Fundamental studies of solar photocatalytic pathways for valorization of biosolids to fuels and chemicals

随着对气候变化和全球能源和自然资源枯竭的日益关注，迫切需要迅速转向可再生能源和化学品。与此同时，地球上城市人口和现代化的持续激增导致生物固体的产量不断增加，这些生物固体通常作为废物处理。然而，这些生物固体是有机物质的可再生来源，可以转化为能源和有价值的化学品。在加拿大，废水处理厂每年产生超过660，000干吨的生物固体，随着根据加拿大环境部长理事会于2009年批准的《加拿大城市废水排放管理战略》建造新的和升级的设施，这一数量预计还会增加。最近，在2012年，CCME批准了一项新的国家政策，要求有益地利用城市生物固体中的宝贵资源。世界其他地方也出现了类似的趋势。15个欧盟国家的污泥总产量从1984年增加了约50%，2010年达到1000万吨/年，预计到2015年，中国的污水处理厂将产生1000万吨/年的生物固体。因此，通过转化为生物燃料和生物基化学品从生物固体中提取价值将减少浪费，降低温室气体的总排放量。* * 近年来，通过生物质的光催化转化使用太阳能（S2F）生产可运输燃料获得了越来越多的关注和兴趣。虽然太阳能电池在污染物减排和污染物矿化方面已经得到了广泛的研究，但其在以化学键形式储存太阳能方面的应用是新的。在这个项目中，我们的目标是研究太阳能电池板在城市和工业生物固体中的效用。本研究的具体目标是：1）设计新型可见光光催化剂，用于氢气和增值化学品的最佳生产，2）更好地了解太阳能光催化过程的机制和动力学，用于城市和工业生物固体的转化，以及3）设计新型光反应器，以最大限度地收集太阳能。* * 生物固体的太阳能光催化转化有可能从根本上改变废水处理行业，从固体废物中提取价值，提高处理厂的能源效率。该技术将按照CCME的要求改善环境健康，并将有助于加拿大的长期能源供应和安全。它还将帮助加拿大在新兴的低碳经济中保持领先地位，并实现其温室气体排放目标。

With the growing concern over climate change and the global depletion of energy and natural resources, there is a pressing need for rapid shift to renewable sources of energy and chemicals. Meanwhile, the ongoing surge in the planet's urban populations and modernization has resulted in the ever increasing production of biosolids that are often disposed as waste. However, these biosolids are renewable sources of organic matter and can be converted to energy and valuable chemicals. In Canada, wastewater treatment plants produce in excess of 660,000 dry tonnes of biosolids per year and this amount is expected to increase as new and upgraded facilities are constructed under the Canada-wide Strategy for the Management of Municipal Wastewater Effluent ratified by the Canadian Council of Ministers of the Environment (CCME) in 2009. More recently, in 2012, CCME approved a new national policy that requires the beneficial use of valuable resources in municipal biosolids. A similar trend is observed elsewhere in the world. The total sludge production in 15 European Union countries increased by about 50% from 1984 and reached 10 M t/year in 2010, and in China wastewater treatment plants are expected to generate 10 M t/year biosolids by 2015. Therefore, extracting value from biosolids through conversion to biofuels and bio-based chemicals will reduce waste and lower the overall greenhouse gas emissions. ******In recent years, production of transportable fuels using solar energy (S2F) via photocatalytic conversion of biomass has gained increasing attention and interest. Although solar photocatalysis has been studied intensively for pollutant abatement and contaminant mineralization, its application in storing sunlight energy in the form of chemical bonds is new. In this project, we aim to examine the utility of solar photocatalysis in valorizing municipal and industrial biosolids. Specific objectives of this research are: 1) to design novel visible light photocatalysts for the optimum production of hydrogen and value-added chemicals, 2) to develop a better fundamental understanding of mechanisms and kinetics of solar photocatalytic processes for the conversion of municipal and industrial biosolids, and 3) to engineer novel photo-reactors for maximum solar energy harvesting. ******Solar photocatalytic conversion of biosolids has the potential to radically change the wastewater treatment industry by extracting value from solid waste materials and enhancing the energy efficiency of the treatment plant. This technology will result in improving the health of the environment as mandated by CCME and will contribute to the long-term energy supply and security in Canada. It will also help Canada secure a leading position in the emerging low-carbon economy and achieve its greenhouse gas emission targets.**