| 题名 | 特征官能团修饰的硅基介孔材料制备及其对四环素类物质的吸附性能研究 |
| 作者 | 张紫阳 |
| 学位类别 | 博士 |
| 答辩日期 | 2015-05 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 刘会娟 ; 曲久辉 |
| 关键词 | 硅基介孔材料 SBA15 吸附 TC 机理 膜滤， Mesoporous silica materials, SBA15, Adsorption, Tetracycline， Mechnism, Membrane |
| 其他题名 | The preparation of mesoporous silica materials with functional groups and investigation of adsorption behaviors of tetracyclines antibiotics |
| 学位专业 | 环境工程 |
| 中文摘要 | 本论文主要针水中四环素类抗生素及其共存重金属，在分析其理化特征的基础上，根据 Fe可以与四环素发生络合的现象，运用金属掺杂和官能团嫁接方法研制相匹配具有特征官能团的硅基吸附材料，研究该吸附材料对水中四环素类抗生素及其共存重金属的吸附效能、过程与机理，初步探讨了吸附 -膜过滤组合工艺去除水中的四环素类抗生素的可行性。取得了以下成果： 合成一系列不同 Fe/Si比例的Fe（III）掺杂 SBA15吸附剂（Fe-SBA15），Fe（III）成功掺杂到 SBA15的骨架结构中，形成了一种含有大量介孔孔道的铁-硅介孔吸附剂。Fe/Si比从0升至 0.1时，骨架结构中的 Fe（III）会提供大量有效吸附位点，增加吸附剂对四环素（TC）的吸附，Fe/Si升高至0.2时，氧化铁颗粒的形成会抑制吸附剂对 TC的吸附。吸附剂对 TC的吸附速率较快，动力学符合准二级动力学模型，等温线符合Langmuir模型，最大吸附容量为155.76mmol/kg。吸附过程是一种单层化学络合反应。溶液 pH影响该吸附剂对TC的吸附，最佳的pH为5.0-7.0。吸附剂经五次再生后对 TC的吸附容量基本保持不变。吸附过程主要是通过吸附剂骨架中的 Fe（III）与 TC的酰胺基和酚羟基发生络合反应来实现。 针对水中四环素与重金属共存问题，通过一步嫁接法制备含有 Fe（III）和多氨基的双官能团介孔吸附剂（Fe-N,N-SBA15）。Fe（III）和氨基成功嫁接到分子筛的孔道中，未改变分子筛的三维结构。该吸附剂对四环素、土霉素（OTC）和金霉素（CTC）的吸附速率较快，吸附动力学符合准二级动力学模型。随着溶液 pH升高，吸附剂对三种四环素的吸附量都有先增高后降低的趋势，TC、OTC和 CTC的最佳 pH分别为5.2，4.4和5.6。吸附剂对 TC、OTC和CTC的最大吸附容量分别为 96.91、143.31和 69.15mmol/kg，吸附机理主要是通过吸附剂中Fe（III）与 TCs的氨基基团发生内层络合反应。吸附剂对TCs的吸附能力随着温度的升高而升高。TCs结构中 R1和 R2官能团以及不同的pKa是影响吸附剂对TC的吸附效果的主要因素。 进一步研究了 Fe-N,N-SBA15同时去除TC和Cu的效能。TC和Cu能促进对方在吸附剂上的吸附，吸附速率和吸附容量都有明显增加。溶液pH影响吸附剂同时去除 TC和 Cu的效能，TC、Cu以及 TC/Cu络合物的不同形态是决定性因素。离子种类和强度对吸附影响不大，吸附剂与吸附质之间形成了内层络合物。吸附剂对 TC的吸附是吸附剂中Fe（III）与 TC的氨基发生络合反应，对Cu的吸附主要是吸附剂中氨基基团与 Cu发生络合反应。由于TC-Cu络合物的作用，TC和Cu能利用桥连作用吸附到吸附剂不同的位点上，因此显著的促进对方在吸附剂上的吸附。 初步探讨运用吸附-膜过滤组合工艺去除水中 TC，吸附-膜过滤组合工艺可以用来去除水中 TC。吸附剂在膜表面形成滤饼层，但不会造成中空纤维膜污染。吸附剂再生后吸附效能与再生前相比会下降，TC的穿透时间和饱和时间会缩短。利用吸附剂吸附容量大，膜过滤工艺简单，可以同步去除水体中TC。 |
| 英文摘要 | In view of the tetracycline antibiotics (TC) and co-exist heavy metal in water, according to the complexation between TCs and iron/iron oxides, the mesoporous silica materials with functional groups were prepared by incorporation and modification methods. The mesoporous silica materials were then used to adsorb tetracycline antibiotics and heavy metal from water. The adsorption behavior, the adsorption process and adsorption mechanism were investigated.The adsorption-membrane method was used to elimination tetracycline from aqueous solution. The main conclusion were as followed: Fe-incorporated SBA15 (Fe-SBA15) with different contents of Fe(III) was synthesized. The results showed that Fe(III) was incorporated into the mesoporous silica framework of SBA15 and the adsorbents exhibited mesoporous structural order after co-condensation. As the Fe/Si ratio increased from 0 to 0.1, the Fe(III) incorporated into the mesoporous silica framework offered abundant active sites for the adsorption of TC. As the Fe/Si increased to 0.2, the new formed iron oxides decreased the adsorption capacity of TC onto the adsorbent. The adsorption of TC on Fe-SBA15 was fast and adsorption kinetics fitted the pseudo-second-order model perfectly. The Langmuir model fitted the adsorption better and the maximum adsorption capacity of TC onto Fe-SBA15 was 