有色金属硫化矿选矿废水中含有黄药、乙硫氮、黑药等有毒有害物质的选矿药剂，若未经有效处理就排放，将对环境造成严重的污染。其中，黄药用量最大，污染特征最为典型，对人畜神经系统、肝脏器官和造血系统都会构成危害。因此，研究黄药的处理方法对矿业的环境保护具有重要的意义。传统的选矿废水处理方法，在处理黄药上具有不彻底等诸多缺点。非均相催化臭氧氧化技术具有对污染物氧化比较彻底，稳定性好等优点，有望成为一种很有应用价值的选矿废水处理技术。但，目前在选矿药剂降解机理、降解路径、催化剂表面结构和催化活性微观结构等领域，缺乏深入细致的研究，从而制约了该技术在选矿废水领域的应用和推广。 本论文以黄药为主要研究对象，采用浸渍法制备Pt、Au、Pd负载γ-Al₂O₃三种催化剂，考察了催化剂性能及非均相催化臭氧氧化降解黄药的影响因素，研究了分子结构、碳链长度对降解效果的影响，推测降解反应的有效成分，并以实际选矿废水进行处理效果验证，分析废水处理后回用的可行性。采用密度泛函理论，通过构建模型，研究了Pt、Au、Pd与γ-Al₂O₃表面Al原子和O原子的电子作用，Pt、Au、Pd负载γ-Al₂O₃在γ-Al₂O₃表面的微观构型，及其对γ-Al₂O₃表面与水分子和臭氧作用的影响，并建立黄药在Pt、Au、Pd负载γ-Al₂O₃催化剂表面的吸附模型，在原子水平上提出了黄药的催化降解原理。主要研究内容和结论如下： (1)浸渍法制备出的Pt、Au、Pd负载γ-Al₂O₃三种催化剂，都具有较高的催化活性，对丁基黄药配制的模拟废水具有良好的降解效果。经SEM、XRD和XPS等表征，证实了Pt、Au、Pd负载结果。催化剂制备过程煅烧温度、贵金属负载浓度和煅烧时间均对催化剂性能有影响。 (2)以丁基黄药为降解对象，Pt、Au、Pd负载γ-Al₂O₃三种催化剂中，负载Pt降解效果最好，负载Pd效果最差。相同条件下，黄药碳链长度越长，降解程度越低，相同碳原子数目的黄药，正构体较异构体降解更为彻底。丁基黄药最终降解产物可能为硫酸盐、碳酸盐和二氧化碳。Pt、Au、Pd负载γ-Al₂O₃催化剂对乙硫氮和黑药也有明显的降解效果，对实际选矿废水中COD具有较好的降解效果，相对于单独臭氧氧化非均相臭氧催化法能够提高COD去除率。降解反应中，推测出自由基为有效作用成分。 (3)基于密度泛函构建模型研究发现，Pt、Au、Pd与γ-Al₂O₃接触后发生了很强的电子相互作用，表面的Al获得电子，而负载的金属和O原子失去电子。因负载金属接触的作用，界面上Al和O原子的亲电亲核性发生了改变，亲电性在Pt负载的表面上最强，而亲核性最弱，在Au和Pd负载的表面上的亲电亲核性相近。理论分析认为Pt负载的γ-Al₂O₃表面对有机物的氧化性质最好。负载金属的d轨道与O的2p轨道参与了反应，而Pt的5d轨道与O的2p轨道作用是最强的，此外，Al的3p轨道也发生了明显变化。 (4)Pt、Au、Pd在γ-Al₂O₃表面负载微观构型DFT研究发现，Pt、Au、Pd原子在γ-Al₂O₃表面形成原子簇的结构，其中3个金原子在γ-Al₂O₃表面形成三角形的簇结构最稳定，而Pt和Pd则是4个原子形成四面体的原子簇结构为最稳定结构。Pt、Au、Pd原子主要与γ-Al₂O₃表面的铝原子作用，其次是氧原子。 (5)负载贵金属的γ-Al₂O₃表面与水分子、臭氧的作用都比没有负载氧化铝的表面要强，吸附能都更负，Pt、Au、Pd参与了催化过程中自由基的形成，负载贵金属的γ-Al₂O₃表面更容易解离水分子形成羟基自由基，臭氧在γ-Al₂O₃表面容易解离形成氧自由基，从而促进催化降解。理论研究发现，负载Pt的γ-Al₂O₃催化剂性能最好，其次是金，钯最差。 (6)黄药在负载铂的γ-Al₂O₃表面吸附作用最强，其次是金，最弱是钯。黄药分子中硫原子与γ-Al₂O₃表面的铂原子具有较强的成键作用，金和钯原子与硫原子的反键作用较强，成键作用较弱。黄药分子的降解最有可能是从硫碳键开始断裂，最后是烃基的氧化分解。 关键词：Pt、Au、Pd负载γ-Al₂O₃催化剂，非均相臭氧催化降解，第一性原理，黄药 中图分类号：X131.2

 The ore dressing agent containing toxic and harmful substances such as xanthate, ethyl sulfide and black medicine in the non-ferrous metal ore dressing wastewater will be discharged if not treated effectively, which will cause serious pollution to the environment. Among them, the yellow medicinal amount is the largest, the pollution characteristics are the most typical, and it will pose a hazard to the human and animal nervous system, liver organs and hematopoietic system. Therefore, research on the treatment of xanthate is of great significance to the environmental protection of mining industry. The traditional method of mineral processing wastewater treatment has many disadvantages such as incomplete treatment of xanthate. Heterogeneous catalytic ozonation technology has the advantages of relatively complete oxidation of pollutants and good stability, and is expected to become a valuable beneficiation ore dressing wastewater treatment technology. However, at present, in the fields of degradation mechanism, degradation path, catalyst surface structure and catalytic activity microstructure, there is a lack of in-depth and meticulous research, which restricts the application and promotion of this technology in the field of ore dressing wastewater. In this thesis, xanthate was used as the main research object.Three catalysts of Pt, Au and Pd loaded γ-Al₂O₃ were prepared by impregnation method. The catalyst properties and the factors affecting the heterogeneous catalytic ozonation degradation of xanthate were investigated. The effects of molecular structure and carbon chain length on the degradation were studied. The effective components of the degradation reaction are presumed, and the actual ore dressing wastewater is used for verification, and the feasibility of recycling the wastewater after treatment is analyzed. Density functional theory was used to study the electronic interactions of Pt, Au, Pd and Al, O atoms on the surface of γ-Al₂O₃. The microstructure of Pt, Au and Pd on the surface of γ-Al₂O₃, and the effects of Pt, Au and Pd on the surface of γ-Al₂O₃ and the action of water molecules and ozone were studied. The adsorption model of xanthate on the surface of Pt, Au and Pd supported γ-Al₂O₃ catalyst was established. The principle of catalytic degradation of xanthate was proposed at the atomic level. Main