Covalent organic frameworks as highly versatile materials for the removal and electrochemical sensing of organic pollutants.

The presence of persistent organic compounds in water has become a worldwide issue due to its resistance to natural degradation, inducing its environmental resilience. Therefore, the accumulation in water bodies, soils, and humans produces toxic effects. Also, low levels of organic pollutants can lead to serious human health issues, such as cancer, chronic diseases, thyroid complications, immune system suppression, etc. Therefore, developing efficient and economically viable remediation strategies motivates researchers to delve into novel domains within material science. Moreover, finding approaches to detect pollutants in drinking water systems is vital for safeguarding water safety and security. Covalent organic frameworks (COFs) are valuable materials constructed through strong covalent interactions between blocked monomers. These materials have tremendous potential in removing and detecting persistent organic pollutants due to their high adsorption capacity, large surface area, tunable porosity, porous structure, and recyclability. This review discusses various synthesis routes for constructing non-functionalized and functionalized COFs and their application in the remediation and electrochemical sensing of persistent organic compounds from contaminated water sources. The development of COF-based materials has some major challenges that need to be addressed for their suitability in the industrial configuration. This review also aims to highlight the importance of COFs in the environmental remediation application with detailed scrutiny of their challenges and outcomes in the current research scenario.

Mercury remediation from wastewater through its spontaneous adsorption on non-functionalized inverse spinel magnetic ferrite nanoparticles.

In this study, inverse spinel cubic ferrites MFe2O4 (M = Fe2+, and Co2+) have been fabricated for the high-capacity adsorptive removal of Hg(II) ions. The PXRD analysis confirmed ferrites with the presence of residual NaCl. The surface area of Fe3O4 (Fe-F) and CoFe2O4 (Co-F) material was 69.1 and 45.2 m2 g-1, respectively. The Co-F and Fe-F showed the maximum Hg(II) adsorption capacity of 459 and 436 mg g-1 at pH 6. The kinetic and isotherms models suggested a spontaneous adsorption process involving chemical forces over the ferrite adsorbents. The Hg(II) adsorption process, probed by X-ray photoelectron spectroscopy (XPS), confirmed the interaction of Hg(II) ions with the surface hydroxyl groups via a complexation mechanism instead of proton exchange at pH 6 with the involvement of chloride ions. Thus, this study demonstrates a viable and cost-effective solution for the efficient remediation of Hg ions from wastewater using non-functionalized ferrite adsorbents. This study also systematically investigates the kinetics and isotherm mechanism of Hg(II) adsorption onto ferrites and reports one of the highest Hg(II) adsorption capacities among other ferrite-based adsorbents.

Application of hybrid MOF composite in extraction of f-block elements: Experimental and computational investigation.

An attempt was made to understand the sorption behaviour of UO22+, Th4+ and Eu3+ on novel hybrid metal-organic framework composites, FeBDC@CoBDC. The XRD pattern revealed the composite nature of the hybrid MOF materials, while FTIR and Raman spectroscopic analyses evidenced the presence of different functional moieties. The thermal stability of the hybrid MOF composites was investigated through thermogravimetric analysis. The sorption predominantly followed Langmuir isotherm with sorption capacity of 189 mg g-1, 224 mg g-1 and 205 mg g-1 for UO22+, Th4+ and Eu3+ respectively. The sorption proceeded through chemisorption following pseudo 2nd order rate kinetics. The processes were found to be thermodynamically favourable and endothermic in nature. However, they were entropically driven. Multiple contacts of complexing agents were necessary for quantitative elution of f-elements from loaded MOF. The MOF showed moderate stability towards radiation exposure. DFT calculation was used for the optimization of structures, estimation of bond length and estimation of binding energy. In hybrid MOF composites, the Fe atom was having six coordination with 4 O atoms of BDC moieties and 2 O atoms of -OH groups. The O atoms of BDC and -OH groups were coordinated to Eu, Th and U atoms during their sorption.

Efecto del número de controles prenatales sobre los conocimientos de parto y puerperio en primigestas atendidas en el C.U.S.P.P.D, mayo a junio 1993

La presente investigación tiene el propósito de determinar si el nivel de conocimientos sobre parto y puerperio aumenta a medida que aumenta el número de controles prenatales y si sólo 3 controles prenatales (segun norma) son suficientes para incrementar los conocimientos significativamente en las primigestas, para tal efecto se usó el método descriptivo transversal con un diseño de relación, la población estudiada fue de 123 gestantes. Al aplicar el instrumento se orientó y educó a las nuevas madres en relación al parto y puerperio, el muestreo utilizado,fue por convenencia. Para la recolección de datos, se aplicó el formulario de la entrevista estructurada. Indudablemente se ha comprobado que el número de controles aumenta el nivel de conocimientos sobre parto y puerperio, y que 3 controles (según norma) no son suficientes para incrementar los conocimientos sobre parto y puerperio