title: Evaluation of low-cost materials for sorption of hydrophobic organic pollutants in stormwater.
abstract: Conventional stormwater treatment techniques such as sedimentation and filtration are inefficient for removing the dissolved and colloidal phases of hydrophobic organic compounds (HOCs) present in stormwater. Adsorption could be a promising technique for removing colloidal and dissolved pollutants. Five low-cost sorbent materials were investigated in this project, including two minerals – vermiculite and perlite – and three waste products – two pine barks and a sawdust – as potential adsorbents for removal of polycyclic aromatic hydrocarbons (PAHs), alkylphenols and phthalates; HOCs commonly found in stormwater. Adsorption capacity and kinetics were studied through batch adsorption tests using synthetic stormwater spiked with a mixture of HOCs. Vermiculite and perlite exhibited insignificant removal of the organic contaminants. The three wood-based materials retained >80% of the initial HOC concentration (10-300 μg/L). The two barks exhibited slightly higher adsorption capacities of HOCs than the sawdust. For all compounds tested, maximum adsorption onto the wood-based media was reached in <10 min. The highest adsorption capacity was found for PAHs (up to 45 μg/g), followed by alkylphenols and phthalates. No correlation was found between adsorption capacity and physical-chemical parameters such as solubility and partition coefficients (log K(ow)). Agreement between empirical data and the pseudo-second order kinetic model suggest chemisorption of HOCs onto a monolayer on wood-based media. This could lead to early saturation of the materials and should be investigated in future studies through repeated adsorption of HOCs, for example in column studies.
authors.affiliation: Department of Civil Engineering, University of British Columbia, 6250 Applied Science Lane, Vancouver, BC V6T 1Z4, Canada; Department of Civil and Environmental Engineering, Chalmers University of Technology, Sven Hultins Gata 8, 41296 Göteborg, Sweden. Electronic address: karin@civil.ubc.ca.
authors.forename: Karin
authors.initials: K
authors.lastname: Björklund
authors.affiliation: Department of Civil Engineering, University of British Columbia, 6250 Applied Science Lane, Vancouver, BC V6T 1Z4, Canada.
authors.forename: Loretta
authors.initials: L
authors.lastname: Li
mesh_terms: D000327:Adsorption; D000537:Aluminum Oxide / Q000737:chemistry*; D000538:Aluminum Silicates / Q000737:chemistry*; D005374:Filtration; D057927:Hydrophobic and Hydrophilic Interactions; D010795:Phthalic Acids / Q000032:analysis / Q000737:chemistry; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D014866:Waste Products; D014873:Water Pollutants / Q000032:analysis / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D000538:Aluminum Silicates; D010795:Phthalic Acids; D011084:Polycyclic Aromatic Hydrocarbons; D014866:Waste Products; D014873:Water Pollutants; C003076:Perlite; C003760:vermiculite; C032279:phthalic acid; D012822:Silicon Dioxide; D000537:Aluminum Oxide
keywords: Adsorption filter; Alkylphenols; PAHs; Phthalates; Pine bark; Stormwater management