Department of Civil and Enviornmental Engineering, The Pennsylvania State University, University Park, PA 16802, USA.
Water Sci Technol. 2010;61(2):441-53. doi: 10.2166/wst.2010.826.
The authors have combined corrosion of steel fittings or perforated sheets with granular activated carbon (GAC) that had been pre-treated with Fe(III)-citrate, to produce an innovative and low-maintenance technique for removing arsenic from groundwater. Removal of arsenic was measured using two GAC column configurations: rapid small scale column tests (RSSCT's) and mini-column tests. Independent variables included pH, pre-corrosion procedure, and idling of the column (i.e. intentionally stopping flow for defined times in order to create reducing conditions). Use of corroded steel plus pre-treated GAC removed arsenic to below 10 microg/L for up to 248,000 bed volumes (BV) at pH 6, compared to 7,000 BVs for pre-treated GAC without pre-corroded steel. Performance was not as good at pH 6.5 or 7.5. Idling the system recovered the iron corrosion ability by reducing the passive Fe(III) layer on pre-corroded steel surface, as a result the BVs to arsenic breakthrough was doubled. But idling also caused brief periods of arsenic and iron release after restart, due to reductive dissolution of arsenic-containing ferric oxides. GAC was also effective as filtration media for removal of iron (hydr)oxide particles (and associated arsenic) that was released from the pre-corroded iron.
作者将经过预处理的三价铁-柠檬酸处理过的钢配件或穿孔板的腐蚀与颗粒状活性炭 (GAC) 结合在一起，开发出了一种创新且维护成本低的地下水除砷技术。采用两种 GAC 柱配置来测量砷的去除效果：快速小柱试验（RSSCT）和迷你柱试验。自变量包括 pH 值、预腐蚀程序以及柱的闲置（即故意停止流动一段时间，以创造还原条件）。使用腐蚀钢和预处理过的 GAC，在 pH 值为 6 时，可将砷去除到 10 微克/升以下，处理量高达 248000 床体积（BV），而未经预腐蚀钢预处理的 GAC 仅需 7000 BV。在 pH 值为 6.5 或 7.5 时，效果不如 pH 值为 6 时好。系统闲置通过减少预腐蚀钢表面上的钝化三价铁层，恢复了铁的腐蚀能力，因此砷穿透的 BV 增加了一倍。但闲置也会导致重新启动后出现短暂的砷和铁释放期，这是由于含砷的铁氧化物的还原溶解所致。GAC 还可作为过滤介质，有效去除从预腐蚀铁中释放的铁（氢）氧化物颗粒（和相关的砷）。