research contents and conclusions: (1)The three catalysts of Pt, Au and Pd loaded with γ-Al₂O₃ prepared by impregnation method have high activity and have good degradation effect on simulated wastewater prepared by butyl xanthate. The results of Pt, Au and Pd loading were confirmed by SEM, XRD and XPS. The calcination temperature, the precious metal loading concentration and the calcination time during the preparation of the catalyst all have an effect on the performance of the catalyst. (2)With butyl xanthate as the degradation target, Pt, Au, Pd loaded γ-Al₂O₃ catalysts, the Pt degradation effect was the best, and the load Pd effect was the worst. Under the same conditions, the longer the carbon chain length of xanthate, the lower the degree of degradation, and the same number of carbon atoms, the normal body is more thoroughly degraded than the isomer. The final degradation products of butyl xanthate may be sulfates, carbonates and carbon dioxide. Pt, Au and Pd supported γ-Al₂O₃ catalysts also have obvious degradation effects on ethylsulfide nitrogen and black medicine, and have good degradation effect on COD in actual beneficiation wastewater. Heterogeneous ozone catalysis can increase COD removal rate compared to ozone oxidation alone. In the degradation reaction, it is presumed that the radical is an effective component. (3)Based on the density functional model, it is found that a strong electronic interaction occurs after Pt, Au and Pd are in contact with γ-Al₂O₃. Al on the surface acquires electrons, while the supported metal and O atoms lose electrons. Due to the action of metal contact, the electrophilic nucleophilicity of Al and O atoms at the interface changed, the electrophilicity was the strongest on the surface of the Pt load, and the nucleophilicity was the weakest, on the surface of the Au and Pd loading. Electrophilic nucleophilicity is similar. The Pt-loaded γ-Al₂O₃ surface is the best for the oxidizing properties of organic matter. The d-orbital of the metal participates in the reaction with the 2p orbital of O, while the 5d orbital of Pt and the 2p orbital of O are the strongest. In addition, the 3p orbital of Al also changes significantly. (4)Pt, Au, Pd on the surface of the γ-Al₂O₃ supported microscopic configuration DFT study, platinum, gold and palladium atoms form a cluster structure on the surface of γ-Al₂O₃, in which three gold atoms form a triangle on the surface of γ-Al₂O₃ The cluster structure is the most stable, while platinum and palladium form the tetrahedron as the most stable structure. The platinum, gold, and palladium atoms mainly interact with the aluminum atom on the surface of γ-Al₂O₃ , followed by the oxygen atom. (5)The surface of γ-Al₂O₃ loaded with noble metal has stronger interaction with water molecules and ozone than the surface without alumina, and the adsorption energy is more negative. Platinum, gold and palladium participate in the formation of free radicals in the catalytic process, and the noble metal is supported. The surface of γ-Al₂O₃ is more likely to dissociate water molecules to form hydroxyl radicals, and ozone is easily dissociated on the surface of γ-Al₂O₃ to form oxygen radicals, thereby promoting catalytic degradation. It was found that platinum-loaded γ-Al₂O₃ has the best catalytic performance, followed by gold and palladium. (6)Xanthate has the strongest adsorption on the surface of platinum-loaded γ-Al₂O₃, followed by gold, and the weakest is palladium. The sulfur atom in the xanthate molecule has a strong bonding effect with the platinum atom on the surface of γ-Al₂O₃, and the anti-bonding action between the gold and palladium atoms and the sulfur atom is strong, and the bonding effect is weak. The first step of degradation of the xanthate molecule is most likely the initiation of cleavage of the sulphur-carbon bond, and finally the oxidative decomposition of the hydrocarbyl group. Key words: Pt, Au, Pd supported γ-Al₂O₃ catalyst, heterogeneous ozone catalytic degradation, first principles, xanthate Chinese Library Classification Number: X131.2