155.76 mmol/kg. The adsorption of TC on Fe-SBA15 was probably monolayer molecular adsorption. The solution pH effects the adsorption greatly, the optimized solution pH for the adsorption was around 5.0 to 7.0. The adsorption capacity was nearly unchanged after five regeneration cycle. The adsorption mechanism mainly involved inner-sphere surface complexes formed between tricarbonylamide, phenolic diketone groups of TC and the Fe(III) on the adsorbent. Focus on the co-exist of tetracycline and heavy metal in aquatic solution, a new sorbent made by grafting both multi-amino groups and Fe (III) on mesoporous silica SBA15 (named Fe-N, N-SBA15) was prepared. Amino group and Fe(III) were successfully incorporated onto SBA15, and the adsorbent preserved the mesoporous structural order after the functionalization. The adsorption of TC, oxytetracycline (OTC) and chlortetracycline (CTC) on Fe-N, N-SBA15 was fast and adsorption kinetics fitted the pseudo-second-order model perfectly. The adsorption capacity of TCs increased with the pH increased and decreased with pH increased further. The optimal pH was found to be 5.2, 4.4 and 5.6 for TC, OTC and CTC, respectively. The maximum sorption capacity to be 143.31, 96.91 and 69.15 mmol kg-1 for OTC, TC and CTC, respectively. The high adsorption capacity of antibiotics could be mainly attributed to the inner-sphere complexation of Fe (III) and TCs. The differences in the removal trends of the three TCs may be attributed to their different pKa values and the functioanl group in R1 and R2. The adsorbent was then used in the synchronous elimination of (TC) and Cu(II) from water. The adsorbent had high affinity for both TC and Cu(II) and synergistic effects on adsorption were found, as they coexist in water. The pH effect the adsorption greatly and can be associated with the pH-dependent speciation of TC, the complex formation of TC and Cu(II), and the surface properties of sorbents. The ionic strength had little effect on the adsorption of TC and Cu(II), the inner-sphere surface complexes were formed between the adsorbent and adsorbate. Fe(III) and amino groups on the adsorbent were complexed with the amide of TC and Cu(II),respectively. Increasing adsorption of TC and Cu(II) on the adsorbent could be attributed to the formation of complex TC-Cu(II) bridging. The adsorption-membrane process can be used to remove tetracycline antibiotic from water. The adsorbent formed a cake layer on the surface of membrane but did not cause the pollution of hollow fiber membrane. The adsorption capacity of sorbent decreased to some extent after regeneration and the time of breakthrough and saturation decreased a little. Due to the high adsorption capacity of mesoporous silica adsorbent and useful separation of membrane, tetracycline can be removed from aquatic solution by adsorption-membrane combined method. |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.rcees.ac.cn/handle/311016/34478]  |
| 专题 | 生态环境研究中心_环境水质学国家重点实验室 |
| 推荐引用方式 GB/T 7714 | 张紫阳. 特征官能团修饰的硅基介孔材料制备及其对四环素类物质的吸附性能研究[D]. 北京. 中国科学院研究生院. 2015. |
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