A Comparative Study Between High Density Polyethylene, Polyurethane Foam and Amberlite XAD-2 in the Removal of Different PAHs

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are classified as persistent organic pollutants found in all environmental compartments and in certain concentrations may present health risks. This work compared the performance of high density polyethylene (HDPE) and polyurethane foam (PUF) for the removal of PAHs naphthalene (NAP), acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene (ANT), and chrysene (CHR) from individual aqueous solutions, relative to Amberlite XAD-2. Batch studies were performed at 20 °C and monitored via UV-Vis spectrophotometry. The effect of the organic modifier, amount of adsorbent, capacity, and adsorption kinetics were investigated. Using 10% acetonitrile as the organic modifier, the removal of ANT and CHR was greater than 90% in 0.5 g of HDPE and PUF. By reducing the amount of the three adsorbents to 0.1 g, the removal percentages did not change significantly – they remained above 90% for most PAHs. The greatest differences were for the CHR, which decreased from 87.5% to 37.6% in HDPE, 91.4% to 63.8% with PUF, and 86.9% to 47.8% in XAD-2. The adsorption capacity in the range of 0–180 min was governed by two stages: the first occurred within 60 min, where the sorption rates were higher; and the second, between 60 and 180 min, where practically no variations occurred. Kinetic data were analyzed by the pseudo-first order, pseudo-second order, and Weber and Morris models. With the exception of NAP, the pseudo-second-order model applies to all compounds. The values of k₂ ranged from 0.19 to 1.46 (g mg⁻¹min⁻¹) in HDPE, between 0.19 and 2.96 (g mg⁻¹min⁻¹) for PUF and 0.10 and 3.20 (g mg⁻¹min⁻¹) in XAD-2. The results demonstrate the viability of the HDPE and PUF polymers as easily available alternative materials to XAD-2.

Keywords:

• Adsorption
• kinetics
• polycyclic aromatic hydrocarbons