Surface modified highly porous egg-shell membrane derived granular activated carbon coated on paper substrate and its humidity sensing properties

• DOI: 10.1016/j.matchemphys.2021.125486
• Publication Date: 2021-11-24T17:19:16Z
• Authors: Deepa Kathiravan; Bohr-Ran Huang; Adhimoorthy Sarav...
• Keywords: 13. Climate action; 02 engineering and technology; 0210 nano-technology; 7. Clean energy

Abstract Herein, we report a highly porous granular activated carbon (AC) from the biowaste of hen egg-shell membrane (HEM) for the detection of relative humidity (RH) using cellulose paper as substrate. As a novel strategy, the present AC is prepared through solvent-free thermal activation at high temperature in N2 atmosphere. No other chemical or surfactants were used for activation. The present AC derived from HEM exhibits both microporous and mesoporous structure with good sorption properties as exposed by TEM and BET studies. Accordingly, the adsorptivity of present AC is envisioned to act as an effective humidity sensor. The sensor response to RH varied from 10 to 85% shows the rapid response and recovery times (4/14 s). The high water uptake of highly porous HEM derived AC with Nafion improves the ionic conductivity (through protonation) at low to high humid air. Furthermore, the present sensor enables to detect the modulation of moisture air from user's speech and breath from the perspective of real-time monitoring. The salient features of this eco-friendly sensor is its high sensitivity, reliability, and rapid response that makes it a promising candidate for flexible sensor devices.