布法罗大学（UB）研究人员开发了一种新型的3D印刷水石墨烯气凝胶，可以在大型废水处理厂中缩放以供使用。
该新型材料由类似泡沫塑料的气凝胶，格子石墨烯和两种生物启发的聚合物组成，能够从饮用水中清除染料，金属和有机溶剂，并具有100％效率。与类似的纳米片不同，科学家的设计是可重复使用的，不会留下残留物，并且可以将3D印刷成更大的尺寸，因此现在他们旨在将其商业化用于工业规模的部署。
“The goal is to safely remove contaminants from water without releasing any problematic chemical residue,” explained study co-author and assistant professor of environmental engineering at UB, Nirupam Aich. “The aerogels we’ve created hold their structure when put into water treatment systems, and they can be applied in diverse water treatment applications.”
石墨烯的净化潜力
石墨烯纳米材料具有较高的比表面积和能够同时发挥静电和疏水相互作用的能力，最近出现了作为吸收水污染物的一种有希望的方法。特别是，该材料的氧化石墨烯（GO）衍生物已进行了广泛的测试，以进行净水目的，但事实证明，从工业过程中恢复的GO设备很难。
Recently, scientists have experimented with assembling nanosheets into macroscopic aerogels, lending them a higher absorption capacity and making them more retrievable. However, such graphene aerogels are rarely deployed within treatment facilities due to processing restrictions, that prevent them from being incorporated into industrial purifying reactors, columns and filters.
By contrast, Direct Ink Writing (DIW) offers users precise control over the size, shape and architecture of parts produced, while the process’ repeatability makes it highly scalable. Already, 3D printing has been deployed to create thermal, energy and biomedical graphene devices, hence the Buffalo scientists surmised that it could be used to develop a mass-manufactured water purifying system as well.
可伸缩的水盘气凝胶
In order to produce aerogels quickly and consistently, the researchers first needed to create a graphene-based ink, with the properties to allow water absorption while preventing particle agglomeration. To achieve this, the Buffalo team added the bio-inspired polydopamine (PDA) and bovine serum albumin (BSA) to a GO powder, yielding a novel viscoelasticity-optimized 3D printing material.
利用翻新Ultimaker2 GO 3D printer, the researchers then fabricated a 12 mm (D) x 4 mm (H) cylindrical test sample, before freezing and freeze-drying it, leaving a G-PDA-BSA aerogel. During subsequent testing, the team repeatedly exposed their material to organic solvent loaded-water, as a means of assessing its contaminant removal capacity.
On each occasion, the graphene aerogel was able to remove 100% of the solvents, while reducing colored dye contamination by up to 20%. In later design iterations, the scientists even managed to reconfigure their aerogel, so that it could root-out heavy metals like lead and chromium, alloys that remain difficult to remove at current water decontamination facilities.
随着进一步的发展，科学家认为，他们的可扩展方法也可以应用于创建其他功能性可重复使用的纳米材料，并以吸附剂，反应堆或过滤器等设备的形式在水过滤厂中使用潜在的最终用途应用。
Aich总结道：“我们可以使用这些气凝胶不仅包含石墨烯颗粒，而且还可以用作催化剂的纳米颗粒。”“未来的目标是将纳米颗粒嵌入到这些气凝胶的墙壁和表面中，并且它们不仅能够降解或破坏生物污染物，还可以降解或破坏化学污染物。”
3D printed purification devices
鉴于3D打印允许使用的低成本和设计灵活性，它越来越多地用于创建新颖的设备，使饮用水更容易为有需要的人使用。就在去年，University of Cambridge旋转蓝色水龙头received英国创新为其资金3D printed chlorine doser，可以将其安装在发展中国家的水系统上，以使其安全饮用。
Similarly, researchers at theUniversity of Bathhave developed a3D打印的水净化“平板”，这利用太阳的热量和紫外线来杀死生活在液体中的有害微生物。该技术旨在为不太富裕的亚洲，非洲和拉丁美洲社区提供干净的饮用水。
在更军事上，GE Research最近被授予1430万美元国防高级研究计划局(DARPA) to 3D print a device that用薄空产生水。便携式系统是为了为最多150名士兵提供水，后来可以部署以解决世界各地的水短缺。
The researchers’ findings are detailed in their paper titled “Emerging investigator series: 3D printed graphene-biopolymer aerogels for water contaminant removal: a proof of concept。”这项研究由Arvid Masud，Chi Zhoub和Nirupam Aich共同撰写。
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特色图片显示了科学家在Kim擦拭处的冻干超轻的G-PDA-BSA气凝胶。通过布法罗大学的照片。
