Query: Recent developments in photocatalytic water treatment technology

Candidate papers:

abstract: In recent years, semiconductor photocatalytic process has shown a great potential as a low cost, environmental friendly and sustainable treatment technology to align with the "zero" waste scheme in the water/wastewater industry. The ability of this advanced oxidation technology has been widely demonstrated to remove persistent organic compounds and microorganisms in water. At present, the main technical barriers that impede its commercialisation remained on the post recovery of the catalyst particles after water treatment. This paper reviews the recent R&D progresses of engineered photocatalysts, photoreactor systems, and the process optimizations and modellings of the photooxidation processes for water treatment. A number of potential and commercial photocatalytic reactor configurations are discussed, in particular the photocatalytic membrane reactors. The effects of key photoreactor operation parameters and water quality on the photo process performances in terms of the mineralization and disinfection are assessed. For the first time, we describe how to utilize a multi variables optimization approach to determine the optimum operation parameters so as to enhance process performance and photooxidation efficiency. Both photomineralization and photo disinfection kinetics and their modellings associated with the photocatalytic water treatment process are detailed. A brief discussion on the life cycle assessment for retrofitting the photocatalytic technology as an alternative waste treatment process is presented. This paper will deliver a scientific and technical overview and useful information to scientists and engineers who work in this field.
author_names: Meng Nan Chong

Bo Jin

Christopher W K Chow

Christopher P Saint
title: Recent developments in photocatalytic water treatment technology: a review.
venue: Water research
year: 2010

abstract: Visible light responsive photocatalytic technology holds great potential in water treatment to enhance purification efficiency, as well as to augment water supply through the safe usage of unconventional water sources. This review summarizes the recent progress in the design and fabrication of visible light responsive photocatalysts via various synthetic strategies, including the modification of traditional photocatalysts by doping, dye sensitization, or by forming a heterostructure, coupled with p conjugated architecture, as well as the great efforts made within the exploration of novel visible light responsive photocatalysts. Background information on the fundamentals of heterogeneous photocatalysis, the pathways of visible light responsive photocatalysis, and the unique features of visible light responsive photocatalysts are presented. The photocatalytic properties of the resulting visible light responsive photocatalysts are also covered in relation to the water treatment, i.e. regarding the photocatalytic degradation of organic compounds and inorganic pollutants, as well as photocatalytic disinfection. Finally, this review concludes with a summary and perspectives on the current challenges faced and new directions in this emerging area of research.
author_names: Shuying Dong

Jing-lan Feng

Maohong Fan

Yunqing Pi

Limin Hu

Xiao Han

Menglin Liu

Jingyu Sun

Jianhui Sun
title: Recent developments in heterogeneous photocatalytic water treatment using visible light responsive photocatalysts: a review
year: 2015

abstract: The presence of both organic and inorganic pollutants in water due to industrial, agricultural, and domestic activities has led to the global need for the development of new, improved, and advanced but effective technologies to effectively address the challenges of water quality. It is therefore necessary to develop a technology which would completely remove contaminants from contaminated waters. TiO2 (titania) nanocatalysts have a proven potential to treat "difficult to remove" contaminants and thus are expected to play an important role in the remediation of environmental and pollution challenges. Titania nanoparticles are intended to be both supplementary and complementary to the present water treatment technologies through the destruction or transformation of hazardous chemical wastes to innocuous end products, that is, CO2 and H2O. This paper therefore explores and summarizes recent efforts in the area of titania nanoparticle synthesis, modifications, and application of titania nanoparticles for water treatment purposes.
author_names: Mphilisi M Mahlambi

