Lima A T, Ottosen L M, Ribeiro A B
Department of Sciences and Environmental Engineering, Faculty of Sciences and Technology, New University of Lisbon, 2829-516 Caparica, Portugal.
J Hazard Mater. 2009 Jan 30;161(2-3):1003-9. doi: 10.1016/j.jhazmat.2008.04.046. Epub 2008 Apr 22.
Biomass, such as wood and straw, is currently used in EU as a renewable energy source for energy production and this application is expected to rise in coming years. Combined heat and power installations produce fly ash, which is considered hazardous waste. The fly ash management issue should be addressed before biomass combustion is considered a truly sustainable technology. The electrodialytic process is a remediation technique able to assist the management of fly ash. For this work, straw and co-combustion of wood ash are briefly characterized and their electrodialytic treatment is carried out under acidic conditions. Straw ashes presented high removal rates for Ca, Cu, Cr and particularly for Cd, which has been reduced to a level bellow the established by Danish regulations. Acidification also induced a high dissolution and a lower pH of the ash. Fly ash from co-combustion of wood presents similarities with wood ash alone. However, further characterization should be carried out before any comparison regarding applicable legislation. Under acidic conditions, the electrodialytic treatment was not effective for the co-combustion wood ash. The heavy metals appeared in the least soluble fraction of this ash and lowering the pH of such an alkaline material does not mean sustainability and may hinder its reuse.
生物质，如木材和秸秆，目前在欧盟被用作能源生产的可再生能源，预计未来几年这种应用还会增加。热电联产装置会产生粉煤灰，而粉煤灰被视为危险废物。在将生物质燃烧视为真正可持续的技术之前，应先解决粉煤灰管理问题。电渗析工艺是一种能够辅助粉煤灰管理的修复技术。在这项工作中，简要描述了秸秆和木灰的混合燃烧情况，并在酸性条件下对其进行了电渗析处理。秸秆灰对钙、铜、铬尤其是镉的去除率很高，镉已降至丹麦法规规定的水平以下。酸化还导致灰分的高溶解和较低的pH值。木材混合燃烧产生的粉煤灰与单独的木灰有相似之处。然而，在进行任何有关适用法规的比较之前，应进一步进行特性分析。在酸性条件下，电渗析处理对木材混合燃烧产生的粉煤灰无效。重金属存在于这种灰分中溶解度最低的部分，降低这种碱性物质的pH值并不意味着可持续性，可能会阻碍其再利用。
