# Silk-Nano-Fibroin Aerogels: A Bio-Derived, Amine-Rich Platform for Rapid and Reversible CO2 Capture

## TL;DR

Silk-based aerogels offer a sustainable, low-cost, and efficient way to capture and release CO2 quickly and under mild conditions.

## Contribution

Silk-nanofibroin aerogels are introduced as a novel, amine-rich, bio-derived platform for rapid and reversible CO2 capture.

## Key findings

- Silk-nanofibroin aerogels show CO2 adsorption capacity comparable to advanced solid sorbents.
- They can be regenerated at low temperatures (60°C) and maintain stability under humid conditions.
- Spectroscopic analyses confirm reversible CO2 chemisorption via surface amine sites.

## Abstract

Despite growing interest in biobased materials, rapid,
low-temperature
CO2 capture using amine-rich natural sorbents has received
limited attention. Various porous solid sorbents have drawn significant
research interest as promising carbon capture materials. However,
high synthesis cost, limited CO2 adsorption capacity, sluggish
adsorption–desorption kinetics, high sorbent regeneration temperature,
and poor operational stability remain major challenges for their practical
implementation. Here, we present silk-nanofibroin aerogels derived
from natural mulberry silk as a sustainable, amine-rich, and porous
solid-support-free sorbent platform for energy-efficient CO2 capture. The aerogels exhibit a CO2 adsorption capacity
competitive with state-of-the-art amino acid and amino acid ionic
liquid-based solid sorbents. Thermogravimetric analysis confirms high
thermal stability up to ∼250 °Csubstantially higher
than that of conventional amine sorbentswhile complete sorbent
regeneration occurs at only 60 °C. Furthermore, the silk-nanofibroin
aerogels demonstrate rapid adsorption–desorption kinetics,
excellent multicycle stability, and full retention of CO2 adsorption capacity under humid conditions. Spectroscopic analyses
(XPS, FTIR, Raman, and solid-state 13C NMR) confirm reversible
CO2 chemisorption through intrinsic amine sites at the
silk-fibroin surface. Overall, this work establishes silk-nanofibroin
aerogels as a sustainable and low-cost route toward energy-efficient
CO2 capture.