Alamo Nole, Luis A.
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Publication Sorption of VOCs and PAHs onto recycled tire crumb rubber(2011) Alamo Nole, Luis A.; Román-Velázquez, Félix R.; College of Arts and Sciences - Sciences; Perales-Perez, Oscar; Vega, Carmen A.; De Jesús, Marco A.; Department of Chemistry; Colucci Rios, JoséSorption of Volatile Organic Compounds (VOCs) (ethylbenzene, toluene and xylene) and Poly Aromatic Hydrocarbons (PAHs) (acenaphthene, acenaphthylene and phenanthrene) by tire crumb rubber (TCR) and its main components were evaluated: carbon black (CB) and styrenebutadiene polymer (SBP). The initial concentrations of VOCs and PAHs in aqueous solutions ranged from 0.05 mg/L to 100.0 mg/L and 0.03 mg/L and 3.0 mg/L, respectively. The amounts of CB and SBP used in the sorption tests were determined considering their typical contents in tire crumb rubber (30% and 60% w/w, respectively). Freundlich’s isotherms and Scatchard plot parameters suggested a two-step sorption process when TCR was used as the sorbent; whereas a single-step route was apparent when the sorption experiments were carried out with CB or SBP. Freundlich’s ‘n’ parameters for toluene, xylene, acenaphthene and phenanthrene were estimated at 1.018, 0.90, 1.207 and 0.655, respectively using TCR. The maximum uptake capacities (Kf) calculated from Freundlich’s equation for toluene, xylene, acenaphthene and phenanthrene were 0.239 mg/g, 0.723 mg/g, 3.32 mg/g and 54.6 mg/g, respectively, using TCR as the sorbent. In a different set of experiments, the effect of TCR concentration in the sorption of VOCs such as ethylbenzene, toluene and xylene, and PAHs such as acenaphthene, acenaphthylene and phenanthrene was evaluated for single and multi-component experiments. The maximum uptake capacities (Kf) calculated from Freundlich’s equation for ethylbenzene, toluene and xylene for single component experiments were 1.8, 0.17 and 1.9 mg/g, respectively, and the (Kf) for multicomponent experiments were 0.67, 0.35 and 0.81 mg/g, respectively. The (Kf) for acenaphthene, acenaphthylene and phenanthrene for single component experiments were 10.2, 5.02 and 46.9 mg/g, respectively, and the (Kf) for multi-component experiments were 6.23, 4.38 and 11.1 mg/g, respectively. TCR also was used to remove gasoline components from aqueous solutions. The qualitative analysis showed that all components in the gasoline water samples of 30 mg/L were partially removed. The components with high molecular weight were almost completely removed using 5 g/L of TCR. A gas chromatographic analysis using Single Ion Monitoring (SIM) analysis allowed the quantification of the amount of toluene and o-xylene present in the gasoline water samples. The removal (after 6 hours of contact time) of total gasoline compounds was 96%, and the removal of toluene and o-xylene in the gasoline samples was 73% and 86%, respectively, using an initial concentration of 30 mg/L of gasoline and 5.0 g/L of TCR. A modified gas chromatograph and a column packed with 25 g of TCR (mesh 14-20) were used to remove toluene in gas phase. The toluene was injected using a constant syringe pump at rates between 0 and 30 µL/h. Sorption isotherms were constructed by changing the system pressure between 0 and 50 psi. The ‘n’ value and the uptake capacity (Kf) calculated from Freundlich’s equation were 1.19 and 0.54 mg/g, respectively. The uptake capacity for the removal of toluene in gas phase was higher than in the aqueous phase. A modification of TCR using microorganisms was studied. Pseudomona sp. was isolated and immobilized onto TCR to improve its removal capacity against phenanthrene. After 7 days, the modified TCR (1.0 g/L) adsorbed and degraded 92% of phenanthrene. The removal was due to the TCR sorption (90%) and microorganism biodegradation (10%). The sorption capacity and its low cost compared with commercially available sorbents make TCR a promising sorbent for VOCs, PAHs and gasoline components in aqueous and gas phases.Publication Sorption of ethylbenzene, toluene and xylene onto crumb rubber from aqueous solutions(2006) Alamo Nole, Luis A.; Román-Velázquez, Félix R.; College of Arts and Sciencies - Sciences; Perales-Pérez, Oscar; Vega-Olivencia, Carmen A.; Department of Chemistry; Padilla, IngridWaste tires crumb rubber was used to remove ethylbenzene (E), toluene (T) and xylene (X) from aqueous solutions at room temperature. Concentrations of ETX were quantified by GC-MS. Sorption of ETX using different concentrations (10.0, 5.0 1.0, 0.5 and 0.1 g/L) of mesh 14-20 crumb rubber and pH 1.5 and 6.0 were investigated. The removal efficiency was dependent on solution pH and crumb rubber concentrations. Up to 99, 95 and 77% of xylene, ethylbenzene and toluene respectively, were removed from starting 30 mg/L solutions, pH 6 and 10g/L crumb rubber. Uptake capacities of 55, 48 and 24 mg/g rubber for xylene, ethylbenzene and toluene, respectively, were achieved. Decreasing of 5% of removal was observed when the pH was 1.5. The sorption capacity of crumb rubber was xylene > ethylbenzene > toluene, whereas higher crumb rubber concentration enhanced the ETX uptake.