm的Fe₃O₄磁性微球。研究了铁盐物料比例、晶化温度、反应pH和碱源的选择等条件对所合成Fe₃O₄磁性微球性能的影响,并利用TEM、XRD、VSM、TGA、FT-IR等对其进行表征。结果表明:Fe₃O₄磁性粒子为尖晶石结构,热稳定性和磁响应性较好,饱和磁强度可达62.78 emu·g^-1。2.在磁性Fe₃O₄粒子的存在下,合成两种功能化修饰的磁性Fe₃O₄微球。采用3-氨丙基三乙氧基硅烷（APTES）对Fe₃O₄磁性微球进行硅烷化修饰,使其末端具有丰富的-NH₂,在经过酰胺化反应,得到末端含有丰富的-COOH的磁性微球。采用TEM、XRD、VSM、TGA、FT-IR等手段对合成的磁性材料进行了性能表征。结果表明:-NH₂和-COOH官能基团已经成功修饰到Fe₃O₄表面,修饰后的磁性微球保持了Fe₃O₄的尖晶石结构,饱和磁化强度有所下降,分别为56.98 emu·g^-1和53.63 emu·g^-1,但是在磁场中仍可以实现很好的固液分离,对下一步的染料吸附没有造成不良影响。3.以亚甲基蓝（MB）和乙基紫（EV）模拟印染废水,研究了氨基功能化磁性微球对其的吸附行为。以中性红（NR）和甲基橙（MO）模拟印染废水研究了羧基功能化磁性微球的吸附行为,并且考察了pH、染料初始浓度、吸附时间、离子强度和吸附温度等因素对吸附性能的影响,最后研究了磁性微球的重复利用。实验结果表明:1)氨基功能化磁性微球对MB的吸附受pH的影响较大;45 min内吸附基本达到平衡,实验数据可用准二级速率方程进行拟合;吸附为吸热过程,在298-333 K时,焓变△H为3.77 kJ/mol;等温吸附曲线可用Langmuir等温模型表示,饱和吸附量qm为70.42 mg/g,吸附平衡常数K为0.2160 L/mg。氨基功能化磁性微球对EV的吸附在pH为9.5时,吸附效果最佳;随着浓度的增加,吸附量增大;吸附为吸热过程,在298-328 K内,焓变△H为3.54 kJ/mol,且饱和吸附容量qm为29.06 mg/g,升高温度有利于吸附进行。2)羧基功能化磁性微球对NR的吸附在pH为4.5时,吸附量最大;15 min内吸附基本达到平衡;在一定的浓度范围内,离子强度对吸附量没有影响;吸附为吸热过程,在298-333 K内,焓变△H为4.10 kJ/mol;等温吸附曲线符合Langmuir模型,饱和吸附量qm为32.48 mg/g,吸附平衡常数K为0.0247 L/mg。羧基磁性微球对MO的最佳吸附浓度C0为80 mg/L;吸附为吸热过程,在298-323K内,焓变为△H为3.84 kJ/mol;等温吸附曲线符合Langmuir模型,饱和吸附量qm为56.82 mg/g,吸附平衡常数K为0.1107 L/mg。更多还原

【Abstract】 Generally, dyeing wastewater is difficult to degradate directly and it is harm to discharge. As a new processing method, nanomaterials have been paid more and more attention. Due to the magnetic properties of functional Fe₃O₄ nanometer particles, it has great applications in the fields of dyeing wastewater. It has been a kind of ideal adsorbent, which is apt to be separated and recycled. The purpose was to have emphatical research on the adsorption performance of dyes using functional magnetic nano microspheres as adsorbent in the study.Based on the purpose above mentioned, the main contents of this research mainly included the following aspects:1. The 15 nm Fe₃O₄ magnetic particles were successfully prepared by chemical co-precipitation method. FeCl₃·6H₂O and FeSO₄·7H₂O were used as raw materials and the NH3·H₂O was used as precipitating agent.Some influence factors such as material ration, crystallization temperature, pH, the choice of alkali source on the characteristic of the magnetic Fe₃O₄ particles were investigated and the properties of the product were characterized by TEM, XRD, VSM, TGA and FT-IR. The results showed that Fe₃O₄ magnetic particles with spinel structure had good thermal stability and high magnetic responsiveness, and its saturation magnetization value reached 62.78 emu·g^-1.2. Based on the existence of magnetic Fe₃O₄ particles, the author synthetized two kinds of magnetic Fe₃O₄ microspheres with functionalized modifications. Fe₃O₄ magnetic particles surface was modified by the -NH₂ group via silanization reagent （3-aminopropyl triethoxysilane）, then further amidation reaction was made to obtain sufficient -COOH group at the surface of particles. The characteristic of the Fe₃O₄ magnetic material were characterized by TEM, XRD, VSM, TGA and FT-IR. The results showed that the -NH₂ and -COOH groups were successfully modified to the surface of Fe₃O₄ magnetic particles. The modified magnetic particles remained its spinel structure, which saturation magnetization with slight decrease were 56.98 and 53.63 emu·g^-1 respectively. The modified magnetic particles still perform good solid-liquid separation, and it has no harmful effect for further dye adsorption.3. The adsorption of methylene blue （MB） and ethyl violet （EV） by amino functional magnetic microspheres were studied, and similar research were made to neutral red （NR） and methyl orange （MO） with carboxyl functional magnetic microspheres. Various influencing factors such as pH, initial concentration, adsorption time, ionic strength and temperature to adsorptive characteristic and the regeneration of magnetic microspheres and were studied.The experiments result showed as follows:1) The adsorption of MB by Amino functionalization magnetic microspheres was abviously affected by pH. Adsorption balance could be reached in 45 mins, and the experiment data was fitting the preudo-second-order equation. The adsorption was endothermic process with enthalpy change of 3.77 kJ/mol at 298-333K. The isotherm adsorption data accorded with the Langmuir model with a maximum adsorption amount of 70.42 mg/g and an adsorption equilibrium constant of 0.2160 L/mg. For the adsorption of EV by Amino functionalization magnetic microspheres, the adsorption amount which exhibits a maximum at the pH～9.5 increased with the increase of concentration. The process was endothermic process with enthalpy change of 3.54 kJ/mol at 298-328K and a maximum adsorption capacity of 29.06 mg/g. Following the increase of temperature, the adsorption of EV increased either.2) For the adsorption of NR by carboxyl functional magnetic microspheres,adsorption amount exhibit the most amount at the pH～4.5. The adsorption balance could be reached in 15 mins. At a certain concentration range, ionic strength barely had influence on the adsorption amount. The adsorption was endothermic process with the enthalpy change of 4.10 kJ/mol at 298-328K. The isotherm adsorption data accorded with the Langmuir model with a maximum adsorption amount of 32.48 mg/g and an adsorption equilibrium constant of 0.0247 L/mg. The adsorption to MO exhibits the most amount at optimal concentration of 80 mg/L. The process was a decalescence with the enthalpy change of 3.84 kJ/mol at 298-323K. The isotherm adsorption data accorded with the Langmuir model with a maximum adsorption amount of 56.82 mg/g and an adsorption equilibrium constant of 0.1107 L/mg.更多还原