ABSTRACT

TiO₂-PILCs and iron-doped TiO₂-PILCs were employed in order to destroy toxic microcystin-LR in the presence of H₂O₂ under the UV light. While less than 5% of the initial microcystin-LR and TOC disappeared in 240 min with the TiO₂-PILCs, almost complete conversion of microcystin-LR could be achieved in 180 min on the 10 wt% iron-doped TiO₂-PILC-A. On the exterior surface of the iron-doped TiO₂-PILCs were mainly located iron particles which had nano-sized diameter and Fe²⁺/Fe³⁺ cations together. Through Fenton-type oxidation on iron particles with H₂O₂, the big microcystin-LR molecules were converted primarily into smaller intermediate organic molecules of hydrocarbons, carboxylic acids and organic amines. The smaller intermediate molecules were believed to be diffused into the pores of the iron-doped TiO₂-PILCs and to be further mineralized into CO₂ and H₂O through the action of photocatalysis on the TiO₂ pillars. However, complete conversion of TOC could not be obtained due to the iron particle deactivation. XPS, TPO and TEM studies showed the continuous accumulation of carbonaceous materials onto the surface of iron particles.

摘要

TiO ₂ -PILCs 和铁掺杂的TiO ₂ -PILCs 被用来在紫外光下在H ₂ O ₂存在下破坏有毒的微囊藻毒素-LR 。虽然使用 TiO ₂ -PILCs在 240 分钟内不到 5% 的初始微囊藻毒素-LR 和 TOC 消失，但在 10 wt% 铁掺杂的 TiO ₂ -PILC-上，微囊藻毒素-LR 几乎可以在 180 分钟内完全转化一种。在铁掺杂的TiO ₂ -PILCs的外表面上主要分布有纳米尺寸的铁颗粒和Fe ²⁺ /Fe ³⁺阳离子。通过 H ₂ O ₂对铁颗粒进行 Fenton 型氧化，大的微囊藻毒素-LR 分子主要转化为较小的中间有机分子，如碳氢化合物、羧酸和有机胺。较小的中间分子被认为扩散到铁掺杂的 TiO ₂ -PILCs的孔中，并通过光催化作用在 TiO ₂柱上进一步矿化成 CO ₂和 H ₂ O。然而，由于铁颗粒失活，无法获得 TOC 的完全转化。XPS、TPO 和 TEM 研究表明含碳材料在铁颗粒表面连续积累。