Ag2O/FACs复合材料的制备及其光催化性能

以经过酸化刻蚀改性的粉煤灰漂珠(FACs)为催化剂载体制备Ag 2O/FACs复合材料。借助SEM、XRD、FTIR、BET等对相关样品的物相结构及微观形貌进行表征,并通过亚甲基蓝(MB)溶液的光降解实验评价了所制复合材料的光催化性能。结果表明,尽管FACs改性前后的结构及化学组成差别不大,但酸化刻蚀处理能有效提高FACs的吸附性能;Ag 2O/FACs复合材料在近红外光条件下对亚甲基蓝溶液的降解率可达97.5%,并具有较高的催化稳定性;Ag 2O光生空穴在降解反应中起到重要作用。

Preparation of Z-scheme WO_3(H_2O)_(0.333)/Ag_3PO_4 composites with enhanced photocatalytic activity and durability

Ag3PO4 is widely used in the field of photocatalysis because of its unique activity. However, photocorrosion limits its practical application. Therefore, it is very urgent to find a solution to improve the light corrosion resistance of Ag3PO4. Herein, the Z-scheme WO3(H2O)0.333/Ag3PO4 composites are successfully prepared through microwave hydrothermal and simple stirring. The WO3(H2O)0.333/Ag3PO4 composites are characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and UV-Vis spectroscopy. In the degradation of organic pollutants, WO3(H2O)0.333/Ag3PO4 composites exhibit excellent performance under visible light. This is mainly attributed to the synergy of WO3(H2O)0.333 and Ag3PO4. Especially, the photocatalytic activity of 15%WO3(H2O)0.333/Ag3PO4 is the highest, and the methylene blue can be completely degraded in 4 min. In addition, the stability of the composites is also greatly enhanced. After five cycles of testing, the photocatalytic activity of 15%WO3(H2O)0.333/Ag3PO4 is not obviously decreased. However, the degradation efficiency of Ag3PO4 was only 20.2%. This indicates that adding WO3(H2O)0.333 can significantly improve the photoetching resistance of Ag3PO4. Finally, Z-scheme photocatalytic mechanism is investigated.

Recovery of valuable elements from spent YBa_2Cu_3O_(7-x)/Agcomposite superconductor bulks

Silver as a highly conductive metal is usually doped in YBa2Cu3O7-x superconductor bulks to improve critical current density of YBa2Cu3O7-x superconductor.The valuable metal elements silver,yttrium,barium and copper in waste YBa2Cu3O7-x/Ag composite superconductor bulks were recovered,respectively.Silver was recovered with process at first,the waste was dissolved by nitric acid and silver chloride was precipitated by adding chloride acid,then silver pig was obtained by melting silver chloride together with sodium carbonate at 1 000℃.The effective factors on recovery ratio and purity of silver were studied.The chemical analysis proves that the purity of silver ingot is 95.86%.The recovery ratio of silver is calculated to be 92.56%.The loss of silver may be due to the loss of silver chloride during filtering and the volatilization of silver when silver chloride and sodium carbonate are smelted at high temperature.For other three metal elements,Y3 +,Ba 2+and Cu 2+,in the surplus waste liquid after recovering silver, they were separated with the sequence of barium,copper and then yttrium step by step.First,sulfate acid was used to precipitate barium sulfate.Then,sodium sulfide was added to the surplus solution so that copper could be separated as copper sulfide.During this separation procedure,it was important to control the pH value to be 1-2.After that,oxalic acid was added into the surplus solution to obtain yttrium oxalate.Finally,yttrium oxide was formed by burning yttrium oxalate.The XRD results indicate that the final products are all single-phase compounds as BaSO4,CuS and Y2O3,respectively.

新型复合光催化剂Cu_(2)O/Ag/Ag_(3)PO_(4)光催化降解甲基橙

采用简单液相法制备Cu_(2)O/Ag/Ag_(3)PO_(4)三元复合光催化材料,并通过XRD、SEM、UV方法进行表征。结果表明,与纯Cu_(2)O相比,三元复合材料Cu_(2)O/Ag/Ag_(3)PO_(4)催化效果明显提高,30 min可以催化70%的污染物。浸泡次数直接影响催化效果,浸泡20次降解90%的甲基橙需要约50 min,远高于浸泡5次和10次的时间。该催化剂为同类光催化复合材料的制备提供了新思路。

ZnFe2O4/Ag3PO4的制备及其可见光催化降解性能的研究

通过微波水热法合成了ZnFe2O4/Ag3PO4复合材料,进行了XRD、红外及紫外-可见漫反射表征。并用含10%ZnFe2O4的复合材料对50 ppm的罗丹明B(Rhodamine B)、甲基橙(Methyl Orange)、亚甲基蓝(Methylene Blue)染料在模拟太阳光的条件下进行光催化降解。实验结果表明:在降解甲基橙(阴离子型染料)2 h后降解率仅达20%,降解亚甲基蓝(阳离子型染料)2 h后降解率达83%,降解罗丹明B(中性分子染料)2 h后的降解率达到了90%以上,表明这一复合材料是非阴离子型光降解催化剂,对中性染料降解效率大于其它离子型染料;而在5%、10%的复合材料对罗丹明B光催化降解中,10%的复合材料2 h的降解率超过90%,5%的复合材料2 h的降解率接近100%.而且复合材料具有良好的磁性能,有利于回收利用。

Structure and Mechanical Properties of Ni-P-Nano Al_2O_3 Composite Coatings Synthesized by Electroless Plating

Ni-P-nano Al2O3 composite coatings were deposited by electroless plating,and their microstructures were observed by SEM（scanning electron microscope）.The microhardness and the wear resistance of the Ni-P-nano Al2O3 composite coatings were measured using microhardness tester and block-on-ring tribometer,respectively,and the comparison with those of Ni-P coatings or Ni-P-micro Al2O3 coating was given.The influences of aging temperature on their hardness and wear resistance were analyzed.The results showed that the nano Al2O3 particles were distributed uniformly in the Ni-P-Al2O3 coatings.Among three kinds of Ni-P based coatings,the hardness and wear resistance of Ni-P-nano Al2O3 coatings were largest,and the maximum values could be obtained at 400 ℃.This indicated that the precipitation of nano Al2O3 particles would improve the hardness and wear resistance of the Ni-P coatings.

Ag复合中空纤维膜的制备与性能

以化学镀法制备了Ag复合中空纤维膜,考察了温度对Ag膜的影响,测试了气体渗透性能。结果表明,化学镀温度45℃时,有利于Ag颗粒在载体上的有效沉积,可以形成连续致密的Ag膜。150~300℃,氧渗透通量随压力和温度的增大而增加,氮气渗透通量逐渐减小。300℃时,O_(2)渗透通量为0.027 mol·m^(-2)·s^(-1)。