建筑垃圾合成沸石基吸附材料研究
文献类型：学位论文
| 作者 | 李寅明 |
| 学位类别 | 博士 |
| 答辩日期 | 2014-05 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 张付申 |
| 关键词 | 建筑垃圾 沸石化陶粒 钙霞石 CTAB改性 水热合成 Construction and demolition waste Zeolitizated ceramsite Calcium-bearing cancrinite CTAT-modification Hydrothermal synthesis |
| 其他题名 | Development of zeolite-based sorption materials from construction and demolition waste |
| 学位专业 | 环境工程 |
| 中文摘要 | 近年来，由于快速的城市扩张与大规模的旧城改造，建筑行业得到了突飞猛进的发展，由此产生了大量的建筑垃圾。建筑垃圾是在新建筑物施工和既有结构拆除过程中产生的废弃物，其化学成分与粘土相近，具有制备陶粒的潜力；另外，建筑垃圾中的金属、塑料、纤维织物等组分回收之后，剩余物主要是由SiO2-Al2O3-CaO-Fe2O3组成，适合合成沸石类功能材料。鉴于此，本研究主要开展了建筑垃圾合成沸石化陶粒、六棱柱钙霞石和全氟化合物吸附材料的研究，以期为建筑垃圾的高附加值产业化利用提供科学指导： 本研究的主要研究结果如下： （1）根据建筑垃圾与湿污泥组成与形态特征上的互补性，利用建筑垃圾配合湿污泥烧制多孔轻质陶粒。研究发现，湿污泥的最佳添加量为45%，烧结温度 970℃，最佳升温速率范围为12-18℃/min，最佳保温时间范围为10-15min。生产的陶粒产品具有低密度（密度＜1g/cm3）、低吸水率（吸水率4.2%）、高筒压强度（1.51MPa）等优点，符合GB/T 17431-2010中规定500级人工轻集料的强度和吸水率标准。陶粒可以通过碱水热反应进一步转化为沸石化陶粒。沸石化反应的最佳合成条件为：NaOH浓度4mol/L，反应温度160℃，反应时间12h，产物为以八面沸石为单一晶相的沸石化陶粒。陶粒沸石化之后，八面沸石晶体在沸石化陶粒表面多以柱状晶体堆积而成的球形凸起为主，在内部孔壁柱状晶体多以簇状分布。沸石化陶粒比表面积约50 m2/g,较沸石化处理前的污泥-建筑垃圾陶粒提高了近20倍。浸出实验结果显示，沸石化陶粒实现了有害重金属的有效固定，满足危险废物鉴别标准（GB5085.3-2007）的要求。吸附实验结果表明，沸石化陶粒对Ni2+的吸附等温曲线与Langmuir吸附模型拟合较好，说明吸附过程属于单分子层吸附，化学吸附占支配地位。不同粒径的沸石化陶粒对Ni2+均具有较高的吸附能力，吸附容量随粒径减小而增加。 （2）以建筑垃圾为原料直接通过碱水热反应合成一种自然界稀少的似长石类沸石矿物-钙霞石，傅里叶变换红外光谱（FTIR）、扫描电子显微镜（SEM）等的分析结果显示，合成的钙霞石是一种稀有的类型，其特点是具有以六棱锥为末端的六棱柱结构，六棱柱晶体的宽度介于100nm到1000nm之间，是一种纳米尺寸的矿物。 （3）通过碱融-水热反应和十六烷基三甲基溴化铵（CTAB）改性技术成功制备出以建筑垃圾为主要原料的有机改性吸附剂（CMCDSS），对全氟辛烷磺酰基化合物类污染物（PFOS，文中以全氟辛基磺酸钾为例）具有良好的吸附净化效果。吸附实验结果显示，PFOS在CMCDSS上能实现高效快速吸附，2.5h就能达到吸附平衡。吸附于CMCDSSs上的PFOS量随着CTAB负载量的增加而逐渐增加。溶液pH和初始浓度对PFOS在CMCDSS上的吸附行为具有显著影响，CMCDSS在酸性溶液中（pH= 2-6）具有良好的应用效果。在不同的溶液体系中，影响PFOS吸附的主要因素不同，静电吸附、疏水分配作用、氢键作用和配位体交换作用均参与PFOS在CMCDSS上的吸附行为。 |
| 英文摘要 | Recent years have witnessed a significant amount of construction and demolition waste (C&D waste) as a result of rapid urbanization and large scale of construction activities in China. C&D waste is produced by the construction of new buildings and the demolition of existing structures. After the recovery of metals and organic materials, such as plastics, fabrics, the residual of the C&D waste, mainly made of SiO2-Al2O3-CaO-Fe2O3, presenting a similar composition of natural zeolite, have the potential and can be employed as raw material to synthesize zeolite-like material. C&D wastes, possessing the similar chemical composition with the clay, have the potential to be used as the raw material for fabrication of ceramisite. My research covered three sections, (1) Porous sorption composite of zeolite-ceramsite derive from sludge-construction and demolition waste. (2) Calcium-bearing cancrinite with hexagonal prismatic structure derived from construction and demolition waste (3) Cetyltrimethyl Ammonium Bromide -modified sorbent derived from C&D waste for removal of perfluorooctane sulfonate (PFOS) from water. The significant results in scientific and practical value were as follows. （1）Wet sewage sludge and C&D waste were utilized as major raw materials for the fabrication of porous ceramsite based on the complementarity of their composition and morphological characteristics. The optimized appropriate dosage of wet sewage sludge, sintering temperature, heating rate range, and holding time range for ceramsite fabrication were 45%(by weight), 970℃, 12-18℃/min and 10-15min respectively. Sludge-C&D waste ceramsite has lower density(＜1g/cm3), lower water sorption(4.2%) and higher intensity (1.51MPa).Sludge-C&D waste ceramsite can be converted