RESUMO
Water pollution due to global economic activity is one of the greatest environmental concerns, and many efforts are currently being made toward developing materials capable of selectively and efficiently removing pollutants and contaminants. A series of ß-ketoenamine covalent organic frameworks (COFs) have been synthesized, by reacting 1,3,5-triformylphloroglucinol (TFP) with different C2-functionalized and nonfunctionalized diamines, in order to evaluate the influence of wall functionalization and pore size on the adsorption capacity toward dye and heavy metal pollutants. The obtained COFs were characterized by different techniques. The adsorption of methylene blue (MB), which was used as a model for the adsorption of pharmaceuticals and dyes, was initially evaluated. Adsorption studies showed that -NO2 and -SO3H functional groups were favorable for MB adsorption, with TpBd(SO3H)2-COF [100%], prepared between TFP and 4,4'-diamine- [1,1'-biphenyl]-2,2'-disulfonic acid, achieving the highest adsorption capacity (166 ± 13 mg g-1). The adsorption of anionic pollutants was less effective and decreased, in general, with the increase in -SO3H and -NO2 group content. The effect of ionic interactions on the COF performance was further assessed by carrying out adsorption experiments involving metal ions. Isotherms showed that nonfunctionalized and functionalized COFs were better described by the Langmuir and Freundlich sorption models, respectively, confirming the influence of functionalization on surface heterogeneity. Sorption kinetics experiments were better adjusted according to a second-order rate equation, confirming the existence of surface chemical interactions in the adsorption process. These results confirm the influence of selective COF functionalization on adsorption processes and the role of functional groups on the adsorption selectivity, thus clearly demonstrating the potential of this new class of materials in the efficient and selective capture and removal of pollutants in aqueous solutions.
RESUMO
The paradigm of the treatment of esophageal cancer has been changing with the increasing use of minimally invasive esophagectomy (MIE) in detriment of open esophagectomy (OE). We aimed to perform a meta-analysis to evaluate and compare these two techniques in terms of mortality and associated complications. The literature search was conducted in MEDLINE and U.S. National Library of Medicine Clinical Trials, considering eligible articles since 2015 to 2020. Clinical trials and observational studies were included. We presented results as mean differences with 95% confidence intervals and calculation of heterogeneity associated to the included studies. Thirty-one articles were included with a total of 34,465 participants diagnosed with esophageal adenocarcinoma or squamous cell carcinoma. MIE had tendency towards a decrease in 30- and 90- day mortality after surgery, but no statistically significative results were found. Major cardiovascular and respiratory complications were less frequent in the MIE group, despite high heterogeneity. Also, MIE might contribute to a decrease of minor post-operative complications, to an increase need of a second surgical intervention, to a greater risk for vocal cord lesions; but these results were not statistically significant. Additionally, no differences were found concerning risk of wound infection and for local and systemic recurrence. MIE may be more beneficial than OE, but these findings should be considered carefully.