Scheda di dettaglio – i prodotti della ricerca
| Dato | Valore |
|---|---|
| Title | Used tires and commercial polymers as the partitioning phase in solid-liquid tppbs (two phase partitioning bioreactors)applied to xenobiotic removal |
| Abstract | -The Two phase partitioning bioreactors (TPPBs) have proven to be an effective technology in reducing toxicity arising from high xenobiotic concentrations in biodegradation processes. The selective partitioning of target molecules is the rationale behind the design and operation of TPPBs which are characterized by a cell-containing aqueous phase, and a second immiscible phase (organic solvent or solid polymer) that acts to selectively sequester toxic molecules and to deliver toxic substrates to the biocatalyst based on cell demand. In the bioremediation of water, where mixed cultures are necessarily utilized, the use of polymers as the sequestering phase is extremely advantageous as polymers are completely biocompatible and inert with respect to the biomass. This feature avoids possible parallel solvent biodegradation that could decrease the removal efficiency in liquid-liquid TPPBs. An additional advantage of polymers is their low cost in comparison to organic solvents. Commercial polymers have been successfully applied as partitioning phases in TPPBs for the removal of PAHs, PCBs, BTX and substituted phenols. Recently, a new opportunity for this technology has been identified, via the use of recycled polymeric materials i.e. used automobile tires as the partitioning phase. In this paper waste tires in small pieces (3-4 mm) and a commercial polymer Tone P787 (Dow Chemical) in the form of roughly spherical beads (~4 mm diameter) were utilized as the sorption phase for the degradation of 2,4-dichlorophenol (DCP), a highly toxic (EC50 = 5-40 mg/L) compound, found in many industrial effluents (i.e. production of pesticides and herbicides). Sorption tests for DCP were performed to verify the related uptake rates from tires and Tone: kinetic parameters were calculated from the data fitting. A mixed culture was acclimatized to DCP in a lab scale fed batch reactor for a 3 month period, and the biomass was subsequently utilized in biodegradation tests with and without a partitioning phase. Both of the two phase systems exhibited a marked reduction of the DCP concentration in the aqueous phase and of the toxic effect. It was observed in batch kinetic tests that, for an initial concentration of 125 mg/L and a reaction time of 500 min, in the conventional single phase reactor, the biomass was strongly inhibited showing a very low removal efficiency (17%) while a significant toxicity abatement was observed in the two phase systems that were able to achieve removal efficiencies of 65% and 83% with tires and Tone respectively. |
| Source | CEST2011 12th International Conference on Environmental Science and Technology, Rodi Grecia, 08/09/2011 |
| Keywords | xenobiotic removal; tires; polymers |
| Year | 2011 |
| Type | Contributo in atti di convegno |
| Authors | Tomei M.C. , Annesini M.C., Daugulis A.J. |
| Text | 342497 2011 xenobiotic removal; tires; polymers Used tires and commercial polymers as the partitioning phase in solid liquid tppbs two phase partitioning bioreactors applied to xenobiotic removal Tomei M.C. , Annesini M.C., Daugulis A.J. Universita La Sapienza roma Italia Queen s University Kingston Ontario Canada The Two phase partitioning bioreactors TPPBs have proven to be an effective technology in reducing toxicity arising from high xenobiotic concentrations in biodegradation processes. The selective partitioning of target molecules is the rationale behind the design and operation of TPPBs which are characterized by a cell containing aqueous phase, and a second immiscible phase organic solvent or solid polymer that acts to selectively sequester toxic molecules and to deliver toxic substrates to the biocatalyst based on cell demand. In the bioremediation of water, where mixed cultures are necessarily utilized, the use of polymers as the sequestering phase is extremely advantageous as polymers are completely biocompatible and inert with respect to the biomass. This feature avoids possible parallel solvent biodegradation that could decrease the removal efficiency in liquid liquid TPPBs. An additional advantage of polymers is their low cost in comparison to organic solvents. Commercial polymers have been successfully applied as partitioning phases in TPPBs for the removal of PAHs, PCBs, BTX and substituted phenols. Recently, a new opportunity for this technology has been identified, via the use of recycled polymeric materials i.e. used automobile tires as the partitioning phase. In this paper waste tires in small pieces 3 4 mm and a commercial polymer Tone P787 Dow Chemical in the form of roughly spherical beads 4 mm diameter were utilized as the sorption phase for the degradation of 2,4 dichlorophenol DCP , a highly toxic EC50 = 5 40 mg/L compound, found in many industrial effluents i.e. production of pesticides and herbicides . Sorption tests for DCP were performed to verify the related uptake rates from tires and Tone kinetic parameters were calculated from the data fitting. A mixed culture was acclimatized to DCP in a lab scale fed batch reactor for a 3 month period, and the biomass was subsequently utilized in biodegradation tests with and without a partitioning phase. Both of the two phase systems exhibited a marked reduction of the DCP concentration in the aqueous phase and of the toxic effect. It was observed in batch kinetic tests that, for an initial concentration of 125 mg/L and a reaction time of 500 min, in the conventional single phase reactor, the biomass was strongly inhibited showing a very low removal efficiency 17% while a significant toxicity abatement was observed in the two phase systems that were able to achieve removal efficiencies of 65% and 83% with tires and Tone respectively. Published version CEST2011 12th International Conference on Environmental Science and Technology Rodi Grecia 08/09/2011 Internazionale Contributo Contributo in atti di convegno mariaconcetta.tomei TOMEI MARIA CONCETTA TA.P07.002.005 Rimozione di composti xenobiotici da acque di scarico |