RESUMEN
Surface interactions with pollutants and photons are key factors that affect the applications of TiO2 in environmental remediation. In this study, the solubilizing agents dimethylsulfoxide and polyoxyethylene sorbitan monooleate, which act as photon competitors, had no effect on the photocatalytic activity of TiO2-C-Ag film in phenanthrene (PHE) removal. Fiberglass with TiO2-C-Ag coating removed 91.1 ± 5.2 and 99.7 ± 0.4% of PHE in treatments using UVA (365-465 nm) and UVC (254 nm) irradiation, respectively. The use of fiberglass as a support increased the superficial area, thus allowing PHE sorption. C and Ag, which are electrically active impurities in TiO2, enhanced its photocatalytic activity and thus the attraction of the pollutant to its surface. The use of high-frequency UV light (UVC) decreased the amount of carbon species deposited on the TiO2CAg film surface. X-ray photoelectron spectroscopy of the TiO2-C-Ag film revealed extensive oxidation of the carbon deposited on the film under UVC light and loss of electrons from Ag clusters by conversion of Ag0 to Ag3+.
Asunto(s)
Carbono/química , Vidrio/química , Fenantrenos/análisis , Plata/química , Titanio/química , Contaminantes Químicos del Agua/análisis , Purificación del Agua/métodos , Adsorción , Carbono/efectos de la radiación , Catálisis , Dimetilsulfóxido/química , Vidrio/efectos de la radiación , Oxidación-Reducción , Espectroscopía de Fotoelectrones , Fotones , Polisorbatos/química , Plata/efectos de la radiación , Solubilidad , Soluciones , Propiedades de Superficie , Titanio/efectos de la radiación , Rayos UltravioletaRESUMEN
A 2(III)(7-3) fractional factorial experimental design was used to establish 16 culture media, with and without PCBs to enhance the activities of laccase (Lac), manganese peroxidase (MnP), and versatile peroxidase (VP) produced by the white rot fungus Pleurotus ostreatus. The culture was added to 10,000 mg L(-1) of transformer oil, containing 71% of the identified Arochlor 1242. The culture conditions were established with eight variables at two values (levels); pH (4 and 6), agitation (100 and 200 rpm), CuSO(4) (150 and 250 mg L(-1)), MnSO(4) (50 and 200 mg L(-1)), Tween 80 (13 and 3500 mg L(-1)), wheat straw (0 and 2.5 g L(-1)), sugarcane bagasse (0 and 2.5 g L(-1)),and Arochlor 1242 (0 and 7100 mg L(-1)) at 4, 8, 12, 16 and 20 days old culture. Laccase activity was enhanced at a high value of pH and low value of agitation (P<0.001) and correlated positively (R(2)= 0.9; α=0.05) with the removal of polychlorinated biphenyls (PCBs). VP activity was enhanced 27-fold with PCBs, Tween 80 and pH. The MnP activity was increased 1.2-fold with PCBs. The fractional factorial experimental design methodology allowed us to determine the P. ostreatus culture media conditions to enhance Lac and VP activities for efficient removal of Arochlor 1242 (one of the most recalcitrant organochloride pollutants). The factors that shown the greatest effect on Lac activity were: pH, agitation and high concentrations of Arochlor 1242.
Asunto(s)
Medios de Cultivo/química , Contaminantes Ambientales/metabolismo , Lacasa/metabolismo , Peroxidasa/metabolismo , Peroxidasas/metabolismo , Pleurotus/enzimología , Bifenilos Policlorados/metabolismo , Arocloros/metabolismo , Biodegradación Ambiental , Concentración de Iones de Hidrógeno , Modelos Lineales , Modelos Químicos , Factores de TiempoRESUMEN
HPLC-UV, (1)H NMR, (13)C NMR, and (1)H-(1)H COSY analyses revealed that exogenous capsaicin was specifically converted into 5,5'-dicapsaicin by both cell suspension cultures of Capsicum annuum var. annuum (chili Jalapeño chigol) and their soluble and NaCl-extracted cell wall protein fractions under oxidative conditions. In cell suspension cultures 5,5'-dicapsaicin was found only in biomass of capsaicin-fed cultures. This compound has not been detected before either in fresh fruits or in in vitro cultures of Capsicum. The transformation of capsaicin by different protein fractions revealed that most of the enzymatic activity was located in the NaCl-extracted, or ionic cell wall bound, protein, and that it was strictly dependent on H(2)O(2). These results might in part explain some previously described features of capsaicin production by in vitro cultures of Capsicum. The implications of the results regarding the catabolism of capsaicinoids are discussed.