Metke Thomas, Westover Andrew S, Carter Rachel, Oakes Landon, Douglas Anna, Pint Cary L
Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37235, USA.
Interdisciplinary Materials Science Program, Vanderbilt University, Nashville, TN 37235, USA.
Sci Rep. 2016 Apr 22;6:24680. doi: 10.1038/srep24680.
Energy efficient water desalination processes employing low-cost and earth-abundant materials is a critical step to sustainably manage future human needs for clean water resources. Here we demonstrate that porous silicon - a material harnessing earth abundance, cost, and environmental/biological compatibility is a candidate material for water desalination. With appropriate surface passivation of the porous silicon material to prevent surface corrosion in aqueous environments, we show that porous silicon templates can enable salt removal in capacitive deionization (CDI) ranging from 0.36% by mass at the onset from fresh to brackish water (10 mM, or 0.06% salinity) to 0.52% in ocean water salt concentrations (500 mM, or ~0.3% salinity). This is on par with reports of most carbon nanomaterial based CDI systems based on particulate electrodes and covers the full salinity range required of a CDI system with a total ocean-to-fresh water required energy input of ~1.45 Wh/L. The use of porous silicon for CDI enables new routes to directly couple water desalination technology with microfluidic systems and photovoltaics that natively use silicon materials, while mitigating adverse effects of water contamination occurring from nanoparticulate-based CDI electrodes.
采用低成本且储量丰富的材料实现节能海水淡化工艺是可持续满足未来人类对清洁水资源需求的关键一步。在此，我们证明了多孔硅——一种兼具储量丰富、成本低廉以及环境/生物兼容性的材料——是海水淡化的候选材料。通过对多孔硅材料进行适当的表面钝化处理以防止其在水环境中发生表面腐蚀，我们发现多孔硅模板能够在电容去离子化（CDI）过程中实现盐分去除，去除率从初始处理淡水至微咸水（10 mM，即0.06%盐度）时的0.36%质量分数，到海水盐浓度（500 mM，即约0.3%盐度）时的0.52%质量分数。这与大多数基于颗粒电极的碳纳米材料CDI系统的报道相当，并且涵盖了CDI系统所需的全盐度范围，从海水到淡水的总能量输入约为1.45 Wh/L。将多孔硅用于CDI能够开辟新途径，使海水淡化技术直接与微流体系统以及天然使用硅材料的光伏系统相结合，同时减轻基于纳米颗粒的CDI电极所产生的水污染负面影响。
