Department of Mechanical Engineering, University of California, Berkeley, California, USA.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2010 Sep;45(11):1446-60. doi: 10.1080/10934529.2010.500940.
We describe laboratory and field results of a novel arsenic removal adsorbent called 'Arsenic Removal Using Bottom Ash' (ARUBA). ARUBA is prepared by coating particles of coal bottom ash, a waste material from coal fired power plants, with iron (hydr)oxide. The coating process is simple and conducted at room temperature and atmospheric pressure. Material costs for ARUBA are estimated to be low (approximately $0.08 per kg) and arsenic remediation with ARUBA has the potential to be affordable to resource-constrained communities. ARUBA is used for removing arsenic via a dispersal-and-removal process, and we envision that ARUBA would be used in community-scale water treatment centers. We show that ARUBA is able to reduce arsenic concentrations in contaminated Bangladesh groundwater to below the Bangladesh standard of 50 ppb. Using the Langmuir isotherm (R(2) = 0.77) ARUBA's adsorption capacity in treating real groundwater is 2.6 x 10(- 6)mol/g (0.20 mg/g). Time-to-90% (defined as the time interval for ARUBA to remove 90% of the total amount of arsenic that is removed at equilibrium) is less than 1 hour. Reaction rates (pseudo-second-order kinetic model, R(2) > or = 0.99) increase from 2.4 x 10(5) to 7.2 x 10(5) g mol(- 1)min(- 1) as the groundwater arsenic concentration decreases from 560 to 170 ppb. We show that ARUBA's arsenic adsorption density (AAD), defined as the milligrams of arsenic removed at equilibrium per gram of ARUBA added, is linearly dependent on the initial arsenic concentration of the groundwater sample, for initial arsenic concentrations of up to 1600 ppb and an ARUBA dose of 4.0 g/L. This makes it easy to determine the amount of ARUBA required to treat a groundwater source when its arsenic concentration is known and less than 1600 ppb. Storing contaminated groundwater for two to three days before treatment is seen to significantly increase ARUBA's AAD. ARUBA can be separated from treated water by coagulation and clarification, which is expected to be less expensive than filtration of micron-scale particles, further contributing to the affordability of a community-scale water treatment center.
我们描述了一种新型砷去除吸附剂的实验室和现场结果，称为“利用炉底渣去除砷（ARUBA）”。ARUBA 通过用铁（氢）氧化物涂覆来自燃煤电厂的废物煤底渣颗粒来制备。该涂覆过程简单，在室温常压下进行。预计 ARUBA 的材料成本低（约每公斤 0.08 美元），并且使用 ARUBA 进行砷修复对于资源有限的社区来说具有成本效益。ARUBA 通过分散和去除过程用于去除砷，我们设想 ARUBA 将用于社区规模的水处理中心。我们表明，ARUBA 能够将受污染的孟加拉国地下水的砷浓度降低到孟加拉国标准的 50ppb 以下。使用 Langmuir 等温线（R²=0.77），ARUBA 处理实际地下水的吸附能力为 2.6×10⁻⁶mol/g（0.20mg/g）。达到 90%的时间（定义为 ARUBA 去除平衡时去除的总砷量的 90%所需的时间间隔）不到 1 小时。反应速率（准二级动力学模型，R²≥0.99）随着地下水砷浓度从 560 到 170ppb 的降低而从 2.4×10⁵增加到 7.2×10⁵g mol⁻¹min⁻¹。我们表明，ARUBA 的砷吸附密度（AAD）定义为每克添加的 ARUBA 去除的砷毫克数，与地下水样品的初始砷浓度呈线性相关，对于初始砷浓度高达 1600ppb 和 4.0g/L 的 ARUBA 剂量。这使得在知道地下水的砷浓度并且小于 1600ppb 时，很容易确定处理地下水源所需的 ARUBA 量。在处理之前将受污染的地下水储存两到三天被发现可以显著提高 ARUBA 的 AAD。ARUBA 可以通过混凝和澄清与处理后的水分离，预计比过滤微米级颗粒便宜，这进一步有助于社区规模水处理中心的成本效益。
