Water & Wastewater Treatment

www.wwtonline.co.uk | WWT | november 2014 | 29 In the know Getting to grips with catalysis Smart Solutions There is growing interest in the use of catalysis in water treatment, both for treating industrial wastewater and enabling the domestic use of 'grey water' Materials chemistry is a vital enabler of the new advanced materials required for sustainable solutions for society and industry, especially in energy, health and in developing replacements for scarce raw materials. One global grand challenge that materials chemistry can meet is the removal of hazardous substances from wastewater and in ensuring the purity of surface water and groundwater. In many regions across the world, industrial processes and extractive industries are polluting local water supplies, and in the UK, we use drinking-quality water to wash our clothes – in both cases, chemistry can offer smart solutions to improving our environment. One of the partners of the Knowledge Centre for Materials Chemistry is the Cardiff Catalysis Institute (CCI), a centre of excellence for catalysis within the UK, which is leading a number of innovative research projects in this field. What is catalysis and how can it be applied to water treatment? Catalysis is the key component of many chemical processes - from the research lab through to large scale industrial processes. In all cases, a catalyst speeds up a chemical reaction, while remaining chemically unchanged itself. There are o…en John Conti-RamSden DirecTor, KnoWleDge cenTre for maTerials chemisTry (Kcmc) concerns about the excess use of chemicals in any treatment or filtration process - nowhere is this truer than in the treatment of water. Because catalysts are not consumed in chemical reactions, they could offer an environmentally sustainable solution to the growing question of water purity and security. how much commercial interest is there in the use of catalysts? The UK sector is booming - it has been estimated that every £1 spent by industry on catalysts generates more than £800 in value of products. The majority of industrial processes use water as a solvent, reaction or transport medium. And in the processes used by the paint, dye and printing industries, the "The project is currently at the proof- of-concept stage, but eventually, it is hoped that this technology could provide a new 'white good' in the average kitchen." wastewater is laced with organic compounds, such as phenols and acetone. In recent years, catalytic technologies have begun to make their mark on these industries, as an efficient route to eliminating organic pollutants at the end of production processes. What are the latest techniques? The Cardiff Catalysis Institute is developing a solution that combines a long-established technique with an innovative catalytic technology. Called Catalytic Wet Air Oxidation (CWAO), this system can target organics in industrial wastewater and could have broad implications for such processes. CWAO borrows catalyst technology from the automotive industry – it is physically similar to a car's catalytic converter, in which highly-efficient catalysis occurs as high temperature gas streams pass through the catalyst. In CWAO, there is no exhaust gas; instead, the system takes in liquid water contaminated with organic compounds, and air is added. In the catalytic reactor, the organics in the water are then oxidised to produce carbon dioxide and clean water. For those industries which produce organics as a by-product, this process offers a way to not only manage wastewater, but by using air, it also removes the need for an additional chemical oxidising agent. An additional benefit of such a system is that the efficiency of the reaction can be strictly controlled – there is no risk of using too much or too little of the oxidising agent in CWAO - the only concern is the input air pressure. PRof Stan GolunSki co-DirecTor, carDiff caTalysis insTiTuTe (cci) • Catalysis Facts ● Catalysis is an enabling technology that underpins an estimated 80-90% of all manu- factured goods used by society ● Gold is inert in bulk form, but is an efficient, highly-selective catalyst. When used in nano- particle form this makes it cost effective ● Over three million metric tons of h2o2 are produced us- ing an indirect chemical route which produced as much waste as product

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