Water-Active Titanium/Molybdenum/Mixed-Oxides: Removal Efficiency of Organic Water Pollutants by Adsorption and Photocatalysis and Toxicity Assessment

Abstract

A new titanium/molybdenum/mixed-oxides (TMO) contact-type heterojunction photocatalyst was prepared by a simple, low-cost, and environmentally-friendly mixing-calcination solid-state method. A microstructural investigation by scanning electron microscopy (SEM) showsirregularly shaped agglomerated morphology of TMO that consists of firmly connected globular TiO2 and rod-like MoO3 particles. The detailed structure and optical bandgap investigation by X-ray diffraction, Raman, and UV-Vis spectroscopy revealed the TMO’s composition of ~37 wt.% rutile TiO2, ~25 wt.% of anatase TiO2, and ~38 wt.% of molybdite MoO3 phase and an absorption threshold of around 380 nm, which implies more probability of desirable higher visible light absorption. The removal efficiency of pesticides quinmerac (QUI) and tembotrione (TEM), and pharmaceuticals metoprolol (MET), amitriptyline (AMI), ciprofloxacin (CIP),and ceftriaxone (CEF) from water in the presence of starting pure TiO2, MoO3, and prepared TMO were investigated under different pH values and UV irradiation/simulated sunlight (SS). Each starting metal-oxide precursors and prepared TMO showed a different affinity for adsorption of tested pesticides and pharmaceuticals, and, in general, better photocatalytic degradation efficiency under UV irradiation than under simulated sunlight. The highest photocatalytic degradation efficiency under UV irradiation was 81.6% for TEM using TMO; using TiO2 was 65.0% for AMI, and using MoO3 was 79.3% for CEF after 135 min. However, TMO showed a very high synergic adsorption/photocatalytic under-SS efficiency in the removal of CIP of almost 80% and under UV irradiation of 90% CIP removal after 75 min. The toxicity of catalysts, starting compounds, and their intermediates formed during the removal process was assessed using a rat hepatoma cell line (H-4-II-E). The highest hepatotoxic effects were obtained by using UV irradiated QUI and MET suspension with TMO for up to 60 min.

Preparation of BiOCl/Bi2WO6 Photocatalyst for Efficient Fixation on Cotton Fabric: Applications in UV Shielding and Self-Cleaning Performances

“…Nevertheless, the rapid recombination of photogenerated electron-hole pairs in Bi 2 WO 6 reduces its photocatalytic efficiency [12][13][14]. Interestingly, the lattice of Bi 2 WO 6 and BiOCl can be well matched and form heterojunctions to promote the separation of photogenerated carriers [15,16]. Tahmasebi et al fabricated a Bi 2 WO 6 /BiOCl composite through a facile hydrothermal method with the aid of hydrochloric acid (HCl) as a Cl source, and the obtained Bi 2 WO 6 /BiOCl exhibited preferable photocatalytic activity [17].…”

Enhanced Photocatalytic and Photoluminescence Properties Resulting from Type-I Band Alignment in the Zn2GeO4/g-C3N4 Nanocomposites

“…Consequently, in this perspective, the treatment of complex organic pollutants has been prioritized and well regulated by diverse countries. Thus, various strategies have been employed to the treatment of effluent with complex features (e.g., adsorption, biological degradation, membrane separation, photocatalysis, and so on), with more and more researchers paying attention to the development as well as application of heterostructured semiconducting materials-based photocatalysts [5][6][7][8][9][10][11]. Particularly, the photocatalysis has been considered as the most-efficient low-cost strategy to the treatment of effluent, resulting in a fast and non-selective oxidation of diverse pollutants [6,12].…”