Construction of CO<sub>2</sub> Absorption Protein Hydrogels Using MgO Nanoparticles as Cross-Linkers
Hao Zhang, Tuo Zhang, Jiachen Zang, Chenyan Lv, Guanghua Zhao
Abstract
CO 2 mineralization by colloidal nanoclusters of MgO under mild conditions to reduce its levels in the atmosphere remains challenged. On the other hand, protein hydrogels are generally limited for a broader usage basin due to their poor mechanical properties. Inspired by biomineralization in nature, herein, we fabricated a new type of hybrid hydrogel consisting of β-lactoglobulin (βLG) amyloid fibrils and MgO nanoparticles as solid cross-linking agents. Interestingly, except for their self-recovery property and high thermal stability, the fabricated hybrid hydrogels showed two orders of magnitude improved strength compared to known divalent ion-induced amyloid fibril gels. Notably, the MgO nanoparticles endow the hybrid gels with the ability of absorption CO 2 and convert it into hydromagnesite. Quantitatively, per gram of the hybrid hydrogels formed by βLG cross-linked with 40 mM MgO nanoparticles can absorb 2.8 mmol of CO 2 . Consequently, the yield stress of the obtained CO 2 mineralization hydrogels was markedly improved by the formed hydromagnesite as fillers. This proof-of-concept study demonstrates that the fabricated MgO-βLG hydrogels could serve as a CO 2 absorbent for practical applications.