Apr 16 2021
瑞典的研究人员开发了一种更加环保的方式，可以从水中清除重金属，染料和其他污染物。答案在于用从植物纤维素中取出的凝胶材料过滤废水，并在微波炉中产生的小碳点加[微分。
期刊上的报告可持续的婚姻和技术，KTH皇家理工学院的研究人员与Politecnico di Torino合作设计了一种更具可持续性的技术，用于生产水凝胶复合材料，这是一种用于废水去污的材料。
Minna Hakkarainen, who leads the Division of Polymer Technology at KTH Royal Institute of Technology, says that the hydrogels remove contaminants such as heavy metal ions, dyes and other common pollutants.
“地球上的总水量不会随着时间而变化，但需求确实会发生变化，”she says。"These all-lignocellulose hydrogels offer a promising, sustainable solution to help ensure access to clean water."
她说，水凝胶复合材料可以由100％的木质纤维素或植物物质制成 - 地球上最丰富的生物外壳。
One ingredient is cellulose gum (carboxymethyl cellulose, or CMC), a thickener and emulsion derived commonly from wood pulp or cotton processing byproducts and used in various food products, including ice cream. Added to the hydrogel are graphene oxide-like carbon dots synthesized from biomass with the help of microwave heat. The hydrogel composites are then cured with UV light, a mild process that takes place in water at room temperature.
水凝胶由一个不仅吸收水的聚合物链网络组成，而且还通过静电相互作用收集分子和离子 - 一种称为吸附的过程。Hakkarainen说，新过程还增强了水凝胶复合材料的稳定性，因此它们可以超过普通水凝胶，以重复进行水纯化循环。
Graphene oxide has become a favored additive to this mix, because of its high adsorption capacity, but the environmental cost of graphene oxide production is high.
"Graphene oxide is a great adsorbent, but the production process is harsh,"she says。“我们的路线基于常见的生物原材料和明显的较温和的过程，对环境的影响较小。”亚博网站下载
Graphene is derived from graphite, a crystalline form of carbon that most people would recognize as the "lead" in pencils. In oxidized form it can be used in hydrogels but the oxidation process requires harsh chemicals and conditions. Synthesizing graphene from biomass often requires temperatures of up to 1300C.
By contrast, the researchers at KTH found a way to carbonize biomass at much lower temperatures. They reduced sodium lignosulfate, a byproduct from wood pulping, into carbon flakes by heating it in water in a microwave oven. The water is brought to 240C, and it is kept at that temperature for two hours.
最终，在氧化过程之后，它们产生了大约10至80纳米直径的碳点，然后将其与甲基丙烯酸的CMC混合，并用紫外线处理以形成水凝胶。
“这是一个简单，可持续的系统，”Hakkarainen says。“它的工作原理（即使不是更好）比当前正在使用的水凝胶系统。”
来源：https://www.kth.se/en