Detection And Degradation Of The Hydrophobic Organic Chemicals Using A Novel Surface Enhanced Raman Substrate

As a kind of typical hydrophobic organic chemicals, polybrominated diphenylethers are of high biotoxicity. The biotoxicity has a great harm to immune system and nervous system. Polybrominated diphenylethers in the environment are from the leakage of electronic products and rubber products in the process of using and discarding, the incineration of waste and automobile exhaust emisions. Even worse, polybrominated diphenylethers cannot be degraded under natural conditions. Polybrominated diphenylethers finally enter into the atmosphere, the hydrosphere and the ecosphere with the long term migration. The presence of polybrominated diphenylethers is widespread in the environment. Hence, it is particularly important to find suitable methods to detect and degrade the polybrominated diphenylethers in the environment. Currently, the traditional detecting means of polybrominated diphenylethers are chromatography of gases and liquid chromatography. However, the application of the two traditional methods are restricted due to some disadvantages, such as, requiring complicated pre-treatment process, expensive instrument cost, time consuming and low recovery rate. Therefore, there is an urgent need of a rapid, simple, sensitive and economical detection technology. As a nondestructive detecting technique, Surface enhanced raman scattering shows unique advantages in the detection of hydrophobic organic carbon in the environment.In this study, the Yeast@Au nanoparticles were prepared by the yeast as reducing agent in one-step hydrothermal method. The gold precursor was obtained at high temperature. And then the gold nanoparticles supported by the carbon skeleton were obtained under calcined at high temperature. Au nanoparticles were distributed homogeneously on the surface of the carbon skeleton, which the aggregation of Au nanoparticles was avoided. Rapid detection of BDE-47, flourene and pyrene were achieved with the Yeast@Au as SERS substrate and portable raman instrument. What’s more, Yeast@Au@TiO₂ was synthesized by one step hydrothermal method on the basis of Yeast@Au. Au nanopartiches were distributed on the surface of the TiO₂ homogeneously due to the action of the glutaraldehyde. Degradation of BDE-47 and R6 G both in solution and on the suface of the substrate were studied, combined with the spectrophotometer and the portable raman instrument.A large number of hot spots were produced between adjacent gold nanoparticles. The lowest limitation of BDE-47, flourene and pyrene were 5×10^-8 mol?L^-1, 10^-8 mol?L^-1, 10^-8 mol?L^-1, respectively. This method was proved to be of high sensitivity. SERS peaks of three kinds of pollutants and raman peaks of solid powder of the three pure pollutants were compared. And the variation characteristics of the peak intensity were further analyzed. The linear fitting was carried out with the logarithm of the concentration of BDE-47 solution was X axis and the intensity was Y axis when the 668 cm-1 was chosen as characteristic peak of BDE-47. The R2 was 0.994. This method was proved to be a good way to analyse BDE-47 quantitatively and qualitatively. 50 raman peaks with the same concentration of BDE-47 was analyzed. The five standard deviations were all less than 18%, indicating that the method was of good reproducibility.Titanium dioxide（TiO₂） with regular porous was produced by the hydrolysis of titanium isopropoxide. Au nanoparticles were distributed uniformly on the surface of TiO₂. Due to the TiO₂, Yeast@Au@TiO₂ showed better photocatalytic activity. In this study, a method to degrade BDE-47 and R6G both in solutions and on the surface of the substrate was established. 80 percent of pollutants were degraded after the degradation was conducted 1 h, illustrating Yeast@Au@TiO₂ can be used to degrade R6 G and BDE-47. What’s more, Yeast@Au@TiO₂ can be recovered and reused.In summary, we established a new method for the detection the degradation of hydrophobic organic pollutants. The method not only has high sensitivity and reproducibility, but also is simple, convenient and time-saving. It is expected to be an effective method for the emergency and local analysis of pollutant.