Catherine Jane Ngila

Bhekie B Mamba
title: Recent developments in environmental photocatalytic degradation of organic pollutants: the case of titanium dioxide nanoparticles a review
year: 2015

abstract: Geosmin and 2 methylisoborneol (MIB) are two taste and odour causing compounds commonly encountered in drinking water. The analytical identification and quantification of these important taste and odour compounds is required since they affect the organoleptic properties of drinking water and therefore the consumer perception and acceptability of drinking water. This thesis provides an up to date summary of analytical techniques for their identification and quantification. Furthermore, recent developments in the elimination of these target compounds are overviewed; conventional treatment methods such as coagulation, sedimentation, filtration and chlorination are ineffective and alternative successful methods are being sought. There is potential for new elimination technology to be implemented into water treatment facilities due to consumer demand. TiO2 thin films were produced from a magnetron sputtering technique, along with N TiO2, Mo TiO2 and Er TiO2. All The films were characterised in terms of structure and composition using Scanning electron microscopy (SEM) Raman spectroscopy, X ray diffraction (XRD) ultraviolet visible spectroscopy (UV Vis) X ray photoelectron spectroscopy (XPS) energy dispersive X ray spectroscopy (EDX) and surface profilometry. Nitrogen doped titania (N TiO2) photocatalytic thin films were prepared by reactive magnetron sputter deposition. Nitrogen doping was achieved by the introduction of nitrogen gas as an additional reactive gas during sputtering. There was a distinctive shift of the absorption band in the N TiO2 to longer visible regions of the electromagnetic spectrum. The photocatalytic performance was evaluated by mineralisation of geosmin and MIB. XPS revealed that 1% nitrogen doping resulted in reduction of the band gap energy, enabling 80% degradation of geosmin and MIB under visible light irradiation in 150 minutes. Titanium dioxide nanoparticles and titanium dioxide nanoparticles doped with nitrogen were produced via a sol gel method for direct comparison with the thin films to break down the T&Os, unfortunately many issues arise with using nanoparticles in drinking water treatment as the nanoparticles can leach into the water. A series of erbia doped titania (Er TiO2) thin films photocatalysts were also deposited by powder magnetron sputtering method, this material has never been produced before. Erbia powder precursor ranging from 5 to 12.5 were used to dope the titania films. The amount of erbia present in the TiO2 thin film was determined using inductively coupled plasma mass spectrophotometry (ICP MS) Raman spectroscopy showed that the films were not crystalline and the broad peak positions obtained corresponded to a mixture of anatase and brookite crystalline forms. XPS analysis revealed that erbium was present in the form of an oxide. The experiments demonstrated that geosmin and 2 MIB in aqueous solutions was successfully degraded under visible light 450 nm) using Er TiO2. The results demonstrate successful degradation of geosmin and MIB. These results show the feasibility of utilising the magnetron sputtering technique to grow films for industrial applications in new solar powered elimination technology for implementation in water treatment facilities.
author_names: H Casey
title: Visible light induced photocatalytic decomposition of odorant compounds in drinking water
year: 2017

abstract: The technology of photocatalytic oxidation in protecting the environment has been one of the focuses in the world.The recent developments of TiO2 photocatalyst in the field of polluted water treatment are reviewed systematically in this paper.Immobilization technology of TiO2 photocatalyst and new type photocatalytic reactor are also summarized.
author_names: Liu Qingju
title: Development of TiO_2 Photocatalyst in Polluted Water Treatment
year: 2007

abstract: Abstract TiO2 based photocatalysis has become a viable technology in various application fields such as (waste)water purification, photovoltaics/artificial photosynthesis, environmentally friendly organic synthesis and remediation of air pollution. Because of the increasing impact of bad air quality worldwide, this review focuses on the use and optimization of TiO2 based photocatalysts for gas phase applications. Over the past years various specific aspects of TiO2 photocatalysis have been reviewed individually. The intent of this review is to offer a broad tutorial on (recent) trends in TiO2 photocatalyst modification for the intensification of photocatalytic air treatment. After briefly introducing the fundamentals of photocatalysis, TiO2 photocatalyst modification is discussed both on a morphological and an electronic level from the perspective of gas phase applications. The main focus is laid on recent developments, but also possible opportunities to the field. This review is intended as a solid introduction for researchers new to the field, as well as a summarizing update for established investigators.
author_names: Sammy W Verbruggen
title: TiO2 photocatalysis for the degradation of pollutants in gas phase: From morphological design to plasmonic enhancement
year: 2015

