Using negative emissions technologies for the net removal of greenhouse gases from the atmosphere could provide a pathway to limit global temperature rises. Direct air capture of carbon dioxide offers the prospect of permanently lowering the atmospheric CO₂ concentration, providing that economical and energy-efficient technologies can be developed and deployed on a large scale. Here, we report an approach to direct air capture, at the laboratory scale, using mostly off-the-shelf materials and equipment. First, CO₂ absorption is achieved with readily available and environmentally friendly aqueous amino acid solutions (glycine and sarcosine) using a household humidifier. The CO₂-loaded solutions are then reacted with a simple guanidine compound, which crystallizes as a very insoluble carbonate salt and regenerates the amino acid sorbent. Finally, effective CO₂ release and near-quantitative regeneration of the guanidine compound are achieved by relatively mild heating of the carbonate crystals using concentrated solar power.

使用负排放技术从大气中净去除温室气体可以提供限制全球温度上升的途径。直接空气中捕获二氧化碳提供了永久降低大气中CO ₂浓度的前景，条件是可以大规模开发和部署经济和节能的技术。在这里，我们报告了一种在实验室规模下直接使用大多数现成的材料和设备进行直接空气捕获的方法。首先，使用家用加湿器，通过容易获得且对环境友好的氨基酸水溶液（甘氨酸和肌氨酸）实现CO ₂吸收。一氧化碳₂然后将负载的溶液与简单的胍化合物反应，该胍化合物结晶为非常不溶的碳酸盐，并再生氨基酸吸附剂。最后，通过使用集中的太阳能相对温和地加热碳酸盐晶体，可以实现胍化合物的有效CO ₂释放和近乎定量的再生。