Arienzo M, Chiarenzelli J, Scrudato R, Pagano J, Falanga L, Connor B
Dipartimento di Scienze Chimico-Agrarie, Università degli Studi di Napoli Federico II, Italy.
Chemosphere. 2001 Sep;44(6):1339-46. doi: 10.1016/s0045-6535(00)00361-1.
A study was conducted to explore some of the basic processes of polychlorinated biphenyl (PCB) destruction by a new technology termed electrochemical peroxidation process (ECP). ECP represents an enhancement of the classic Fenton reaction (H2O2 + Fe2+) in which iron is electrochemically generated by steel electrodes. Focus was on the extent of adsorption of a mixture of Aroclor 1248 on steel electrodes in comparison to iron filings. Commercially available zero-valent iron filings rapidly adsorbed PCBs from an aqueous solution of Aroclor 1248. Within 4 h, all the PCBs were adsorbed at 1%, 5%, and 10% Fe0 (w/v) concentrations. Little difference in adsorption was found between acidic (2.3) and unamended solutions (pH 5.5), even though significant differences in iron oxidation state and Fe2+ concentrations were measured in solution. PCB adsorption also occurs on steel electrodes regardless of the pH or electric current applied (AC or DC), suggesting the combination of oxidizing (free radical-mediated reactions) and reducing (dechlorination reactions) iron-mediated degradation pathways may be possible. Extraction of the iron powder after 48 h of contact time yielded the progressive recovery of biphenyl with increasing Fe mass(from 0.4% to 3.5%) and changes of the PCB congener-specific pattern as a consequence of dechlorination. A variety of daughter congeners similar to those accumulated during anaerobic microbial dechlorination of Aroclor 1248 in contaminated sediments indicate preferential removal of meta- and para-chlorines.
开展了一项研究，以探索一种名为电化学过氧化过程（ECP）的新技术对多氯联苯（PCB）的一些基本破坏过程。ECP是对经典芬顿反应（H2O2 + Fe2+）的改进，其中铁由钢电极电化学产生。重点是与铁屑相比，Aroclor 1248混合物在钢电极上的吸附程度。市售的零价铁屑能迅速从Aroclor 1248水溶液中吸附多氯联苯。在4小时内，所有多氯联苯在1%、5%和10% Fe0（w/v）浓度下均被吸附。尽管在溶液中测得铁的氧化态和Fe2+浓度存在显著差异，但在酸性（2.3）溶液和未调节溶液（pH 5.5）之间未发现吸附有明显差异。无论施加的pH值或电流（交流或直流）如何，多氯联苯在钢电极上也会发生吸附，这表明氧化（自由基介导反应）和还原（脱氯反应）的铁介导降解途径可能同时存在。接触48小时后对铁粉进行萃取，随着铁质量的增加（从0.4%到3.5%），联苯逐渐回收，并且由于脱氯作用，多氯联苯同系物的特定模式发生了变化。与受污染沉积物中Aroclor 1248厌氧微生物脱氯过程中积累的那些类似的各种子同系物，表明间位和对位氯优先被去除。
