Capture of Aldehyde VOCs Using a Series of Amine-Functionalized Cellulose Nanocrystals

Aldehydes are commonly encountered VOCs released to the atmosphere from a variety of anthropogenic sources. We have previously reported the use of poly(ethyleneimine) (PEI) modified biodegradable poly(lactic acid) nanoparticles for the capture of volatile aldehydes and carboxylic acids in the gas phase. In this study we evaluated the performance of amine-decorated cellulose materials by grafting three stable amine-bearing molecules (i. e. ethylendiamine (EDA), tris(2-aminoethyl)amine (Tris), and PEI) to the surface of cellulose micro and nanocrystals using a convenient two step protocol. The amine-modified cellulose materials were then characterized using TGA, FTIR, EDS, and elemental analysis. GC headspace experiments were conducted to assess the ability of the amine-modified cellulose materials to capture two illustrative aldehyde VOCs, hexanal and octanal, in the gas phase. PEI-cellulose nanocrystals successfully captured gaseous hexanal, and significantly outperformed related PEI-cellulose microcrystals. In a second round of optimization, cellulose nanocrystals modified with simpler amine-bearing molecules, Tris and EDA, were prepared for comparison. Tris and EDA modified cellulose nanocrystals also efficiently captured the target VOCs. These results demonstrate that the size of cellulose substrate and the chemical composition of the amine molecules on the surface are critical parameters for efficient contaminant capture.