TY  - JOUR
A1  - Ugwuja, Chidinma G.
A1  - Adelowo, Olawale O.
A1  - Ogunlaja, Aemere
A1  - Omorogie, Martins O.
A1  - Olukanni, Olumide D.
A1  - Ikhimiukor, Odion O.
A1  - Iermak, Ievgeniia
A1  - Kolawole, Gabriel A.
A1  - Günter, Christina
A1  - Taubert, Andreas
A1  - Bodede, Olusola
A1  - Moodley, Roshila
A1  - Inada, Natalia M.
A1  - Camargo, Andrea S.S. de
A1  - Unuabonah, Emmanuel Iyayi
T1  - Visible-Light-Mediated Photodynamic Water Disinfection @ Bimetallic-Doped Hybrid Clay Nanocomposites
T2  - ACS applied materials & interfaces
N2  - This study reports a new class of photocatalytic hybrid clay nanocomposites prepared from low-cost sources (kaolinite clay and Carica papaya seeds) doped with Zn and Cu salts via a solvothermal process. X-ray diffraction analysis suggests that Cu-doping and Cu/Zn-doping introduce new phases into the crystalline structure of Kaolinite clay, which is linked to the reduced band gap of kaolinite from typically between 4.9 and 8.2 eV to 2.69 eV for Cu-doped and 1.5 eV for Cu/Zn hybrid clay nanocomposites (Nisar, J.; Arhammar, C.; Jamstorp, E.; Ahuja, R. Phys. Rev. B 2011, 84, 075120). In the presence of solar light irradiation, Cu- and Cu/Zn-doped nanocomposites facilitate the electron hole pair separation. This promotes the generation of singlet oxygen which in turn improves the water disinfection efficiencies of these novel nanocomposite materials. The nanocomposite materials were further characterized using high-resolution scanning electron microscopy, fluorimetry, therrnogravimetric analysis, and Raman spectroscopy. The breakthrough times of the nanocomposites for a fixed bed mode of disinfection of water contaminated with 2.32 x 10(7) cfu/mL E. coli ATCC 25922 under solar light irradiation are 25 h for Zn-doped, 30 h for Cu-doped, and 35 h for Cu/Zn-doped nanocomposites. In the presence of multidrug and multimetal resistant strains of E. coli, the breakthrough time decreases significantly. Zn-only doped nanocomposites are not photocatalytically active. In the absence of light, the nanocomposites are still effective in decontaminating water, although less efficient than under solar light irradiation. Electrostatic interaction, metal toxicity, and release of singlet oxygen (only in the Cu-doped and Cu/Zn-doped nanocomposites) are the three disinfection mechanisms by which these nanocomposites disinfect water. A regrowth study indicates the absence of any living E. coli cells in treated water even after 4 days. These data and the long hydraulic times (under gravity) exhibited by these nanocomposites during photodisinfection of water indicate an unusually high potential of these nanocomposites as efficient, affordable, and sustainable point-of-use systems for the disinfection of water in developing countries.
KW  - disinfection
KW  - nanocomposite material
KW  - multidrug-resistant Escherichia coli
KW  - water
KW  - reactive oxygen species
Y1  - 2019
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/48804
SN  - 1944-8244
SN  - 1944-8252
VL  - 11
IS  - 28
SP  - 25483
EP  - 25494
PB  - American Chemical Society
CY  - Washington, DC
ER  -