Department of Civil Engineering, Technical University of Denmark, Denmark.
J Hazard Mater. 2013 Apr 15;250-251:212-9. doi: 10.1016/j.jhazmat.2013.02.004. Epub 2013 Feb 10.
Due to relatively high concentrations of Cd, biomass combustion fly ashes often fail to meet Danish legislative requirements for recycling as fertilizer. In this study, the potential of using electrodialytic remediation for removal of Cd from four different biomass combustion fly ashes was investigated with the aim of enabling reuse of the ashes. The ashes originated from combustion of straw (two ashes), wood chips, and co-firing of wood pellets and fuel oil, respectively. A series of laboratory scale electrodialytic remediation experiments were conducted with each ash. The initial Cd concentration in the ashes varied between 8.8 mg Cd/kg (co-firing ash) and 64 mg Cd/kg (pre-washed straw ash), and pH varied from 3.7 (co-firing ash) to 13.3 (wood ash). In spite of such large variations between the ashes, the electrodialytic method showed to be sufficiently robust to treat the ashes so the final Cd concentration was below 2.0mg Cd/kg DM in at least one experiment done with each ash. This was obtained within 2 weeks of remediation and at liquid to solid (L/S) ratios of L/S 16 for the pre-washed straw ash and L/S 8 for the straw, co-firing and wood ash.
由于 Cd 的浓度相对较高，生物质燃烧飞灰通常无法满足丹麦将其作为肥料回收的立法要求。在这项研究中，研究了用电渗析修复法从四种不同的生物质燃烧飞灰中去除 Cd 的潜力，目的是使这些灰分能够重新使用。这些灰分分别来自于秸秆（两种灰分）、木屑和木屑与燃油混烧的燃烧。对每种灰分进行了一系列实验室规模的电渗析修复实验。灰分中的初始 Cd 浓度在 8.8mg Cd/kg（混烧灰分）至 64mg Cd/kg（预洗秸秆灰分）之间变化，pH 值在 3.7（混烧灰分）至 13.3（木灰分）之间变化。尽管这些灰分之间存在如此大的差异，但电渗析法表现出足够的稳健性，可以处理这些灰分，因此，在用每种灰分进行的至少一次实验中，最终的 Cd 浓度都低于 2.0mg Cd/kg DM。这是在修复 2 周内实现的，对于预洗秸秆灰分的液体到固体（L/S）比例为 L/S 16，对于秸秆、混烧和木灰分的 L/S 8。
