East Central University, College of Health and Sciences, Ada, OK 74820, United States.
Chemosphere. 2012 Nov;89(10):1218-23. doi: 10.1016/j.chemosphere.2012.07.040. Epub 2012 Aug 22.
Chemical oxidation regeneration of granular activated carbon (GAC) is a developing technology that can be carried out utilizing thermally-activated persulfate. During chemical regeneration of GAC, aggressive oxidative conditions lead to high acidity (pH<2) and the accumulation of sodium persulfate residuals in the GAC. In this study, we investigated the impact of chemical oxidation on the sorption characteristics of methyl-tert butyl ether (MTBE) in GAC. Loss of MTBE sorption was measured in thermally-activated persulfate regenerated GAC. The accumulation of sulfur was partially responsible for the blockage of sorption sites, but sorption loss was amplified under oxidizing and acidic conditions and attributed to the formation of acidic surface oxides and enhanced electrostatic attraction and accumulation of SO(4)(2-) in GAC. Raising the pH in the GAC slurry resulted in the removal of the residual sulfate and improved MTBE sorption indicating that the mechanisms responsible for MTBE sorption loss were reversible. These results establish baseline conditions and parameters that can be used to optimize pilot- and full-scale deployment of thermally-activated persulfate regeneration of GAC.
颗粒状活性炭（GAC）的化学氧化再生是一项正在发展中的技术，可以利用热活化过硫酸盐来进行。在 GAC 的化学再生过程中，剧烈的氧化条件会导致高酸度（pH<2）和 GAC 中过硫酸钠残留物的积累。在本研究中，我们研究了化学氧化对 GAC 中甲基叔丁基醚（MTBE）吸附特性的影响。在热活化过硫酸盐再生的 GAC 中测量了 MTBE 吸附的损失。硫的积累部分导致了吸附位点的堵塞，但在氧化和酸性条件下，吸附损失加剧，这归因于酸性表面氧化物的形成以及增强的静电吸引和 GAC 中 SO(4)(2-)的积累。提高 GAC 浆液中的 pH 值会导致残余硫酸盐的去除，并改善 MTBE 的吸附，这表明导致 MTBE 吸附损失的机制是可逆的。这些结果确立了基准条件和参数，可用于优化热活化过硫酸盐再生 GAC 的中试和全规模部署。
