Polyaniline nanofibers: acute toxicity and teratogenic effect on Rhinella arenarum embryos

The fate and effect of nanomaterials in the environment is of paramount importance towards the technological application of the materials. This work shows the ecotoxicological potential of polyaniline (PANI) nanofibers in the larvae Rhinella arenarum by means of AMPHITOX test. Acute toxicity of PANI nanofibers towards embryos of the common South American toad R. arenarum (Anura: bufonidae) was evaluated in the premetamorphosis (stage 25) larvae. The exposure of R. arenarum larvae to at dose of 150, 250 and 400 mg L⁻¹ resulted in 100% viability within 96 h exposure. The embryos at 2-4 blastomers stage (early life stage teratogenic test) revealed that embryos were not killed and no teratogenic effects were observed when embryos were incubated with PANI nanofibers (150 and 250 mg L⁻¹), while only a growth retardation of embryos was induced at levels of 250 mg PANI nanofibers L⁻¹. On the other hand, at 400 mg L⁻¹ concentration, a reduction in the body length of larvae and tail malformation was observed. This results suggest that a concentration-dependent toxicity is operative, typified by phenotypes that had abnormal body axes. The presence of PANI nanofibers in gut contents and its excretion by larval stages of R. arenarum was confirmed by UV-visible spectroscopy.     

纳米TiO2-xNx催化剂的制备及其活性研究

以钛酸丁酯为前驱物、无水乙醇作溶剂、二乙醇胺作为抑制剂,采用溶胶-凝胶法制备TiO2溶胶,在NN3气流中直接进行热处理,制备一系列不同焙烧温度的淡黄色的掺氮纳米TiO2粉体。经XRD、UV-Vis和FTIR分析表明,实验制得的TiO2-xNx在350、400、450、500和550℃热处理3 h后仍为锐钛型;450℃保温3 h掺氮样品具有最佳的紫外-可见光响应,其吸收边红移至720 nm左右。罗丹明B的可见光降解实验及产物分析表明,掺氮样品具有良好的可见光催化活性。     

可见光催化剂BiVO_4 降解废水中直接耐酸大红4BS

以直接耐酸大红4BS模拟染料废水为目标污染物,研究了BiVO_4对直接耐酸大红4BS(简称4BS)的吸附效果以及废水初始质量浓度、废水pH和BiVO_4的加入量对光催化降解效果的影响.实验结果表明:当废水初始质量浓度为40 mg/L、废水pH为6.38、BiVO_4加入量为1.0 g/L时,4BS的降解率可达98.9%;BiVO_4重复使用5次后4BS的降解率可达80.0%以上;COD的变化趋势说明4BS被催化剂吸附和光催化降解的过程是循序渐进的.     

某枪用铝合金阳极氧化膜变色行为及对策研究

为了提高某枪外观性能,解决机匣在使用过程中的变色问题,对机匣铝合金阳极氧化原工艺、改进工艺进行了环境试验研究、环境适应性评价.针对枪械的使用环境,主要选择江津和万宁试验站户外暴露的试验方式及实验室模拟环境加速试验的方法研究铝合金机匣耐光性及变色原因.试验结果显示,原有机着色工艺耐光性较差,其变色的主要原因是光辐射作用使膜内着色有机染料的主要发色基"一N-N一"发生了断裂,而改进的金属盐电解着色工艺在试验中未发生变色,能有效解决铝合金机匣的变色问题.     

Fenton氧化法处理石化含油废水生化出水

采用Fenton氧化法处理石化含油废水生化出水,通过正交实验和单因素实验优化了反应工艺条件。正交实验得到各因素对COD去除率的影响大小顺序为:溶液初始pHH_2O_2投加量n(H_2O_2)∶n(Fe~(2+))反应温度。实验最佳工艺条件为:初始溶液pH 4.0,H_2O_2投加量3.00 mL/L,n(H_2O_2)∶n(Fe~(2+))=10,反应温度35℃,反应时间60 min。在此最佳工艺条件下COD可降至60.33 mg/L,COD去除率达61.33%。在最佳工艺条件下,分别采用超声(US)-Fenton氧化和紫外光(UV)-Fenton氧化技术处理含油废水生化出水,COD去除率分别达76.77%和80.23%。但单一Fenton氧化、US-Fenton氧化和UV-Fenton氧化工艺对NH_3-N的去除效果均并不明显。     

Preparation, characterization, and photocatalytic activities of boron- and cerium-codoped TiO2

