The adsorption of amino acids onto minerals in prebiotic seas may have played an important role for their protection against hydrolysis and formation of polymers. In this study, we show that the adsorption of the prebiotic amino acids, glycine (Gly), α-alanine (α-Ala) and β-alanine (β-Ala), onto Na+-montmorillonite was dependent on salinity and pH. Specifically, adsorption decreased from 58.3–88.8 to 0–48.9% when salinity was increased from 10 to 100–150% of modern seawater. This result suggests reduced amino acid adsorption onto minerals in prebiotic seas, which may have been even more saline than the tested conditions. Amino acids also formed complexes with metals in seawater, affecting metal adsorption onto Na+-montmorillonite, and amino acid adsorption was enhanced when added before Na+-montmorillonite was exposed to high saline solutions. Also, the dissolution of Na+-montmorillonite was reduced in the presence of amino acids, with β-Ala being the most effective. Thus, prebiotic chemistry experiments should also consider the integrity of minerals in addition to their adsorption capacity.

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Although landfills are generally an environmentally safe option for the disposal of solid waste, the treatment and management of landfill leachate are still critical. The aim of this work was to study through physical-chemical analyses the effects of leachate on the effluent of the sewage treatment plant to which it is disposed on both study sites. The results were compared with those of existing studies, current legislation, municipal waste management practices, and landfill operations. Ethinylestradiol analyses were also performed on the influent and effluent from the sewage treatment plant. The results showed that the landfill leachate has a polluting potential, being found parameters above the allowed value, such as chemical oxygen demand (3,510.33 mg L −1), chloride (3,631.78 mg L −1), and manganese (21.61 mg L −1). The properties of the leachate indicated that the landfill was still in the acid formation phase and did not influence the influent that reached the sewage treatment plant in any way. Ultimately, the quality of the discharged wastewater met all of the predischarge regulatory criteria for materials being sent to a receiving water body, except for the chloride parameter that is not being treated at all.

Este trabalho é uma parceria com uma empresa de produtos oftálmicos que gera efluentes contendo uma mistura de três corantes dispersos: azul 56, amarelo 54 e vermelho 60, todos da classe das antraquinonas. Os corantes dessa classe são resistentes a degradação devido a sua estrutura aromática, a qual retêm a cor por longos períodos de tempo. O tratamento destes corantes é de extrema importância devido à sua toxicidade, podendo apresentar comportamento cancerígeno e mutagênico. O objetivo deste trabalho foi oxidar os compostos orgânicos poluentes usando processos oxidativos avançados. Para isso, foram realizadas eletrólises a corrente constante usando eletrodos de óxidos como catalisadores heterogêneos juntamente com o reagente de Fenton (Fe2+ + H2O2). A descoloração e oxidação foram monitoradas por espectrometria UV-Visível, cromatografia líquida de alta eficiência e carbono orgânico total. O tratamento aplicado permitiu uma rápida degradação dos grupos cromóforos e houve grande influência da concentração do peróxido de hidrogênio na velocidade dessa degradação. Os resultados foram satisfatórios, uma vez que a coloração foi eliminada e os produtos da oxidação identificados não apresentam toxicidade e podem facilmente tratados por métodos tradicionais.

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