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    Palladium nanoparticles stabilized on a novel Schiff base modified Unye bentonite: Highly stable, reusable and efficient nanocatalyst for treating wastewater contaminants and inactivating pathogenic microbes
    (Elsevier B.V., 2020) Sajjadi, Mohaddeseh; Baran, Nuray Yılmaz; Baran, Talat; Nasrollahzadeh, Mahmoud; Tahsili, Mohammadreza; Shokouhimehr, Mohammadreza
    Efficient decoration and characterization of highly catalytic, active Pd nanoparticles (NPs) onto a novel Schiff base modified Unye bentonite (UN-Sch) with high coordination performance of structurally defined 2-pyrrolaldehyde ligands against palladium ions (Pd NPs@UN) have been described. Amine modified UN/Pd NPs were fabricated via a facile multi-step approach without utilizing any additional reducing agents. To check the applicability of the synthesized Pd NPs@UN as highly active nanocatalysts in water and wastewater treatment, the reduction of highly toxic compounds such as 4-nitrophenol (4-NP), hexavalent chromium [Cr(VI)], Rhodamine B (RhB), potassium hexacyanoferrate(III) (K3[Fe(CN)6]) and congo red (CR) at ambient temperature in eco-friendly media has been investigated. The surface nature of Unye bentonite was altered after modification, leading to notable increase in the catalytic properties. The ensuing Pd NPs@UN demonstrated superior catalytic prowess (100% conversion within a few seconds for the aforementioned pollutants), excellent stability (~4 months) and superior recyclability (~96% yield after seven successive cycles). Notably, the present procedure is a clean and green one in which aqueous sodium borohydride (NaBH4) or formic acid (HCOOH) are used as reducing agents in the absence of any toxic reductants. Moreover, the results showed that Pd NPs@UN was effective against fungi and bacteria.
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    Pd nanocatalyst stabilized on amine-modified zeolite: Antibacterial and catalytic activities for environmental pollution remediation in aqueous medium
    (Elsevier B.V., 2020) Nasrollahzadeh, Mahmoud; Baran, Talat; Baran, Nuray Yılmaz; Sajjadi, Mohaddeseh; Tahsili, Mohammadreza; Shokouhimehr, Mohammadreza
    In this study, the immobilization of palladium nanoparticles (NPs) on amine modified zeolite (Zeo) particles bearing a heterocyclic ligand has been developed through immobilizing structurally defined furfural with long tail of 3-aminopropyltriethoxysilane. NH2 modified Zeo/Pd has been synthesized via facile multi-step organic amine functionalization as a sustainable, recoverable and highly active nanocatalyst in the reduction of hexavalent chromium [Cr(VI)], potassium hexacyanoferrate(III) (K3[Fe(CN)6]), 2,4-dinitrophenylhydrazine (2,4-DNPH), 4-nitrophenol (4-NP), Rhodamine B (RhB), Methylene Blue (MB) and Nigrosin (NS) at ambient temperature in aqueous media. The surface nature of zeolite was changed after NH2 modification, leading to a remarkable increase in the catalytic and antimicrobial performances. TEM and HRTEM (high resolution transmission electron microscopy), FESEM (field emission scanning electron microscopy), STEM (scanning transmission electron microscopy), TG-DTG (thermogravimetry/derivative thermogravimetry), FT-IR (Fourier transform infrared), XRD (X-ray diffraction), EDS (energy dispersive X-ray spectroscopy), elemental mapping, XPS (X-ray photoelectron spectroscopy) and Raman analyses have been used to characterize the as-prepared nanocatalyst. The high removal rates of these environmental pollutants with NH2 modified Zeo/Pd nanocatalyst (Pd NPs@Zeo) using sodium borohydride (NaBH4) and formic acid (HCOOH) at ambient temperature were measured via UV–Vis spectroscopy and the nanocatalyst could be reused at least eight times without any significant loss of catalytic activity.