Examinando por Autor "Martinez, Fernando"

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Increasing biodegradability of a real amine-contaminated spent caustic problematic stream through WAO and CWAO oxidation using a high specific surface catalyst from petcoke
(Elsevier, 2023) González, Carlos; Pariente, María Isabel; Molina, Raúl; Espina, L.G.; Masa, María; Bernal, Vicente; Melero, Juan Antonio; Martinez, Fernando
Different operating conditions of wet air oxidation and catalytic wet air oxidation have been studied for the treatment of highly concentrated methyldiethanolamine wastewater streams from amine units of acid gas recovery in petrol refineries. These units occasionally generate streams of high methyldiethanolamine content that require special actions to avoid undesirable impacts on the downstream biological process of the petrochemical wastewater treatment plant due to its inhibition effect. The wet air oxidation treatment achieved remarkable removals of methyldiethanolamine, sulfides, chemical oxygen demand and total organic carbon (99%, 95%, 65% and 38%, respectively). Likewise, activated petroleum coke materials from the own refinery plant were tested as catalysts in the process. These materials were prepared under different conditions (chemical activating agent and thermal carbonization process). The catalytic wet air oxidation treatment using an activated petroleum coke was able to remove the methyldiethanolamine at milder operation conditions keeping a similar performance in terms of wastewater treatment removals as compared to the non-catalytic experiments. This technology significantly increased the biodegradability of the treated effluents ranging from 25 to 70 % due to the formation of more biodegradable substrates (acetic acid and ammonium) for further biological treatment.
Nanocomposite of crystalline Fe2O3 and CuO particles and mesostructured SBA-15 silica as an active catalyst for wet peroxide oxidation processes
(ELSEVIER, 2006) Melero, Juan A.; Calleja, Guillermo; Martinez, Fernando; Molina, Raul
Crystalline Fe2O3 and CuO particles have been incorporated into surfactant-templated SBA-15 materials by direct synthesis. Activity and stability of this material were evaluated on the wet peroxide oxidation of phenol under mild reaction conditions. Its catalytic performance was monitored in terms of total organic carbon (TOC) conversion. The stability was determined by careful measurements of metal leaching into the aqueous solution. The presence of copper prevents the leaching of iron species and increases TOC degradation as compared with those materials containing only crystalline Fe2O3 particles. Moreover, the treatment of iron-copper composite materials under controlled acidic conditions in the presence of hydrogen peroxide leads to the stabilization of metallic species, maintaining TOC degradation rates similar to the fresh catalyst. Thus, this work introduces a new material with interesting properties as Fenton-like catalysts in advanced oxidation processes for pollutant abatement in wastewaters.
Thermal hydrolysis of solid fraction reduces waste disposal and provides a substrate for anaerobic photobiological treatment of refinery wastewater
(Royal Society of Chemistry, 2023-02-15) Jerez, Sara; San Martín, Javier; Ventura, Maria; Pariente, Maria Isabel; Segura, Yolanda; Puyol, Daniel; Molina, Raúl; Melero, Juan Antonio; Martinez, Fernando
Oil refineries generate vast amounts of refinery wastewater (RWW) and oily sludge (OS). Conventional treatments typically manage these effluents separately, and resource recovery potential is not considered. The thermal hydrolysis (TH) of oily sludge at different temperatures from 175 to 200 °C and several hydrolysis times from 30 to 90 minutes has been assessed. The TH reduced the solid fraction of the oily sludge by up to 50% and released substrates in the liquid stream with up to 14 g L−1 of soluble chemical oxygen demand (SCOD) and 592 mg L−1 of NH4+-N. Additionally, the hydrolyzed fraction was assessed as a substrate for the biological treatment of the refinery wastewater. An anaerobic photobiological system based on purple phototrophic bacteria (PPB) was considered to evaluate the co-treatment of both effluents. Batch experiments showed a 10- to 30-fold enhancement of the biomass yield, using both the RWW and the hydrolyzed fraction of the oily sludge. The less energetic TH conditions in terms of temperature and operation time produced the most biodegradable hydrolyzed stream with biomass yields close to those obtained for the control under optimal growth conditions. These results demonstrate the feasibility of the proposed integrated strategy to reduce the solid fraction of the oily sludge by the TH process and to release soluble substrates for a novel anaerobic photobiological treatment along with the RWW.