RESUMO
The aim of this paper was to investigate the feasibility of the removal of phosphate from aqueous solution by electro-coagulation (EC). The current density (CD) between 2.5 and 10 mA cm(-2) and duration in the limits of 5-20 min were tried for different concentrations. In order to determine optimal operating conditions, the EC process used for the phosphate removal was examined in dependence with the CD, initial concentrations and time. The results of the experimental batch processing showed high effectiveness of the EC method in removing phosphate from aqueous solutions.
Assuntos
Fosfatos/análise , Fosfatos/química , Poluição Química da Água/análise , Água/química , Eletrocoagulação/métodos , Estudos de Viabilidade , Resíduos Perigosos/análise , Concentração de Íons de Hidrogênio , Concentração Osmolar , SoluçõesRESUMO
Sixty steroid homologues belonging to a series of 17-spirolactone derivatives such as aldosterone antagonists were investigated by electronic-topological method (ETM). Activity features Ph1-Ph3 that also are called pharmacophores were revealed. The pharmacophore Ph1 consists of two oxygen atoms and four carbon atoms. The mineralocorticoid activity appeared to be affected by the distance between the two oxygen atoms. Features AP1-AP3 that are characteristic of inactive compounds (or anti-pharmacophores) were also revealed. Comparative analysis of molecules that include either pharmacophores or anti-pharmacophores was carried out.
Assuntos
Antagonistas de Receptores de Mineralocorticoides/química , Antagonistas de Receptores de Mineralocorticoides/farmacologia , Modelos Químicos , Espironolactona/química , Espironolactona/farmacologia , Animais , Elétrons , Modelos Moleculares , Estrutura Molecular , Potássio/urina , Ratos , Sódio/urina , Relação Estrutura-AtividadeRESUMO
Conformational analysis and quantum chemical calculations were carried out using molecular mechanics (MMP2) and semi-empirical quantum chemistry (CNDO/2) methods for 51 steroid homologues belonging to a series of 17-spirolactones. Matrices called Electronic-Topological Matrices of Conjunction (ETMCs) were formed using data obtained from quantum chemical calculations. A structural fragment of activity was identified in the series of steroids. As seen from the fragment's properties, active compounds are characterized by the presence of two atoms of oxygen, O1 and O3, which are situated at a distance of 13.5 A and possess high negative charges (-0.29 to -0.31 e).