Boron- and cerium-codoped TiO2 photocatalysts were synthesized using modified sol-gel reaction process and characterized by X- ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, particle size distribution （PSD）, diffuse reflectance spectra （DRS）, and Brunauer-Emmett-Teller （BET）. The photocatalytic activities were evaluated by monitoring the degradation of dye Acid Red B （ARB）. The results showed that the prepared photocatalysts were mixed oxides mainly consisting of titania, ceria, and boron oxide. The structure of TiO2 could be transformed from amorphous to anatase and then to rutile by increasing calcination temperature; the transformation being accompanied by the growth of particle size without any obvious change in phase structure of CeO2. The XPS of B1.6Ce1.0-TiO2 prepared at 500℃ showed that a few boron atoms were incorporated into titania and ceria lattice, whereas others existed as B2O3. Cerium ions existed in two states, Ce^3＋ and Ce^4＋, and the atomic ratio of Ce^3＋/Ce^4＋ was 1.86. When boron and cerium were doped, the UV-Vis adsorption band wavelength showed an obvious shift toward the visible range （〈526 nm）. As the atomic ratio of Ce/Ti increased to 1.0, the absorbance edge wavelength increased to 481 nm. The absorbance edge wavelength decreased for higher cerium doping levels （Ce/Ti=2.0）. The particles size ranged from 122 to 255 nm with a domain at 168 nm （39.4%）. The degradation of ARB dye indicated that the photocatalytic activities of boron- and cerium-codoped TiO2 were much higher than those of P25 （a standard TiO2 powder）. The activities increased as the boron doping increased, whereas decreased when the Ce/Ti atomic ratio was greater than 0.5. The optimum atomic ratio of B/Ti and Ce/Ti was 1.6 and 0.5, respectively.     

饮用水中内分泌干扰物阿特拉津UV光氧化研究

采用单独紫外光氧化工艺去除饮用水中低浓度阿特拉津,研究了不同影响因素对阿特拉津降解效果的影响,并分析了阿特拉津的降解机理.结果表明:单独紫外光氧化对阿特拉津有很好的去除效果,在光强为205μW/cm²条件下,光解120min后,阿特拉津去除率为92.38%.阿特拉津的光解过程符合一级反应动力学模型.通过提高紫外照射光强,可以在短时间内提高阿特拉津的去除率.阿特拉津的初始浓度对光解反应基本没有影响.自来水中的有机物及多种离子的存在会降低阿特拉津的光解速率.紫外光氧化阿特拉津主要降解途径是脱氯反应,反应速率很快.羟基化产物(OHA)是主要的中间产物.OHA在紫外光作用下可以继续发生脱烷基反应,生成OHDIA和OHDEA,反应速率非常缓慢.反应液中pH值的变化与中间产物的形成过程有很好的相关性.     

不同光照条件对8种沉水植物生长的影响

通过研究太湖流域主要沉水植物苦草、密刺苦草、黑藻、穗花狐尾藻、蓖齿眼子菜、微齿眼子菜、马来眼子菜和金鱼藻在3种不同光照条件(100%自然光、55%自然光和15%自然光)下的生长状况,探讨沉水植物对光照条件的适应性。结果表明,苦草、黑藻在55%自然光中相对生长速率最大,金鱼藻随着光照减弱,相对生长速率增加,其余6种植物则与金鱼藻相反。黑藻和穗花狐尾藻在15%自然光条件下分株数显著减少,最大株高明显增大,马来眼子菜最大株高显著减少。在不同光照组条件下8种沉水植物中叶绿素含量及可溶性糖含量基本无明显差异,但淀粉含量变化趋势不稳定。     

硝酸根对水体中甲基汞光化学降解的影响

为研究硝酸根(NO3-)对水体中甲基汞(MMHg)光化学降解的影响,采用室内模拟试验,验证了不同波长光照条件下,NO3-在MMHg光化学反应中的作用,探讨了NO3-浓度对MMHg光解速率及产物的影响,并根据溶液中Hg2+的浓度分析了MMHg光解反应的进行程度.结果表明,在自然光(NL)和紫外光(UV)条件下,只加入了NO3-的处理MMHg光降解速率分别为0.10、0.046 L.(ng·h)-1,Hg0的释放通量分别为1.05、1.27 ng,Hg2+的最终浓度分别为16.97、28.92 ng·L-1;在未加入NO3-和加入了C6H5COOH的条件下,MMHg的剩余浓度相差不大,其光降解速率也分别在0.052、0.015 L.(ng·h)-1左右,Hg0的释放通量分别为23.81、15.38 ng,Hg2+的浓度均小于10 ng·L-1,且呈现先增加后减小趋势.在可见光(VL)照射下,各处理下MMHg的光降解速率无显著性差异(P=0.56),为0.003 L.(ng·h)-1左右,Hg0的释放通量均为5 ng左右,Hg2+的浓度未超过3 ng·L-1,也呈现出先增加后减小的趋势.在NL条件下,随浓度NO3-的增加,MMHg的光降解速率也增加,且各处理间存在显著性差异(P<0.05),Hg0的生成量随NO3-浓度的增加而减少,而Hg2+的浓度也随NO3-浓度的增加而增加.可见在有紫外光的条件下,NO3-对MMHg光降解反应历程、反应速率以及产物有重要影响.     

掺杂镧硼TiO_2光催化剂的制备及可见光活性研究

采用溶胶一凝胶法,制备新型La3+/B/TiO2光催化剂,使用氙灯为光源研究了催化剂光降解甲基橙溶液的催化活性。结果表明,当掺杂0.05%La3+,2.0%B,在500℃下焙烧2 h时,所得催化剂对甲基橙具有最高的光催化活性,与单一的TiO2和单独La3+或者B掺杂的光催化剂比较,La3+/B/TiO2具有相对较高的催化活性。