改性凹凸棒粘土的制备及其光催化降解盐酸四环素废水的研究

发布时间：2017-12-31 14:30

本文关键词：改性凹凸棒粘土的制备及其光催化降解盐酸四环素废水的研究　出处：《长安大学》2015年硕士论文　论文类型：学位论文

【摘要】：抗生素废水属于难处理的工业废水,如果大量进入水环境系统,将会严重影响人体健康和生态环境。凹凸棒粘土是一种强吸附性、易获得的矿物粘土,在吸附处理抗生素废水方面具有显著优势。而TiO2、ZnO等光催化剂在处理抗生素废水方面也取得了一定的成效,展现了半导体光催化技术在处理抗生素废水的巨大潜能。本文旨在通过对凹凸棒粘土的改性,制备出更具降解效率的新型光催化材料,所制备的材料有Ti-ATPs、Zn/Ti-ATPs、Ni/Ti-ATPs等,其中以Zn/Ti-ATPs光催化剂性能最优。制备的新材料既能发挥凹凸棒粘土的强吸附性,又能结合复合光催化剂提高光能的利用效率,使降解盐酸四环素的能力大大提高。此外,材料的制备过程均采取浸渍-煅烧法,操作简便易于实现,为抗生素废水的处理研究提供新的思路。本文采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、紫外-可见漫反射吸收光谱(UV-vis)等方法对改性凹凸棒粘土的结构、形貌和组成进行表征,并以盐酸四环素为目标污染物,考察改性材料在可见光下的降解效果。(1)制备Ti-ATPs,改性后的凹凸棒粘土协同吸附与光催化过程,具备了良好的降解能力。UV-vis结果表明经过Ti改性后的ATPs光催化剂光谱图在紫外光波段吸光度有一定的提高,在可见光波段虽有提高但不太明显。以盐酸四环素为目标污染物进行光催化降解实验,研究表明:在Ti含量占ATPs的40%,450℃煅烧温度下得到的复合材料光催化降解盐酸四环素效果最好,在300W氙灯光源(250nm~800nm)下反应120min对盐酸四环素的降解率达75.8%。(2)用Zn和Ti同时对凹凸棒粘土进行改性,制备Zn/Ti-ATPs。改性后的凹凸棒粘土协同吸附与两种半导体复合光催化过程,相比之前具备了更优的降解能力。UV-Vis光谱结果表明Zn/Ti-ATPs光催化剂的光谱图出现了明显红移现象,在近紫外光区和可见光区内吸光度均有明显的提升。以盐酸四环素为目标污染物进行光催化降解实验,实验结构表明:在Zn/Ti金属摩尔配比为3:1,400℃煅烧温度下得到的复合材料光催化性能最好;在盐酸四环素溶液pH为7,溶液初始浓度为20mg/L以及催化剂的投加量为0.4g/L时,在可见光照射120min后,新材料Zn/Ti-ATPs对盐酸四环素的降解率达到最高,为94.64%。Zn/Ti-ATPs复合材料相比于Ti-ATPs和Zn-ATPs均有较高的降解性能。另外,材料稳定性较好,重复三次使用时降解率还可以达到77.42%。(3)用同种方法制备的Ni/Ti-ATPs复合材料不具备光催化活性。以盐酸四环素为目标污染物进行光催化降解实验,发现在不同煅烧温度和金属比例条件下制备的Ni/Ti-ATPs均不具备光催化能力。这是由于没有最合适的温度能使TiO2和NiO同时处于光催化性能最好的晶型状态,在其余温度下两种氧化物互相占据光催化位点,影响光催化反应的进行,使得Ni/Ti-ATPs不具光催化活性,降解效率也仅仅停留在改性前粘土的吸附水平。本文对凹凸棒粘土进行系列改性实验后,制备的Zn/Ti-ATPs对盐酸四环素废水有很高的降解效率。材料光催化活性高、性能稳定、回收方便,对水处理领域的研究具有显著的理论意义。
[Abstract]:Antibiotic wastewater is one of industrial wastewater treatment, if poured into the water system, it will seriously affect human health and ecological environment. The attapulgite clay is a kind of strong adsorption, easy to obtain the clay minerals, has a significant advantage in the treatment of antibiotic wastewater by adsorption. TiO2, ZnO photocatalyst has achieved certain results in the treatment of antibiotic wastewater, show the semiconductor photocatalytic technology has huge potential in the treatment of antibiotic wastewater. This paper is based on the modified attapulgite clay, producing new photocatalytic materials more degradation efficiency, the prepared materials are Ti-ATPs, Zn/Ti-ATPs, Ni/Ti-ATPs, and Zn/Ti-ATPs the photocatalytic performance optimal. The preparation of new materials can play a strong adsorption of attapulgite clay, and can improve the utilization efficiency of solar energy combined with the composite photocatalyst, the degradation ability of tetracycline hydrochloride Greatly improved. In addition, impregnation calcination method adopt material preparation process is simple, easy to implement, and provide a new way for the treatment of antibiotic wastewater. In this paper, using scanning electron microscopy (SEM), X ray diffraction (XRD), optical absorption spectrum UV - visible diffuse reflectance (UV-vis) structure. The method of modified attapulgite clay, morphology and composition were characterized, and the tetracycline hydrochloride as the target pollutants, study on degrading