RESUMO
No disponible
Assuntos
Humanos , Masculino , Feminino , Ruído/efeitos adversos , Ruído/prevenção & controle , Unidades de Terapia Intensiva/organização & administração , Unidades de Terapia Intensiva/normas , Luz/efeitos adversos , Poluentes Ocupacionais do Ar/efeitos adversos , Poluentes Ocupacionais do Ar/efeitos da radiação , Exposição Ambiental/efeitos adversos , Exposição Ambiental/prevenção & controleRESUMO
A highly active photocatalyst, silver loaded mesoporous WO(3), was successfully synthesized by an ultrasound assisted insertion method. The photodegradation of a common air pollutant acetaldehyde was adopted to evaluate the photocatalytic performance of the as-prepared sample under visible-light irradiation. The photocatalytic activity was about three and six times higher than that of pure mesoporous WO(3) and nitrogen-doped TiO(2), respectively. The photocatalytic mechanism was investigated to understand the much enhanced photocatalytic activity, which was mainly attributed to the largely improved electron-hole separation in the Ag-WO(3) heterojunction.
Assuntos
Acetaldeído/química , Poluentes Ocupacionais do Ar/química , Luz , Óxidos/química , Compostos de Prata/química , Tungstênio/química , Acetaldeído/efeitos da radiação , Poluentes Ocupacionais do Ar/efeitos da radiação , Dióxido de Carbono/química , Dióxido de Carbono/metabolismo , Catálise , Microscopia Eletrônica de Transmissão , Nanopartículas , Oxirredução , Óxidos/efeitos da radiação , Fotoquímica , Porosidade , Compostos de Prata/efeitos da radiação , Titânio/química , Tungstênio/efeitos da radiação , Difração de Raios XRESUMO
Sonochemical elimination of organic pollutants can take place through two degradation pathways. Molecules with relatively large Henry's law constants will be incinerated inside the cavitation bubble, while nonvolatile molecules with low Henry's law constants will be oxidised by the OH(*) ejected from the bubble of cavitation. Taking bisphenol-A as a model pollutant, this study points out an alternate degradation route, mediated by bicarbonate ions, which is significant for the elimination of micro-pollutants at concentrations present in natural waters. In this process, OH(*) radicals react with bicarbonate ions to produce the carbonate radical, which, unlike the OH(*) radical, can migrate towards the bulk of the solution and therefore induce the degradation of the micro-pollutants present in the bulk solution. As a consequence, initial degradation rate is increased by a factor 3.2 at low concentration of bisphenol-A (0.022 micromol l(-1)) in presence of bicarbonate in water.
