Nanofibrous hydrogel-reduced graphene oxide membranes for effective solar-driven interfacial evaporation and desalination
Nanofibrous hydrogel-reduced graphene oxide membranes for effective solar-driven interfacial evaporation and desalination
复制标题
用于高效太阳能驱动界面蒸发与脱盐的纳米纤维水凝胶 - 还原氧化石墨烯膜
DOI：
10.1016/j.cej.2021.129998
复制
发表时间：
2021-04-29
影响因子：
15.1
通讯作者：
Mi, Baoxia
中科院分区：
文献类型：
--
作者：
Zang, Linlin;Sun, Liguo;Mi, Baoxia
吸光多孔材料的界面蒸发为利用可持续可再生太阳能进行海水淡化提供了令人兴奋的机会。然而，了解控制界面蒸发的基本机制的努力远远落后于性能研究。本文展示了一种混合纳米纤维水凝胶还原氧化石墨烯（NHrG）膜。我们通过实验表征了 NHrG 膜中水的状态，并证明了多孔膜中中间水的存在。通过监测汽化焓与膜饱和度的函数关系，我们证明了中间水的汽化在界面蒸发过程中占主导地位，从而在降低汽化焓方面发挥了关键作用。较低的焓值与其他因素（例如还原氧化石墨烯（rGO）实现的高光吸收效率和电纺水凝胶纳米纤维诱导的多孔亲水网络）一起，产生了高效的太阳能驱动界面蒸发器。 NHrG膜在一次太阳照射下的蒸发速率高达1.85 kg m-2h-1，能量转换效率高达95.4%。此外，该蒸发器在处理淡水时表现出优异的脱盐性能，实现了盐分和重金属离子的高去除率。我们的研究为性能优化和流程设计提供了重要的知识。
Interfacial evaporation from light-absorbing, porous materials have offered an exciting opportunity to utilize sustainable renewable solar energy for desalination. However, the efforts to understand the fundamental mechanisms governing the interfacial evaporation have greatly lagged behind performance studies. Herein, a hybrid nanofibrous hydrogel-reduced graphene oxide (NHrG) membrane is demonstrated in this work. We experimentally characterized the state of water in the NHrG membrane and proved the presence of intermediate water in the porous membrane. By monitoring the vaporization enthalpy as a function of membrane saturation, we demonstrated that the vaporization of intermediate water dominates the interfacial evaporation process, thus playing a key role in lowering the vaporization enthalpy. The lowered enthalpy value together with other factors, such as the high light absorption efficiency enabled by reduced graphene oxide (rGO) and the porous hydrophilic network induced by electrospun hydrogel nanofibers, led to a highly efficient solar-driven interfacial evaporator. The NHrG membrane had an evaporation rate of up to 1.85 kg m-2h-1 with a high energy conversion efficiency of 95.4% under one sun irradiation. In addition, the evaporator exhibited excellent desalination performance in treating fresh seawater and achieved high removal of salt as well as heavy metal ions. Our study provides important knowledge for performance optimization and process design.