TiO_2纳米管光催化处理络合银:Ag(I)与配体协同机制

Photocatalytic removal of chelated silver by TiO_2 nanotube:synergetic mechanism between Ag(I) and organic ligands

以纳米Ti O2为原料,采用水热合成法制备Ti O2纳米管,以XRD、FT-IR和SEM进行表征。XRD表明Ti O2纳米管主要为锐钛矿相;FT-IR表明制备材料含有丰富的羟基;SEM表明材料分散均匀、不易团聚,比原料具有更大的比表面积。在300 m L/min空气曝气、p H=3、T=(26±0.5)℃和300 W紫外光照的条件下,进行光催化降解EDTA-Ag(I)和DTPA-Ag(I)的实验。结果表明,制备的催化材料对含络合银废水的处理具有较高的光催化活性,金属银的去除率和EDTA、DTPA的降解率都达到95%以上,反应近似符合一级模型;有机配体的光催化氧化与Ag(I)的光催化还原之间具有明显的协同效应。

Ti O2 nanotube was successfully synthesized by the hydrothermal method and characterized by using X-Ray diffraction,FT-IR spectrum and SEM. X-Ray diffraction and FT-IR indicated that Ti O2 nanotube is primarily composed of anatase and contains abundant hydroxyl,respectively. SEM showed that it is uniformly dispersed and less agglomerative with greater surface areas. Photocatalytic removal of chelated silver from wastewater by Ti O2 nanotube was investigated,including Ag（ I）-EDTA and Ag（ I）-DTPA. The results proved that the prepared Ti O2 nanotube has higher catalytic activity for the chelated silver. Under the conditions of aeration（ 300 m L / min）,UV（ 300 W）,T =（ 26 ± 0. 5） ℃,p H = 3. 0,the removal effect of Ag（ I）,DTPA and EDTA is as high as 95% in 1 h. The photocatalytic reaction rate obeys pseudo-first-order kinetic equation. Futhermore,a significant synergistic effect was observed between the reduction of Ag（Ⅰ） and oxidation of organic ligands.