Poly(amine) modified kaolinite clay for VOC capture.

Polyethylenimine (PEI) functionalized kaolinite clay was successfully prepared, characterized, and assessed for the remediation of volatile organic compounds (VOCs) comprising the aldehyde, carboxylic acid, and disulfide functional group classes. A gas chromatographic vapor capture assay evaluated the capability of unmodified and modified clay material to capture representative aldehyde, carboxylic acid, and disulfide VOCs in a laboratory setting. Unmodified kaolinite (Kao) clay was moderately or poorly effective at remediating these VOCs, while the poly(amine) functionalized Kao was capable of capturing VOCs in the vapor phase with reductions up to 100%. Sample cartridge tubes were packed with PEI-functionalized clay in order to assess their ability to reduce the detectable volatile fatty acid load at an open-air rendering plant in a relevant field test for applying these materials in a packed-bed scrubber application. The PEI-Kao packed cartridges were capable of significantly reducing the detectable concentration of volatile fatty acid effluent from the rendering operation. These volatile fatty acids are major contributors to nuisance odors associated with rendering.

Target-Specific Capture of Environmentally Relevant Gaseous Aldehydes and Carboxylic Acids with Functional Nanoparticles.

Aldehyde and carboxylic acid volatile organic compounds (VOCs) present significant environmental concern due to their prevalence in the atmosphere. We developed biodegradable functional nanoparticles comprised of poly(d,l-lactic acid)-poly(ethylene glycol)-poly(ethyleneimine) (PDLLA-PEG-PEI) block co-polymers that capture these VOCs by chemical reaction. Polymeric nanoparticles (NPs) preparation involved nanoprecipitation and surface functionalization with branched PEI. The PDLLA-PEG-PEI NPs were characterized by using TGA, IR, (1) H NMR, elemental analysis, and TEM. The materials feature 1°, 2°, and 3° amines on their surface, capable of capturing aldehydes and carboxylic acids from gaseous mixtures. Aldehydes were captured by a condensation reaction forming imines, whereas carboxylic acids were captured by acid/base reaction. These materials reacted selectively with target contaminants obviating off-target binding when challenged by other VOCs with orthogonal reactivity. The NPs outperformed conventional activated carbon sorbents.