Exposure Route of TiO2 NPs from Industrial Applications to Wastewater Treatment and Their Impacts on the Agro-Environment

Abstract

The tremendous increase in the production and consumption of titanium dioxide (TiO2) nanoparticles (NPs) in numerous industrial products and applications has augmented the need to understand their role in wastewater treatment technologies. Likewise, the deleterious effects of wastewater on the environment and natural resources have compelled researchers to find out most suitable, economical and environment friendly approaches for its treatment. In this context, the use of TiO2 NPs as the representative of photocatalytic technology for industrial wastewater treatment is coming to the horizon. For centuries, the use of industrial wastewater to feed agriculture land has been a common practice across the globe and the sewage sludge generated from wastewater treatment plants is also used as fertilizer in agricultural soils. Therefore, it is necessary to be aware of possible exposure pathways of these NPs, especially in the perspective of wastewater treatment and their impacts on the agro-environment. This review highlights the potential exposure route of TiO2 NPs from industrial applications to wastewater treatment and its impacts on the agro-environment. Key elements of the review present the recent developments of TiO2 NPs in two main sectors including wastewater treatment and the agro-environment along with their potential exposure pathways. Furthermore, the direct exposure routes of these NPs from production to end-user consumption until their end phase needs to be studied in detail and optimization of their suitable applications and controlled use to ensure environmental safety.

Diverse biotechnological applications of multifunctional titanium dioxide nanoparticles: An up‐to‐date review

“…Recently, nanotechnological approach for wastewater treatment using adsorption and photocatalytic technology has attained tremendous attention owing to its eco‐friendliness, sustainability, cost‐effectiveness, and other effective properties [ 130 ]. Among nanomaterials, TiO 2 ‐based nanomaterials have achieved the core importance because of their unique physical and chemical features, remarkable biocompatibility, strong oxidation, and maximal photocatalytic properties [ 131 , 132 ].…”

Remediation of Fouling on Painted Steel Roofing via Solar Energy Assisted Photocatalytic Self‐Cleaning Technology: Recent Developments and Future Perspectives

“…Titanium dioxide (TiO 2 ) is the most widely used semiconductor photocatalyst in commercial applications. [ 29 ]…”

“…Titanium dioxide (TiO 2 ) is the most widely used semiconductor photocatalyst in commercial applications. [29] A specific amount of photons (hγ) are absorbed by the electrons of TiO 2 molecules in the presence of UV and solar radiation, resulting in excitation of its outermost electrons according to the Planck's equation: E ¼ hγ where E-energy, γ-frequency, and h-Planck's constant (h ¼ 6.626 Â 10-34 Js). [30] Predominantly, the electrons in the 2p orbital of oxygen (valance band of TiO 2 ) are excited and transited into the 3d orbital (conduction band of TiO 2 ) resulting in an electron (e À CB )-hole (h þ VB ) pair.…”

Nanotechnology for Environmental and Biomedical Research

“…It is interesting to note that, having reported values mainly for aquatic ecotoxicity, the most sensitive test turned out to be the algae assay, and the most toxic nanomaterials were composed of silver, reinforcing the impact of the contribution by Mariano et al [4]. The other review, by Zahra et al [10], mainly focused on the aspect of environmental safety, and gave an overview of the potential exposure route of titanium dioxide nanoparticles from industrial applications to wastewater treatment, and the impact of this on the agro-environment. The increasing interest in the role of nanotechnology in nanosafe applications is paralleled in the scientific arena by the extreme need to upgrade our knowledge via the use of nanotechnology in the human health field.…”