RESUMEN
Syntheses of the heavy chalcogen-containing alumoxanes [(Me)LAl(SeH)]2(µ-O) (4) and ((Me)LAl)2(µ-Te)(µ-O) (7) were accomplished by the reaction of ((Me)LAlH)2(µ-O) (2; (Me)L = HC[(CMe)N(2,4,6-Me3C6H2)]2(-)) with either red selenium or metallic tellurium. The aluminum hydrogenselenide [(Me)LAl(SeH)]2(µ-Se) (3) was also prepared from the reaction of red selenium and (Me)LAlH2 (1). All compounds were characterized by spectroscopic methods and X-ray diffraction studies. Density functional theory calculations were performed on 4 and 7.
RESUMEN
Metal-humic acid complexes were synthesized and immobilized by a granulation process in anaerobic sludge for their application as solid-phase redox mediators (RM) in the biotransformation of iopromide. Characterization of Ca- and Fe-humic acid complexes revealed electron accepting capacities of 0.472 and 0.556milli-equivalentsg(-1), respectively. Once immobilized, metal-humic acid complexes significantly increased the biotransformation of iopromide in upflow anaerobic sludge blanket (UASB) reactors. Control UASB reactor (without humic material) achieved 31.6% of iopromide removal, while 80% was removed in UASB reactors supplied with each metal-humic acid complex. Further analyses indicated multiple transformation reactions taking place in iopromide including deiodination, N-dealkylation, decarboxylation and deacetylation. This is the first successful application of immobilized RM, which does not require a supporting material to maintain the solid-phase RM in long term operation of bioreactors. The proposed redox catalyst could be suitable for enhancing the redox conversion of different recalcitrant pollutants present in industrial effluents.