Photocatalytic Materials Obtained from E-Waste Recycling: Review, Techniques, Critique, and Update

Abstract

Waste-derived materials obtained from the recovery and recycling of electronic waste (e-waste) such as batteries and printed circuit boards have attracted enormous attention from academia and industry in recent years, especially due to their eco-friendly nature and the massive increment in e-waste due to technological development. Several investigations in the literature have covered the advances achieved so far. Meanwhile, photocatalytic applications are especially of interest since they maintain mutual benefits and can be used for H2 production from solar water splitting based on semiconductor processing as a proper environmentally friendly technique for solar energy conversion. In addition, they can be utilized to degrade a variety of organic and non-organic contaminations. Nonetheless, to the best of the authors’ knowledge, there has not been any comprehensive review that has specifically been focused on e-waste-derived photocatalytic materials. In this regard, the present work is dedicated to thoroughly discussing the related mechanisms, strategies, and methods, as well as the various possible photocatalysts synthesized from e-wastes with some critiques in this field. This brief overview can introduce modern technologies and promising possibilities for e-waste valorization, photocatalytic processes, and new photocatalytic degradation methods of eco-friendly nature. This paper discusses various e-waste-obtained photocatalytic materials, synthesis procedures, and applications, as well as several types of e-waste, derived materials such as TiO2, ZnO, indium tin oxide, and a variety of sulfide- and ferrite-based photocatalytic materials.

Titanium Dioxide as the Most Used Photocatalyst for Water Purification: An Overview

“…Additionally, the orthorhombic TiO 2 brookite bandgap energy has been experimentally determined to be 3.1-3.4 eV. This is a biaxial material with three independent components other than the dielectric tensor of the uniaxial rutile and anatase materials [5,28]. The significant value of the energy gap limits the exceptional photocatalytic characteristics of TiO 2 .…”

“…As soon as it was determined that semiconductors could be efficiently used for obtaining products such as H 2 and O 2 , they were also recognized as efficient photocatalysts for degrading toxic materials. Titanium dioxide (TiO 2 ) is the most prominent photocatalyst [1][2][3], widely employed due to its great photocatalytic activity, chemical and biological stability, insolubility in water, acid and base environment, resistivity towards corrosion, nontoxicity, low price, and availability in comparison to oxide, sulfide, and other materials [4][5][6]. Heterogeneous photocatalytic oxidation of organic compounds in an aqueous solution in the presence of TiO 2 as photocatalyst provides the opportunity for efficient treatment of waste, drinking, surface, and ground waters, as well as for obtaining the ultraclean water suitable for the pharmaceutical industry and microelectronics.…”

Review of TiO2 as Desulfurization Catalyst for Petroleum

“…By diving into its one-of-a-kind qualities, synthesis processes, and the novel modification strategies that boost its efficacy in removing sulfur from petroleums, this study offers a complete investigation of the function that titanium dioxide (TiO 2 ) plays as a catalyst for desulfurization [4]. The relevance of titanium dioxide in this field is derived from the fact that it has remarkable photocatalytic characteristics, strong stability, and is safe for the environment [5]. In spite of this, the use of titanium dioxide in the desulfurization of petroleum goes beyond the photocatalytic capabilities that it has on its own [6].…”