Decontamination of waters polluted with simazine by sorption on mesoporous metal oxides.

Two mesoporous metal oxides, Al(2)O(3) and Fe(2)O(3), were evaluated as regards their ability to remove simazine, a highly persistent herbicide of s-triazines, using a batch equilibrium method. The effect of several experimental parameters such as pH, contact time, initial concentration and sorbent dosage on the sorption of the herbicide was investigated. The maximum sorption of simazine on Al(2)O(3) and Fe(2)O(3) was observed at pH 6.5 and 3.5, respectively. The different sorption capacities of the two oxides were explained considering a set of factors affecting the sorption process such as the surface area and the porosity. The kinetics of sorption on both oxides was described using a pseudo second-order model. The sorption of simazine on Fe(2)O(3) was faster in comparison to that observed on Al(2)O(3). It was shown that aluminum oxide can be regenerated by incineration, and consequently can be considered for industrial treatment systems designed to mitigate the pesticide pollution in the aquatic environments.

Microbial conversion of olive oil mill wastewaters into lipids suitable for biodiesel production.

Lipomyces starkey were able to survive and proliferate in the presence of olive oil mill wastewaters (OMW), a medium difficult to process by biological treatments, due to the antimicrobial activities of their phenolic components. The microorganisms were grown in the presence of undiluted OMW, without external organic supplements, producing a significant reduction of both the total organic carbon (TOC) and the total phenols content. The OMW treated by L. starkey showed a significant increase of the germination index. The preliminary dilution of OMW enhanced the reduction of polluting components of OMW, leading to a complete TOC removal, as well as to lower levels of residual phenols. The activities of extracellular lipases and esterases significantly increased in the course of the OMW fermentation. A significant increase in lipid yield was observed in L. starkey in the course of the OMW treatment, particularly enhanced when the feedstock was preliminarily diluted. The fatty acid distribution showed a prevalence of oleic acid, demonstrating the potential of L. starkeyi as a source of lipids to be used as a feedstock for the synthesis of II generation biodiesel.

Sorption capacity of mesoporous metal oxides for the removal of MCPA from polluted waters.

A study was performed to assess the sorption capacity of the phenoxy acid herbicide, MCPA, on two mesoporous oxides, Al(2)O(3) and Fe(2)O(3,) by using a batch equilibrium method. Effects of pH, contact time, initial concentration and sorbent dosage on the sorption of the herbicide were investigated. The collected data evidenced the greater sorption efficiency of Al(2)O(3) with respect to Fe(2)O(3). These results can be explained by considering the specific mesoporous structure of Al(2)O(3) together with the greater value of surface area. MCPA is assumed to be bound to Al(2)O(3) and Fe(2)O(3) by a combination of ionic and ion-dipole bonding. Both oxides present as sorbents for a fast and highly efficient removal of MCPA from contaminated waters. For the first time the possible use of mesoporous metal oxides to remove MCPA from contaminated wastewaters identifies these sorbents as suitable filters for the decontamination of point sources.

Comparative study on the sorption capacity of cyhalofop Acid on polymerin, ferrihydrite, and on a ferrihydrite-polymerin complex.

A comparative study was performed on the sorption capacity of the phenoxy acid herbicide cyhalofop on polymerin (from olive oil mill effluents), ferrihydrite, and a ferrihydrite-polymerin complex, by using a batch equilibrium method. The most efficient sorbent showed to be ferrihydrite followed by the ferrihydrite-polymerin complex and polymerin. Cyhalofop acid bound to ferrihydrite by a combination of ionic and ion-dipole bonding, whereas the same herbicide bound to the ferrihydrite-polymerin complex by ionic bonding and to polymerin by hydrogen bonding. Simulated wastewaters contaminated with cyhalofop acid were completely purified by two sorption cycles on ferrihydrite and five cycles on the ferrihydrite-polymerin complex, whereas the same wastewaters maintained a constant residue even after five sorption cycles on polymerin. For the first time, the possible use of a mineral (ferrihydrite) and an organo-mineral complex (ferrihydrite-polymerin) as a filter for the control of the herbicide contamination in point sources is proposed and briefly discussed.