Eco-friendly hierarchical porous palygorskite/wood fiber aerogels with smart indoor humidity control

Abstract

Advocating low-carbon has become the consensus of all countries in the world and a necessary means of sustainable development. Humidity-control materials (HCMs) can smartly regulate indoor air humidity without energy consumption, thereby greatly reducing building energy consumption. However, the preparation process of traditional HCMs involved toxic or corrosive substances, which was not eco-friendly. In this work, monolithic humidity-control palygorskite/wood fiber composite aerogel materials (PalOH/WF-HCAMs) with hierarchical porous were prepared by freeze-drying method. The composite aerogels had low densities (<0.1 g/cm3), good mechanical properties (Young's modulus up to 11 MPa), and excellent self-adjusting humidity ability with a water vapor content of up to 364 g/m2 (24 h, RH = 95%) without adding any inorganic salt. Actual evaluation tests proved that PalOH/WF-HCAM could spontaneously rapidly maintain indoor ambient humidity at 50%–65% without additional energy supply, and the humidity-control performance was still stable after 30 cycles (RH = 20–90%). It is particularly important that the synthesis process of PalOH/WF-HCAMs is economical and eco-friendly without adding any toxic organic solvent. These results demonstrate that eco-friendly, hierarchical porous PalOH/WF-HCAMs are excllent candidates in indoor humidity-control application.