effect of modified materials under visible light. (1) preparation of Ti-ATPs modified attapulgite clay synergistic adsorption and photocatalytic process, have good degradation ability of.UV-vis results after that Ti modified ATPs photocatalyst spectra after a certain improvement in the ultraviolet absorbance in the visible light wave is improved but not obviously. The photocatalytic degradation of tetracycline hydrochloride as the target pollutant experiment, the research shows that: in T The content of I accounted for 40% of ATPs, the best effect of the Composite Photocatalytic Degradation of tetracycline hydrochloride was 450 DEG C calcination temperature, the 300W xenon light source (250nm~800nm) reaction for 120min degradation of tetracycline hydrochloride was 75.8%. (2) with Zn and Ti at the same time the attapulgite clay modification, preparation of modified Zn/Ti-ATPs. the CO adsorption of attapulgite clay and two kinds of semiconductor photocatalytic process, compared with before the degradation ability of.UV-Vis spectra showed better spectra of Zn/Ti-ATPs photocatalyst showed a red shift phenomenon in ascension has obvious absorbance near ultraviolet region and visible region. Tetracycline as target pollutants by photocatalysis the degradation experiment, experimental results show that: the photocatalytic activity of the composite is 3:1400 calcined temperature in Zn/Ti molar ratio of the metal in the best; tetracycline hydrochloride solution pH 7 Solution The liquid concentration was 20mg/L and the catalyst dosage is 0.4g/L, in 120min visible light irradiation, the new material Zn/Ti-ATPs on the degradation of tetracycline hydrochloride was highest for 94.64%.Zn/Ti-ATPs composites compared to Ti-ATPs and Zn-ATPs had a higher degradation performance. In addition, the material has good stability and repeated three times using the degradation rate can also be 77.42%. (3) Ni/Ti-ATPs composite materials with the same preparation method has no photocatalytic activity. With tetracycline hydrochloride as target pollutants photocatalytic degradation experiments, found at different calcination temperature and metal ratio under the condition of preparation of Ni/Ti-ATPs not have the photocatalytic ability. This is due to the lack of the most suitable temperature can make TiO2 and NiO in the crystalline state the best photocatalytic performance at the same time, in the temperature of two oxide photocatalytic sites occupy each other, influence of photocatalytic reaction That makes the Ni/Ti-ATPs has no photocatalytic activity. The degradation efficiency also only stay in the level of the adsorption behavior of clay. This series of experiments on the modified attapulgite clay, preparation of Zn/Ti-ATPs with high degradation efficiency of tetracycline hydrochloride wastewater. The material has high photocatalytic activity, stable performance, convenient recovery, has the theory significance to the research in the field of water treatment.

【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703

【参考文献】