into functional sorption composite after zeolitization by hydrothermal synthesis process. The optimized NaOH concentration, reaction temperature and reaction time for the ceramsite zeolitization were 4 mol/L, 160℃ and 12h respectively. The obtained hydrothermal product was zeolite-ceramsite composite consisted of single faujasite phase.Spherulite formed from the accumulation of prismatic faujasite crystal deposited on the surface of zeolite-ceramsite composite, cluster crystal of faujasite accumulated onto hole wall inside the zeolite-ceramsite composite. The specific surface area of the zeolite-ceramsite composite approached 50 m2/g, about 20 times more than that of the sludge-C&D waste ceramsite．Leaching results indicated that heavy metals in the composite were effectively immobilized and met the identification standards for hazardous wastes-identification for extraction toxicity (GB5085.3-2007). Adsorption experiments of Ni2+ on the zeolite-ceramsitecomposite elucidated that the results could be well fitted by Langmuir isotherm, indicating a monolayer adsorption was performed and chemical adsorption was the predominant process. The adsorption amounts of Ni2+ on the zeolite-ceramsite composite enhanced along with the decrease of composite particle size. (2) One of the rarer members of the feldspathoid group of minerals, cancrinite, was successfully and directly synthesized from construction and demolition waste (C&D waste), realizing the high value-added utilization of this raw base material. Alkaline hydrothermal reaction was the main process for the synthesis of cancrinite. The synthesized cancrinite was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). The crystal structure of products obtained at different reaction time were identified by X-ray diffraction (XRD) to confirm the transformation mechanisms of cancrinite synthesis from C&D waste. Analysis results demonstrated that synthesized calcium-bearing cancrinite was hexagonal prismatic crystal, terminated by a low hexagonal-pyramid. The width of hexagonal prismatic crystal of cancrinite was between 100 nm and 1000 nm. （3）Construction and demolition waste ( C&D waste ), was employed as a raw base material for the cost-effective and practicable sorbent synthesis, which can be developed for application in abrupt PFOS pollution accidents.The waste material underwent alkaline fusion-hydrothermal synthesis and Cationic surfactant Cetyltrimethyl Ammonium Bromide ( CTAB ) modification process to form CTAB-modified sorbent ( CMCDSS ). Experimental results showed that PFOS could be effectively and rapidly adsorbed on CMCDSS, and sorption equilibrium was achieved within 2.5 h. The sorption amounts of PFOS on CMCDSS enhanced along with the increase of CTAB loading amount. Moreover, the CTAB-modified sorbent can be applied effectively under acidic condition at pH 2-6 and various removal mechanisms were clarified at different sorption conditions.In the PFOS sorption process under different solution systems, the dominant factors affecting PFOS sorption were different, electrostatic attraction, hydrophobic partition, hydrophobic interaction, hydrogen-bond interaction and ligand exchange reaction were involved in the |
| 公开日期 | 2015-07-07 |
| 源URL | [http://ir.rcees.ac.cn/handle/311016/15699]  |
| 专题 | 生态环境研究中心_固体废弃物处理与资源化实验室 |
| 推荐引用方式 GB/T 7714 | 李寅明. 建筑垃圾合成沸石基吸附材料研究[D]. 北京. 中国科学院研究生院. 2014. |
入库方式： OAI收割
来源：生态环境研究中心
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