【作者】 张严严；

【导师】 罗永明；

【作者基本信息】 昆明理工大学 ， 环境科学， 2012， 硕士

【摘要】 随着水污染问题的日益严重和出水水质要求的进一步提高,常规的水处理技术对受污染水体中污染物的去除能力明显不足。因此,开发高效、经济、简便的除重金属污染技术尤为必要。吸附法是去除水中污染物的有效方法之一,但常规的吸附材料大多存在吸附容量低和选择性差等缺点。因此,针对水中重金属污染物的吸附去除这一热点问题,本文研究并开发了有机无机复合介孔材料,将其应用于重金属废水处理过程中,作为一种高效吸附剂,考察其对水中Cr(Ⅵ)的吸附去除效果及机理,为水质安全提供有效的技术保障,同时对Cr(Ⅵ)污染状况提供有效的解决方法和途径。本文从有机无机复合介孔材料着手,根据水中Cr(Ⅵ)的特性,从以下几个方面考察其在Cr(VI)废水处理领域中的应用前景及其作用机制：(1)吸附剂的对比筛选研究首先用不同的有机组份(十二烷基三甲基溴化铵-DTAB;十四烷基三甲基溴化铵-TTAB;十六烷基三甲基溴化铵-CTAB;十八烷基三甲基溴化铵-STAB)在不同的干燥温度(110℃；150℃；190℃；230℃)下,水热合成法合成有机无机复合介孔材料。分别记为HMx-y(x=D、T、C、S；y=110、150、190、230)。将所有复合材料吸附水中Cr(Ⅵ)的效果进行对比研究。结果表明：在铬的初始浓度为50mg/l、100mg/l或150mg/l、pH=2.0、室温25±1℃、0.1g/L吸附剂的实验条件下,以十六烷基三甲基溴化铵为有机组分,在110℃下干燥2天合成的复合材料(HMC-110)对Cr(Ⅵ)的吸附效果最好。(2)批次实验法研究HMC-110对Cr(Ⅵ)的吸附效果静态条件下研究吸附剂HMC-110对铬的吸附。同时考察溶液的pH值、吸附时间、铬的初始浓度、吸附温度、共存离子和吸附剂用量等因素对吸附过程的影响。结果表明：溶液的pH值、吸附时间、初始浓度、吸附温度、共存离子和吸附剂用量等因素对吸附过程均有不同程度的影响。吸附剂HMC-110在pH2对Cr(Ⅵ)表现出较强的吸附能力,最高吸附率出现在pH=2附近,值为99.7%；随着Cr(Ⅵ)初始浓度的增高,吸附量呈上升趋势,最高可达211mg/g的吸附量；去除率呈下降趋势。吸附剂用量是影响去除率的又一重要因素,随着吸附剂用量的增加,铬的去除率快速上升；在NO3-,Cl-,C032-,PO43-,SiO42-,SO42-等共存离子存在的情况下,除SiO42-离子外其他竞争吸附基本不影响HMC-110对铬的吸附。Cr(VI)在HMC-110上的吸附符合二级动力学模型,吸附等温线符合Langmuir模型,最大吸附量随着温度的升高而降低,吸附为放热过程；复合材料吸附铬的机理为重铬酸根与HMC-110表面的Si-O-Si形成电子供体/受体配位作用。脱附实验表明Cr(VI)在HMC-110上结合力较强,材料的再生效果不理想。(3)利用响应曲面法优化HMC-110吸附Cr(VI)的实验条件。利用响应曲面法研究HMC-110对Cr(Ⅵ)的吸附条件,考察了溶液的pH；投加量；反应温度等对吸附的影响,Box-Behnken实验模型设计,响应曲面分类研究法分析数据,软件为Design Expert Version8.0(Stat Ease, USA)。最后,用粉末X射线衍射(XRD)、扫描电镜(SEM)、低温N2吸附-解吸附技术、透射电镜(TEM)、差示热扫描热量法(DSC),热重-差热分析(TG-DTA)对材料进行了表征。结果表明,有机、无机组分成功的复合在一起,材料具有明显的介孔孔道结构。更多还原

