TiO2-NPs/ZnO-NPs@Co3O4 nanocomposite from natural extracts for the Rhodamine 6 G photodegradation
Robson Dias Wouters, Daniel Moro Druzian, Pâmela Cristine Ladwig Muraro, Maurício Dalla Costa Rodrigues da Silva, Claudinei dos Santos, Yolice Patricia Moreno Ruiz, André Galembeck, Giovani Pavoski, Denise Crocce Romano Espinosa, William Leonardo da Silva
Abstract
Socio-environmental issues are frequent in industrial growth, especially wastewater containing dyes resulting in toxic effects on fauna and flora. Parallelly, synthesizing nanomaterials using extracts allows for improved properties with fewer environmental effects. In this way, the present study aims to synthesize using natural extracts and characterize a ceramic nanocomposite containing titanium and zinc dioxide doped with tricobalt tetroxide nanoparticles (TiO 2 NPs/ZnO NPs@Co 3 O 4 NPs) for the removal of Rhodamine 6 G under visible radiation. TiO 2 -NPs/ZnO-NPs@Co 3 O 4 -NPs ceramic nanocomposite showed a heterogeneous morphology with a negative charge surface of -16.73 mV, V-type isotherm and H1 hysteresis, surface area (S BET ) of 62.2 m² g −1 , pore diameter (Dp) of 10.41 nm and bang gap energy (Eg) of 2.98 eV. The ideal condition of photocatalytic heterogeneous was of [Rh 6 G] = 3.18 mg L −1 , [NPs] = 1 g L −1 and pH = 7 with 99.97 % for the Rh 6 G photodegradation and the apparent rate of the pseudo first-order reaction ( k ) of 0.0193 min −1 . After IV cycles of TiO 2 -NPs/ZnO-NPs@Co 3 O 4 -NPs, there was a small reduction in Rh 6 G dye removal (99.97 to 85.71 %), confirming the photocatalytic stability of the nanocatalyst. Ecotoxicity tests were carried out with Lactuca sativa seeds and demonstrated root radicular inhibition of 6.41 % to 20.73% ranging from 12.5 - 100 mg L −1 . Machine Learning (ML) study was used to predict the Rh 6 G photodegradation mechanism, where the dye molecules successively cleavage such aromatic structure and carbonic acid to produce smaller fragments that are further form CO 2 and H 2 O. Therefore, ceramic nanocomposite presents potential application as a nanocatalyst for the wastewater treatment.