Environ Technol. 2014 Mar-Apr;35(5-8):973-83. doi: 10.1080/09593330.2013.857700.
This study provides mechanistic insights into the passivation of the packing particles during the treatment of acrylonitrile-butadiene-styrene (ABS) resin wastewater by the Fe0/GAC system. The granular-activated carbon (GAC) and iron chippings (Fe0) were mixed together with a volumetric ratio of 1:1. GAC has a mean particle size of approximately 3-5 mm, a specific surface of 748 m2 g(-1), a total pore volume of 0.48 mL g(-1) and a bulk density of 0.49 g cm(-3). The iron chippings have a compact and non-porous surface morphology. The results show that the packing particles in the Fe0/GAC system would lose their activity because the removal of TOC and PO4(3-) for ABS resin wastewater could not carried out by the Fe0/GAC system after 40 days continuous running. Meanwhile, the availability of O2 and intrinsic reactivity of Fe0 play a key role on the form of passive film with different iron oxidation states. The passive film on the surface of iron chippings was formed by two phases: (a) local corrosion phase (0-20 d) and (b) co-precipitation phase (20-40 d), while that of GAC was mainly formed by the co-precipitation of corrosion products with SO4(2-) and PO4(3-) because SO4(2-) and PO4(3-) would not easily reach the Fe0 surface. Therefore, in order to avoid the occurrence of filler passivation, high concentrations of SO4(2-) and PO4(3-) in wastewater should be removed before the treatment process of the Fe/GAC system.
本研究为 Fe0/GAC 系统处理丙烯腈-丁二烯-苯乙烯（ABS）树脂废水中的颗粒状活性炭（GAC）的钝化机制提供了深入的了解。将 GAC 和铁屑（Fe0）以 1:1 的体积比混合。GAC 的平均粒径约为 3-5mm，比表面积为 748m2g(-1)，总孔体积为 0.48m L g(-1)，堆积密度为 0.49gcm(-3)。铁屑具有致密且无孔的表面形态。结果表明，由于在连续运行 40 天后，Fe0/GAC 系统无法去除 ABS 树脂废水中的 TOC 和 PO4(3-)，因此系统中的填充颗粒会失去活性。同时，O2 的可用性和 Fe0 的固有反应性对具有不同铁氧化态的钝化膜的形成起着关键作用。铁屑表面的钝化膜由两个阶段形成：（a）局部腐蚀阶段（0-20d）和（b）共沉淀阶段（20-40d），而 GAC 主要是由腐蚀产物与 SO4(2-)和 PO4(3-)的共沉淀形成的，因为 SO4(2-)和 PO4(3-)不易到达 Fe0 表面。因此，为了避免填充剂钝化的发生，在处理 Fe/GAC 系统之前，应去除废水中高浓度的 SO4(2-)和 PO4(3-)。
