Department of Earth and Environmental Sciences, Università di Milano Bicocca, Piazza Della Scienza 1, 20126, Milano, Italy.
RAFFMETAL s.p.a., Via Malpaga 82, 25070, Casto, BS, Italy.
Chemosphere. 2017 Aug;181:409-417. doi: 10.1016/j.chemosphere.2017.04.097. Epub 2017 Apr 23.
A 13-years study shows that a careful design of the flue gas cleaning system of a full scale secondary aluminium refining plant results in a minimized and very stable emission of Polychlorinated Dibenzo-p-Dioxins (PCDD), Polychlorinated Dibenzo Furans (PCDF) and dioxin-like Polychlorinated Biphenyls (PCB). The value of equivalent toxicity of PCDD/F in the emission was definitely of an order of magnitude less than the regulation limit. In the initial flue gas cleaning system, the PCB mean fingerprint after the slow cooling of the flue gas was typical of de novo synthesis. Instead, in the presence of quenching, there was evidence that the fast cooling of flue gas prevented the PCB de novo synthesis. In fact, the PCB profile was similar to that in the air collected from the aspiration hoods for the quenching. The gas-phase and solid-phase partitioning of PCBs, before and after the fabric filters, highlights the predominant role of the vapor phase with respect to the total removal efficiency. The polycyclic aromatic hydrocarbons breakdown could be an additional de novo formation pathway even in industrial plants.
一项为期 13 年的研究表明，精心设计的全规模二次铝精炼厂烟气净化系统可实现最小化且非常稳定的多氯二苯并对二恶英（PCDD）、多氯二苯并呋喃（PCDF）和类似二恶英的多氯联苯（PCB）排放。排放物中 PCDD/F 的等效毒性值明显低于规定限值。在初始烟气净化系统中，在烟气缓慢冷却后，PCB 的平均指纹特征典型地属于从头合成。相反，在存在淬火的情况下，有证据表明，烟气的快速冷却阻止了 PCB 的从头合成。事实上，PCB 谱与在用于淬火的吸气罩中收集到的空气中的 PCB 谱相似。在织物过滤器前后，PCBs 的气-固分配突出了气相相对于总去除效率的主要作用。多环芳烃的分解可能是工业工厂中甚至是另外一条新的形成途径。
