Experimental evaluation of VOC removal efficiency of a coconut shell activated carbon filter for indoor air quality enhancement

Abstract

The present study evaluated the performance of a commercially available activated carbon filter for VOC removal from air through the analysis of real samples. The filter was tested for VOC reduction efficiencies in a PVC portable inflatable bubble provided with an air purifier system called Airbox II Phase by Zonair3d, as described hereinafter. The filter was placed in the Airbox II Phase of the bubble, between a pre-filter and a particulate HEPA H14 filter. Simultaneous duplicate samples were taken from the input air duct before the driving system and from the bubble. VOC were dynamically sampled during 2-h control periods by connecting custom packed glass multi-sorbent cartridge tubes (Carbotrap, Carbopack X and Carboxen 569) to air pump samplers. A validated analytical method based on TD-GC/MS was used to quantify a wide variety of VOC families (alkanes, aromatic hydrocarbons, alcohols, ketones, halocarbons, aldehydes, esters, terpenes, ethers, glycols and nitrogenated compounds). VOC family removal efficiencies ranged from 51 ± 19% to 78 ± 22% with input indoor air, and from 42 ± 16% to 91 ± 18% with input outdoor air. No significant differences in reduction efficiencies (t-test; p < 0.05) were observed between using indoor or outdoor air. Several aldehydes were desorbed from the filter at low concentrations (0.09–21.19 μg m−3) when outdoor air was used as input air. Ozone removal efficiency was assessed by a continuous monitoring system. A 100% yield was obtained in all cases where ozone was present.