4286-23-1Relevant articles and documents
Preparation of nitrogen doped K2Nb4O11 with high photocatalytic activity for degradation of organic pollutants
Qiu, Yongfu,Wang, Lei,Leung, Chi-Fai,Liu, Guijian,Yang, Shihe,Lau, Tai-Chu
, p. 23 - 30 (2011)
Nitrogen doped K2Nb4O11 (K 2Nb4O11-N) has been prepared by solid state reaction between K2Nb4O11 and urea at 400 °C. K2Nb4O11-N has been characterized by XRD, SEM, XPS and UV/vis diffuse reflectance. The photodegradation of various organic pollutants in water by this material, including Orange G (OG), bisphenol A (BPA) and pentachlorophenol (PCP) have been studied at λ > 330 nm and >399 nm. The results show that the photocatalytic activity of K 2Nb4O11-N at >399 nm is higher than those of K2Nb4O11 and Degussa TiO2 P25, indicating the activating effect of nitrogen doping. A mechanism for the photodegradation of organic substrates by K2Nb4O 11-N is proposed.
Oxidative degradation of toxic organic pollutants by water soluble nonheme iron(iv)-oxo complexes of polydentate nitrogen donor ligands
Jana, Rahul Dev,Munshi, Sandip,Paine, Tapan Kanti
, p. 5590 - 5597 (2021/05/04)
The ability of four mononuclear nonheme iron(iv)-oxo complexes supported by polydentate nitrogen donor ligands to degrade organic pollutants has been investigated. The water soluble iron(ii) complexes upon treatment with ceric ammonium nitrate (CAN) in aqueous solution are converted into the corresponding iron(iv)-oxo complexes. The hydrogen atom transfer (HAT) ability of iron(iv)-oxo species has been exploited for the oxidation of halogenated phenols and other toxic pollutants with weak X-H (X = C, O, S,etc.) bonds. The iron-oxo oxidants can oxidize chloro- and fluorophenols with moderate to high yields under stoichiometric as well as catalytic conditions. Furthermore, these oxidants perform selective oxidative degradation of several persistent organic pollutants (POPs) such as bisphenol A, nonylphenol, 2,4-D (2,4-dichlorophenoxyacetic acid) and gammaxene. This work demonstrates the utility of water soluble iron(iv)-oxo complexes as potential catalysts for the oxidative degradation of a wide range of toxic pollutants, and these oxidants could be considered as an alternative to conventional oxidation methods.
Novel synthesis of Ag decorated TiO2 anchored on zeolites derived from coal fly ash for the photodegradation of bisphenol-A
Hlekelele, Lerato,Franklyn, Paul J.,Dziike, Farai,Durbach, Shane H.
supporting information, p. 1902 - 1912 (2018/02/09)
The disposal of millions of tons of coal fly ash (CFA) threatens the environment, hence means to reuse CFA are highly sought after. In this study, CFA was reused to make materials which were tested for water purification. Zeolitic material (CFA-Zeo) was derived from CFA by a 2-step alkali-fusion hydrothermal method and then composited with TiO2 nanoparticles using a novel resin-gel technique. CFA-Zeo loadings were 15 and 30 wt% in the resulting TiO2/CFA-Zeo composites. These composites were then loaded with 1 wt% Ag nanoparticles by a deposition-precipitation technique using NaOH and urea. CFA-Zeo rods (morphology confirmed by TEM) were confirmed by PXRD to be sodium aluminum silicate hydrate. TEM analyses of the CFA-Zeo rods in the composites revealed them to be completely coated with TiO2 nanoparticles that had Ag nanoparticles on their surfaces. The photoluminescence emission peak of TiO2 was found to be significantly higher than that of TiO2/CFA-Zeo composites, with the TiO2/CFA-Zeo composites that were loaded with Ag having even lower emission intensities. UV-vis DRS spectra showed that CFA-Zeo had no effect on the band gap of TiO2, while composites that contained Ag had a wide absorption band in the visible region. The photocatalytic efficiency of these materials was then determined using bisphenol-A (BPA) as a model compound under both UV and visible light. Except for the 30 wt% TiO2/CFA-Zeo composites without Ag, all of the composites had superior photoactivity to uncomposited TiO2 under both UV and visible light. On the other hand, composites with Ag nanoparticles showed the best photoactivities. The superior photoactivities of these composites under UV-light were mainly attributed to the separation of charge carriers, whereas under visible light it was attributed to the ability of silver to harvest visible light through surface plasmon resonance (SPR).
Multienzyme One-Pot Cascade for the Stereoselective Hydroxyethyl Functionalization of Substituted Phenols
Payer, Stefan E.,Pollak, Hannah,Schmidbauer, Benjamin,Hamm, Florian,Juri?i?, Filip,Faber, Kurt,Glueck, Silvia M.
, p. 5139 - 5143 (2018/09/13)
The operability and substrate scope of a redesigned vinylphenol hydratase as a single biocatalyst or as part of multienzyme cascades using either substituted coumaric acids or phenols as stable, cheap, and readily available substrates are reported.
