Scaled Synthesis of Polyamine-Modified Cellulose Nanocrystals from Bulk Cotton and Their Use for Capturing Volatile Organic Compounds

Abstract

We have previously demonstrated that cellulose nanocrystals modified with poly(ethylenimine) (PEI-f-CNC) are capable of capturing volatile organic compounds (VOCs) associated with malodors. In this manuscript, we describe our efforts to develop a scalable synthesis of these materials from bulk cotton. This work culminated in a reliable protocol for the synthesis of unmodified cellulose nanocrystals (CNCs) from bulk cotton on a 0.5 kg scale. Additionally, we developed a protocol for the modification of the CNCs by means of sequential 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) oxidation and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) coupling to modify their surface with poly(ethylenimine) on a 100 g scale. Subsequently, we evaluated the performance of the PEI-f-CNC materials that were prepared in a series of VOC capture experiments. First, we demonstrated their efficacy in capturing volatile fatty acids emitted at a rendering plant when formulated as packed-bed filter cartridges. Secondly, we evaluated the potential to use aqueous PEI-f-CNC suspensions as a spray-based delivery method for VOC remediation. In both cases, the PEI-f-CNC formulations reduced detectable malodor VOCs by greater than 90%. The facile scaled synthesis of these materials and their excellent performance at VOC remediation suggest that they may emerge as a useful strategy for the remediation of VOCs associated with odor.

Removal of metals and inorganics from rendered fat using polyamine-modified cellulose nanocrystals

“…Specic details regarding the preparation of the CNC and CNC-PEI can be found elsewhere. 37,38 The experimental procedure involved the oxidation of cellulose nanocrystals (CNC) using TEMPO-mediated oxidation. The CNC suspension was combined with TEMPO and sodium bromide, and then sodium hypochlorite was added to initiate the oxidation reaction.…”

“…To this end, two CNC materials were tested and compared: unmodied CNC (featuring -OH functional groups) and poly(ethylenimine)-modied CNC (PEI-CNC, featuring -NH 2 functional groups on the surface). 37,38 The latter is especially important considering that the addition of the polyethyleneimine groups can enhance the adsorptive characteristics of these materials. 42 The resulting primary and secondary amino groups would have the ability to be electron donors, allowing the formation of a coordination complex with the metal ions in the sample.…”