NSF CONACyT-GOALI: Arsenic Removal from Water with Iron-Tailored Activated Carbon: Fundamental Redox Characterization

[05:23 . 196] Dempsey本项目旨在评估用柠檬酸铁预处理的颗粒活性炭（GAC）具有很高的砷（As）去除能力的机理。pi先前的研究发现了这种高容量现象，这不能用传统的平衡模型来解释，这种模型涉及氢氧化铁或铁砷沉淀的吸附。该研究将验证一个假设，即As:Fe摩尔比大于1:1时As(V)的去除是由于GAC孔隙中硫化物的还原和随后的沉淀。这些项目还将调查各种基本水质/化学特性的重要性，如pH值、碱度、天然有机物和溶解氧的浓度，对砷去除的速度和程度的影响。采用扩展x射线吸收精细结构光谱（EXAFS）和穆斯堡尔光谱（Mossbauer spectroscopy）测定砷经定制GAC去除后的形态。

0523196 Dempsey This project seeks to evaluate the mechanisms for very high removal capacities of arsenic (As) by granular activated carbon (GAC) that has been pretreated with iron-citrate. Previous studies by the PIs found this phenomenon of high capacity, which cannot be explained by conventional equilibrium models involving sorption onto ferric hydroxide or iron-arsenic precipitates. The study will test the hypothesis that removal of As(V) at a greater than 1:1 molar ratio of As:Fe is due to reduction and subsequent precipitation of arsenic sulfides within the pores of GAC. The PIs also will investigate the importance of various basic water quality/chemistry characteristics, such as pH, alkalinity, and concentrations of natural organic matter and dissolved oxygen, on rates and extent of As removal. The speciation of As after its removal by tailored GAC will be determined using extended x-ray absorption fine-structure spectroscopy (EXAFS) and Mossbauer spectroscopy.