牙科修复用CuO掺杂纳米二氧化钛的制备与表征

目的 通过氧化铜掺杂,制备改性氧化铜纳米二氧化钛光催化剂,检测氧化铜掺杂对CuO/TiO₂复合光催化剂吸收光谱的影响,为研制口腔临床修复功能性材料提供依据。方法 采用共沉淀法制备CuO/TiO₂（CuO掺杂纳米二氧化钛）,通过X射线衍射仪（XRD）、扫描电镜（SEM）和紫外-可见光吸收光谱（UV-vis谱）对其形态、结构、组成和性质进行表征。结果 成功制备了CuO/TiO₂复合光催化剂,不同CuO掺杂比的TiO₂的形貌基本不变,CuO掺杂使CuO/TiO₂吸收光谱发生红移,增加了可见光的吸收边界,提高可见光响应。结论 掺杂CuO后的光催化剂有效地提高其可见光响应能力,减少了空穴和电子复合,提高了可见光响应的性能。本研究对解决口腔临床修复对抗菌抑菌自洁特性材料的需求具有参考意义。     

Photocatalysts synthesized via plant mediated extracts for degradation of organic compounds: A review of formation mechanisms and application in wastewater treatment

Photocatalysis is a promising technology to remove several persistent and recalcitrant pollutants in water and wastewater. Most of the conventional chemical and physical synthesis routes of photocatalysts result in the release of toxic pollutants to the environment and hence green synthesis is a better alternative. Green synthesis of photocatalyst using plants, fungi, bacteria, yeast, and other biological sources is widely explored in recent years. The presence of various biomolecules used in green synthesis replaces conventional reducing and stabilizing agents such as hydrazine, sodium borohydride, ascorbic acids, and other polymer substitutes. This review focuses on the synthesis of photocatalysts using plant extracts through different synthesis routes and explores the efficacy of photocatalyst synthesized via plant extract mediated synthesis routes in the photodegradation of organic compounds present in water. The pathway as well as the factors affecting the formation of photocatalysts, the role of plant extract in the photocatalytic properties are explored in detail. The action of plant-mediated photocatalyst on the pollutant and the underlying predominant degradation mechanism are also discussed. Besides, this study gives an insight into the recyclability of the photocatalyst synthesized via plant extract mediated synthesis routes and addresses future perspectives and the challenges of green photocatalysts.     

碳纳米管负载TiO2光催化降解腈纶废水

目的：采用溶胶-凝胶法制备负载二氧化钛的多壁碳纳米管，对其结构进行X-射线粉末衍射（XRD）、透射电镜表征，探讨负载二氧化钛的碳纳米管用于腈纶废水的处理。方法：以300W中压汞灯为光源，在250ml的腈纶废水中加入100mg负载有TiO2的碳管光催化处理1h，废水的CODCr去除率达22％；经Fenton试剂进行预处理后，加入150mg载有TiO2的碳纳米管进行光催化实验，经光催化氧化3h后，CODCr去除率达到90％，处理效果非常明显。结果：实验结果表明，该种催化剂具有很好的光催化活性。结论：用Fenton试剂预处理与TiO2光催化联合使用，对含腈废水中的难降解有机物去除效果好，具有一定的实用性。     

水中邻苯二甲酸二丁酯的光催化降解

目的：研究光降解饮用水中邻苯二甲酸二丁酯化合物。方法：水中DBP在紫外光照射下，紫外光和臭氧共同作用下，以及加入纳米TiO2进行光催化降解。结果：紫外光和臭氧共同处理对DBP的降解有协同作用，单紫外光照射的半衰期是10．6min，紫外光与臭氧协同降解的半衰期是7．8min，而光催化的半衰期则小于1min，较小的粒经20～30nm的TiO2光催化效果要好于较大粒经30～50nm的TiO2光催化效果，加入20～30nmTiO2光催化剂的最佳剂量是0．5g／L，初始pH越大越有利于DBP的光催化降解。结论：光催化可有效降解水中邻苯二甲酸二丁酯。     

Photocatalytic reactivity of zinc and cadmium ions in UV-irradiated titania suspensions

The reduction of Zn(II) and Cd(II) species to their corresponding metallic form is characterized by negative reduction potentials in aqueous media. Thus the direct reduction of these species by photogenerated electrons in UV-irradiated titania (Degussa, P 25) suspensions is difficult unless co-additives are present. This paper presents such scenarios involving nitrate and organic additives and describes conditions where facile conversion of Zn(II) and Cd(II) species can be secured. The photocatalysis reaction products depend on the conditions extant in the TiO₂ dispersions and can be either the corresponding oxy-hydroxy compound or the metal. Interesting interfacial changes occur when formate ions are added to a TiO₂ suspension containing Zn(II) species. Such changes were probed by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy.     

Surface characteristics of dental implants: A review

Objectives

During the last decades, several changes of paradigm have modified our view on how biomaterials’ surface characteristics influence the bioresponse. After becoming aware of the role of a certain microroughness for improved cellular contact and osseointegration of dental titanium implants, the likewise important role of surface energy and wettability was increasingly strengthened. Very recently, synergistic effects of nanoscaled topographical features and hydrophilicity at the implant/bone interface have been reported.