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.
Degradation of bisphenol A and acute toxicity reduction by different thermo-tolerant ascomycete strains isolated from arid soils
Mtibaà, Rim,Olicón-Hernández, Dario Rafael,Pozo, Clementina,Nasri, Moncef,Mechichi, Tahar,González, Jesus,Aranda, Elisabet
, p. 87 - 96 (2018/03/21)
Four different laccase-producing strains were isolated from arid soils and used for bisphenol A (BPA) degradation. These strains were identified as Chaetomium strumarium G5I, Thielavia arenaria CH9, Thielavia arenaria HJ22 and Thielavia arenaria SM1(III) by internal transcribed spacer 5.8 S rDNA analysis. Residual BPA was evaluated by HPLC analysis during 48 h of incubation. A complete removal of BPA was observed by the whole cell fungal cultures within different times, depending on each strain. C. strumarium G5I was the most efficient degrader, showing 100% of removal within 8 h of incubation. The degradation of BPA was accompanied by the production of laccase and dye decolorizing peroxidase (DyP) under degradation conditions. The presence of aminobenzotriazole (ABT) as an inhibitor of cytochrome P450s monooxygenases (CYP) demonstrated a slight decrease in BPA removal rate, suggesting the effective contribution of CYP in the conversion. The great involvement of laccase in BPA transformation together with cell-associated enzymes, such as CYP, was supported by the identification of hydroxylated metabolites by ultra-high performance liquid chromatography-mass spectroscopy (UHPLC-MS). The metabolic pathway of BPA transformation was proposed based on the detected metabolites. The acute toxicity of BPA and its products was investigated and showed a significant reduction, except for T. arenaria SM1(III) that did not caused reduction of toxicity (IC50 8%), possibly due to the presence of toxic metabolites. The results of the present study point out the potential application of the isolated ascomycetes in pollutant removal processes, especially C. strumarium G5I as an efficient degrader of BPA.
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).