【Abstract】 With the increasingly serious water pollution problems and further improvement of the effluent quality required, conventional water treatment technology for the removal of contaminants in polluted water is obviously inadequate. Therefore, it is particularly necessary to develop efficient, economic, and sample technology to get rid of micro-pollution. Adsorption is one of the effective methods to remove pollutants from water, but most of the conventional adsorption materials have low adsorption capacity and poor selectivity, so, in view of the hot issue of adsorption and removal of pollutants in the water, this paper studied and developed some organic and inorganic compound mesoporous materials, which will apply to the treatment process of heavy metal wastewater, as an efficient adsorbent, we investigated its adsorption and removal efficient and mechanism on the Cr (Ⅵ) in water, and will provide effective technology support for the security of water quality, the efficient solutions and means for Cr (Ⅵ) pollution situations at the same time.This paper based on the organic-inorganic hybrid mesoporous materials, according to the Cr (Ⅵ) characteristics in water, investigated the application prospect and mechanism of the materials in the field of Cr (Ⅵ) waste water treatment from the following aspects:(1) comparison and screening experiment study of adsorbentFirst synthesised the organic-inorganic compound mesoporous materials by hydrothermal synthesis with different organic components (Dodecyltrimethylammonium Bromide; Myristyltrimethylammonium bromide; Hexadecyl trimethyl ammonium Bromide; Trimethylstearylammonium Bromide), in different drying temperature (110℃;150℃;190℃;230℃). separately recorded as HMx-y(x=D,T,C,S:=110,150,190,230)We made a comparative study about the effect that all compound materials adsorption Cr (Ⅵ) that in water.Results indicated that under the experimental conditions of the initial concentrations of chromium in50mg/l or100mg/1, pH=2.0, room temperature of25±1℃,0.1g/L adsorbent,16-alkyl trimethyl ammonium bromide as organic compound, dry2days at110℃, composite material (HMC-110) synthesised worked best for Cr (Ⅵ) adsorption.(2) batch experim(?)al study on the adsorption effect of HMC-110for Cr (VI) We studied the adsorbent HMC-110on chrome adsorption under static conditions. Investigated the factors include the pH value of solution, adsorption time, initial concentration of chromium, adsorption temperature, coexistence ions and absorbent dosage, which influenced the adsorption process.The results showed that the factors include the pH value of solution, adsorption time, initial concentration, adsorption temperature, coexistence ions and absorbent dosage, which had an influence of different level on adsorption process. Adsorbent HMC-110represented strong adsorption ability to Cr (Ⅵ) in pH=2, the highest adsorption rate appeared in the pH=2near, value is99.5%;With the initial concentration of Cr (Ⅵ) increased, the removal rate of HMC-110for Cr (Ⅵ) declined, when initial concentration of Cr (Ⅵ) was1000mg/1, adsorption rate was very low.Adsorbent dosage was another important factor affected the adsorption rate, with increase of the content of absorbent, chromium adsorption rate rised fast; under the condition that coexistence ion include NO3-, Cl-, CO32-, PO43-, SiO42-, SO42-existed except SiO42-ions, other competitive adsorptions were barely influence the adsorption of HMC-110for chrome, we infer the mechanism of HMC-110adsorb chrome was Cr2O72-and Si-O-Si that on the surface of HMC-110formed electron donor/receptor coordination effect.The adsorption of Cr (VI) for HMC-110in line with the second-level dynamics model, meet the Langmuir adsorption isotherm models, the maximum adsorption capacity lowering with the raising of temperature, adsorption was exothermic processes; the pH values of solution influenced the adsorption of HMC-110for Cr (Ⅵ); desorption experiments suggested that adhesion of Cr (VI) in HMC-110was strong.(3) Optimize the experimental conditions of adsorption of HMC-110for Cr (VI) by using response surface methodWe used the response surface method to study the adsorption conditions of HMC-110for Cr (Ⅵ), investigated ihe pH value of the solution; dosage; reaction temperature and so (?) that influenced the adsorption, Box-Behnken experimental model design, response surface classification research method analysis data and software was the Design Expert Version8.0(Stat Ease, USA). Finally, material characterization was provided by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), N2adsorption-desorption technology at low temperature, transmission electron microscopy (TEM), differential thermal scanning thermal methods (DSC) and TG-DTA (TG-DTA). The results showed that organic and inorganic components compound together successfully, materials had obvious mesoporous pore structure.更多还原