A coupled technique to eliminate overall nonpolar and polar volatile organic compounds from paint production industry

Abstract

Volatile organic compounds (VOCs) emitted from their manufacturing have a high recycling value but contribute negatively to the environment. Paints as a significant source of VOCs could largely contribute to their emissions. This study employed a pilot scale system for recovery and elimination of highly concentrated VOCs (up to 1.1 × 106 μg m−3) from a paint packaging workshop, which uses the integrated adsorption-cryogenic condensation with photocatalytic oxidation (PCO). Over a 60-day continuous treatment period, average recovery efficiencies of 96.1%, 100%, 97.1% and 98.6% were achieved for aromatic hydrocarbons (AHs), aliphatic hydrocarbons (AlHs), halogenated hydrocarbons (HHs) and oxygenated VOCs (OVOCs), respectively. Data analysis and theoretical calculations confirmed that nonpolar VOCs were preferentially adsorbed, enriched and recycled by activated carbon adsorption (AHs, AlHs and OVOCs > HHs), while residual polar VOCs were subject to subsequent PCO decomposed with average removal efficiency of −10.2% to 79.4%. PCO displayed a higher degradation activity toward polar VOCs (OVOCs > AHs > AlHs). Furthermore, high non-cancer, cancer risks and occupational exposure cancer risks were found as exposed to the emitted VOCs, and a dramatic reduction of the risks were achieved after treatment. This coupled recovery-decontamination techniques illustrated an excellent recoverability to nonpolar VOCs and efficient decomposition activity to polar VOCs, to eliminate almost emitted VOCs, with promising potential application in atmospheric purification and improvement of occupational environments.