Photocatalytic degradation of malachite green dye by ZnO and ZnO–β-cyclodextrin nanocomposite

2021 ◽  
Vol 44 (4) ◽  
Author(s):  
Renu Yadav ◽  
Tejpal S Chundawat ◽  
Pooja Rawat ◽  
Gyaneshwar K Rao ◽  
Dipti Vaya
Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2033
Author(s):  
Marwa F. Elkady ◽  
Hassan Shokry Hassan

An efficient, environmentally compatible and highly porous, silver surface-modified photocatalytic zinc oxide/cellulose acetate/ polypyrrole ZnO/CA/Ppy hybrid nanofibers matrix was fabricated using an electrospinning technique. Electrospinning parameters such as solution flow rate, applied voltage and the distance between needles to collector were optimized. The optimum homogenous and uniform ZnO/CA/Ppy polymeric composite nanofiber was fabricated through the dispersion of 0.05% wt ZnO into the dissolved hybrid polymeric solution with an average nanofiber diameter ranged between 125 and 170 nm. The fabricated ZnO-polymeric nanofiber was further surface-immobilized with silver nanoparticles to enhance its photocatalytic activity through the reduction of the nanofiber bandgap. A comparative study between ZnO polymeric nanofiber before and after silver immobilization was investigated using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) and thermal gravimetric analysis (TGA). The photocatalytic degradation efficiency of the two different prepared nanofibers before and after nanosilver immobilization for malachite green (MG) dye was compared against various experimental parameters. The optimum degradation efficiency of nanosilver surface-modified ZnO-polymeric nanofibers was recorded as 93.5% for malachite green dye after 1 h compared with 63% for ZnO-polymeric nanofibers.


2021 ◽  
Author(s):  
Anthony Ekennia ◽  
Dickson N. Uduagwu ◽  
Njemuwa N. Nwaji ◽  
Olawale J. Olowu ◽  
Obianuju L. Nwanji ◽  
...  

Abstract We report on hydrothermal synthesis of biogenic silver nanoparticles (AgNPs) using aqueous leaf extract of Alchornea laxiflora for threefold applications in antibacterial screening against Escherichia coli and Staphylococcus aureus, tyrosinase inhibition of mushroom tyrosine enzymes with 3,4-dihydroxyphenylalanine as a substrate and photocatalytic degradation of malachite green dye. The mode of action for the tyrosinase application and kinetics of both the tyrosinase and photocatalytic activities were provided. The localized surface resonance bands of the AgNPs were observed within the range of 424 – 435 nm from the electronic spectral analysis. Fourier transform-infrared studies reveal the functional groups of plant metabolites such as phenolic compounds and amines on the nanoparticles. The Energy Dispersive X-ray result reveals the presence of silver and other elemental compositions from the plant extract. X-ray diffraction result showed a face-centred cubic crystalline structure for the AgNPs. The SEM analyses reveal that the nanoparticles are spherical in shape with average size range of 20-52 nm. The AgNPs exhibited a dose dependent tyrosinase inhibition activity with IC50 of 20.83 µg/ml and a competitive mode of inhibition. The results of photocatalytic degradation of malachite green dye depicted rapid photo inspired degradation of 86 % in less than a min and at reaction rate of 0.136 min-1. The silver nanoparticles showed enhanced antibacterial activities compared to the precursors: silver nitrate and aqueous extract of Alchornea laxiflora.


2020 ◽  
Vol 258 ◽  
pp. 110043 ◽  
Author(s):  
Alaa Magdy Saad ◽  
Mostafa R. Abukhadra ◽  
Sayed Abdel-Kader Ahmed ◽  
Ali M. Elzanaty ◽  
Amr H. Mady ◽  
...  

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