Improved Removal of Indoor Volatile Organic Compounds by Activated Carbon Fiber Filters Calcined with Copper Oxide Catalyst

Abstract

Heating, ventilating, and air-conditioning (HVAC) systems ensure indoor air quality and provide a comfortable environment. However, the conventional HVAC systems only provide indoor ventilation and adjust temperature and humidity. This work removes indoor volatile organic compounds (VOCs) using a feasible and novel air-cleaning for an HVAC system, to remove indoor VOCs. An activated carbon-fiber (ACF) filter calcined with copper oxide (CuO) catalyst, called a CuO/ACF catalyst filter, was the developed kit. Formaldehyde, a major VOC, was chosen as the target pollutant. Experiments were performed to confirm the filtration ability of the CuO/ACF catalyst filter in removing formaldehyde in a stainless-steel chamber equipped with a simplified HVAC system. Total air exchange rate (ACH) was controlled at 0.5 and 1.0 h À1 , the fresh ACH was 0.15 and 0.30 h À1 , and relative humidity (RH) was set at 30 and 70%. A first-order decay of formaldehyde existed in the controlled chamber when the two pretreated CuO/ACF catalyst filters were employed. Experimental results demonstrate that the CuO/ACF catalyst filters removed formaldehyde effectively. The decay constant was 0.425 and 0.618 h À1 for 0.5 and 2.0 ppm formaldehyde, respectively. Moreover, the formaldehyde decay rate increased as total ACH, fresh ACH, RH, and the Cu(NO 3 ) 2 concentration for calcination of CuO/ACF catalyst filter increased.

A Review of Some Representative Techniques for Controlling the Indoor Volatile Organic Compounds

“…ACF does not contain impurities that can catalyze oxidative reactions and lead to decomposition of the adsorbate within the adsorbent (Das et al, 2004). Accordingly to the previous studies, ACF filters are very good VOC adsorbents, to show improved performance relative to granular activated carbon, zeolites, and silica gel under identical operation conditions (Huang et al, 2010;Das et al, 2004;Liu, 1992).…”

“…Adsorption process is one of the most efficient and safest processes to remove VOCs from indoor air (Bastani et al, 2010;Benne and Griffith, 2009 erative properties (Huang et al, 2010;Yao et al, 2009a;Haghighat et al, 2008;Das et al, 2004). ACF is generally made from rayon, polyacrylonitrile (PAN), or phenolic resin (Huang et al, 2010).…”

“…ACF is generally made from rayon, polyacrylonitrile (PAN), or phenolic resin (Huang et al, 2010). The fibers are woven into a fabric and then activated in steam or CO 2 at high temperatures (e.g., 800� C).…”

“…, with a typical value of 1800 m 2 g -1 (Huang et al, 2010;Lorimier et al, 2005;Das et al, 2004). ACF does not contain impurities that can catalyze oxidative reactions and lead to decomposition of the adsorbate within the adsorbent (Das et al, 2004).…”

“…Huang et al (2010) studied the performance of ACF with a mixture of VOC (a molecular weight of 30 to 156 and boiling point of -21 to 196� C). The time-averaged removal efficiency of all except formaldehyde was above 70 percent, while that of formaldehyde was approximately 20 percent.…”