abstract: Abstract Heterogeneous photocatalysis is a versatile, low cost, and environmentally benign treatment technology for a host of pollutants. This chapter considers recent developments in the research and application of heterogeneous photocatalysis for (1) water treatment, (2) air depollution, (3) hydrogen production, (4) hydrocarbon generation, (5) transformation of specific compounds, and (6) applications in construction, as well as in (7) photodynamic therapy. It also deals with photoelectrocatalysts for solar energy conversion and coupling of heterogeneous photocatalysis with other Advanced Oxidation Processes (AOPs) Techniques in photocatalyst powder immobilization and the main factors that affect the photocatalytic process are also described. Finally, a reactor design for photocatalytic application is proposed and prospects for all processes are discussed with the goal of overcoming challenges and stimulating further research into this promising field. Different types of photoreactors are described in relation to their applications.
author_names: Beata Bajorowicz

Marek P Kobylanski

Anna Malankowska

Pawel Mazierski

Joanna Nadolna

Aleksandra Pieczynska

Adriana Zaleska-Medynska
title: Application of metal oxide based photocatalysis
year: 2018

abstract: A light source and a semiconducting material comprise a powerful duo that may offer several photocatalytic applications for environmental remediation; in recent years, photocatalytic disinfection based on sunlight has gained considerable attention as an efficient and sustainable technology to control the population of various microorganisms in several aqueous matrices. This chapter highlights recent developments in the field both from an engineering and a microbiological point of view. Advances in photocatalytic materials include the modification of all time classic titania to perform better in the visible part of the electromagnetic spectrum, as well as synthesize novel catalysts such as silver phosphate or robust Fenton like materials. Measuring disinfection efficiency correctly is critical in designing proper treatment systems. Disinfection kinetics are affected by several factors including reactor configuration, the water matrix, possible synergy with other oxidation processes, the selection of the test microorganism, and, most importantly, the way the population of microorganisms is measured; the latter is crucial since disinfection efficiency can easily be overestimated. All these, alongside the mechanisms of microbial structure destruction upon photocatalytic illumination and the perspectives and constraints of process scale up, are dealt with in this chapter.
author_names: Danae Venieri

Dionissios Mantzavinos
title: Disinfection of Waters/Wastewaters by Solar Photocatalysis
year: 2017

abstract: Nano sized TiO2 photocatalytic water splitting technology has great potential for low cost, environmentally friendly solar hydrogen production to support the future hydrogen economy. Presently, the solar to hydrogen energy conversion efficiency is too low for the technology to be economically sound. The main barriers are the rapid recombination of photo generated electron/hole pairs as well as backward reaction and the poor activation of TiO2 by visible light. In response to these deficiencies, many investigators have been conducting research with an emphasis on effective remediation methods. Some investigators studied the effects of addition of sacrificial reagents and carbonate salts to prohibit rapid recombination of electron/hole pairs and backward reactions. Other research focused on the enhancement of photocatalysis by modification of TiO2 by means of metal loading, metal ion doping, dye sensitization, composite semiconductor, anion doping and metal ion implantation. This paper aims to review the up to date development of the above mentioned technologies applied to TiO2 photocatalytic hydrogen production. Based on the studies reported in the literature, metal ion implantation and dye sensitization are very effective methods to extend the activating spectrum to the visible range. Therefore, they play an important role in the development of efficient photocatalytic hydrogen production.
author_names: Meng Ni

Michael K H Leung

Dennis Yiu Cheong Leung

K Sumathy
title: A review and recent developments in photocatalytic water splitting using TiO2 for hydrogen production
year: 2007

author_names: S Pandey

Kotesh Kumar Mandari

Joonwoo Kim

Misook Kang

Elvis Fosso-Kankeu
title: Recent Advancement in Visible Light Responsive Photocatalysts in Heterogeneous Photocatalytic Water Treatment Technology
year: 2020