The role of conductive additives on the performance of hybrid carbon xerogels as electrodes in aqueous supercapacitors

Three different hybrid carbon xerogels containing Graphene Oxide (AXGO), Micronized Graphite (AXMG) and Carbon Black (AXCB) were synthesized using an easy, fast and affordable method. These three additives were initially selected to improve the electrical conductivity of the pristine activated carbon xerogel (AX) thus expecting to improve its performance in aqueous supercapacitors. Capacitances of the corresponding devices were measured as a function of current density and results of the high and low charge transfer regime of the supercapacitors were discussed separately. In both regimes, the differences observed between the hybrid electrodes were analyzed on the basis of the concurrent influence of the micro and mesoporosity, surface chemistry and electrical conductivity of the materials. Accordingly, even though all the hybrid carbon xerogels showed higher electrical conductivities, only AXGO rendered a better performance than AX, showing the highest capacitances in the whole interval of intensities studied. Consequently, at 16 A g−1, the energy and power densities of the AXGO supercapacitors increased up to 16% and 97%, respectively, with respect to AX, and of 143% and 409%, respectively, with respect to a commercial activated carbon used as reference. The performance of AXCB and, especially AXMG was worse than AX supercapacitors due to a combination of inadequate pore size distributions and/or a poor surface chemistry. Finally, TEM analysis helped to understand the different way the three additives were affecting the nanostructure (and final properties) of the hybrid carbon xerogels.Authors gratefully acknowledge the financial support from the Ministerio de Economía, Industria y Competitividad from Spain (Project CTQ2017-87820-R). MCR also acknowledges CSIC (Project I.E. 201880E010)

Effectiveness, safety/tolerability of OBV/PTV/r ± DSV in patients with HCV genotype 1 or 4 with/without HIV-1 co-infection, chronic kidney disease (CKD) stage IIIb-V and dialysis in Spanish clinical practice - Vie-KinD study

Limited data are available on the effectiveness and tolerability of direct-acting antivirals (DAAs) therapies in the real world for HCV-infected patients with comorbidities. This study aimed to describe the effectiveness of OBV/PTV/r ± DSV (3D/2D regimen) with or without ribavirin (RBV) in HCV or HCV/HIV co-infected patients with GT1/GT4 and CKD (IIIb-V stages), including those under hemodialysis and peritoneal dialysis in routine clinical practice in Spain in 2015.Non-interventional, retrospective, multicenter data collection study in 31 Spanish sites. Socio-demographic, clinical variables, study treatment characteristics, effectiveness and tolerability data were collected from medical records.Data from 135 patients with a mean age (SD) of 58.3 (11.4) years were analyzed: 92.6% GT1 (81.6% GT1b and 17.6% GT1a) and 7.4% GT4, 14 (10.4%) HIV/HCV co-infected, 19.0% with fibrosis F3 and 28.1% F4 by FibroScan®, 52.6% were previously treated with pegIFN and RBV. 11.1%, 14.8% and 74.1% of patients had CKD stage IIIb, IV and V respectively. 68.9% of patients were on hemodialysis; 8.9% on peritoneal dialysis and 38.5% had history of renal transplant. A total of 125 (96.2%) of 135 patients were treated with 3D, 10 (7.4%) with 2D and 30.4% received RBV. The overall intention-to-treat (ITT) sustained virologic response at week 12 (SVR12) was 92.6% (125/135) and the overall modified-ITT (mITT) SVR12 was 99.2% (125/126). The SVR12 rates (ITT) per sub-groups were: HCV mono-infected (91.7%), HCV/HIV co-infected (100%), GT1 (92.0%), GT4 (100%), CKD stage IIIb (86.7%), stage IV (95%) and stage V (93%). Among the 10 non-SVR there was only 1 virologic failure (0.7%); 4 patients had missing data due lost to follow up (3.0%) and 5 patients discontinued 3D/2D regimen (3.7%): 4 due to severe adverse events (including 3 deaths) and 1 patient´s decision.These results have shown that 3D/2D regimens are effective and tolerable in patients with advanced CKD including those in dialysis with GT 1 or 4 chronic HCV mono-infection and HIV/HCV coinfection in a real-life cohort. The overall SVR12 rates were 92.6% (ITT) and 99.2% (mITT) without clinically relevant changes in eGFR until 12 weeks post-treatment. These results are consistent with those reported in clinical trials

Treatment with tocilizumab or corticosteroids for COVID-19 patients with hyperinflammatory state: a multicentre cohort study (SAM-COVID-19)

Objectives: The objective of this study was to estimate the association between tocilizumab or corticosteroids and the risk of intubation or death in patients with coronavirus disease 19 (COVID-19) with a hyperinflammatory state according to clinical and laboratory parameters. Methods: A cohort study was performed in 60 Spanish hospitals including 778 patients with COVID-19 and clinical and laboratory data indicative of a hyperinflammatory state. Treatment was mainly with tocilizumab, an intermediate-high dose of corticosteroids (IHDC), a pulse dose of corticosteroids (PDC), combination therapy, or no treatment. Primary outcome was intubation or death; follow-up was 21 days. Propensity score-adjusted estimations using Cox regression (logistic regression if needed) were calculated. Propensity scores were used as confounders, matching variables and for the inverse probability of treatment weights (IPTWs). Results: In all, 88, 117, 78 and 151 patients treated with tocilizumab, IHDC, PDC, and combination therapy, respectively, were compared with 344 untreated patients. The primary endpoint occurred in 10 (11.4%), 27 (23.1%), 12 (15.4%), 40 (25.6%) and 69 (21.1%), respectively. The IPTW-based hazard ratios (odds ratio for combination therapy) for the primary endpoint were 0.32 (95%CI 0.22-0.47; p < 0.001) for tocilizumab, 0.82 (0.71-1.30; p 0.82) for IHDC, 0.61 (0.43-0.86; p 0.006) for PDC, and 1.17 (0.86-1.58; p 0.30) for combination therapy. Other applications of the propensity score provided similar results, but were not significant for PDC. Tocilizumab was also associated with lower hazard of death alone in IPTW analysis (0.07; 0.02-0.17; p < 0.001). Conclusions: Tocilizumab might be useful in COVID-19 patients with a hyperinflammatory state and should be prioritized for randomized trials in this situatio

New oxygenated carbonaceous adsorbents prepared by combined radiant/microwave heating for the removal of Pb 2+ in aqueous solution

Abstract This paper presents a new procedure to obtain efficient carbonaceous adsorbents for the removal of Pb2+ in aqueous solution. Experimental procedure includes a pre-treatment of pecan nut shells using radiant heating at low temperatures (280-340 °C), followed by microwave radiation heating (Microwave Assist Technology: MAT) and using a L16 orthogonal array of Taguchi method to find the optimal preparation conditions, setting as the response variable the removal of Pb2+ in aqueous solution. The obtained materials were characterized using elemental analysis, FT-IR spectroscopy, potentiometric titration, nitrogen adsorption isotherms at -196 °C and SEM/EDX analysis. Full Pb2+ adsorption isotherms in aqueous solution were studied using stirred batch systems at 30 °C, pH 5, and using a mass to volume ratio of 2 g/L. The best performing adsorbent rendered an outstanding Pb2+ sorption capacity (261 mg/g), in spite of its rather low porosity. Such a high capacity was explained in terms of the materials surface chemistry, because the obtained carbons have a high amount of acidic and oxygenated groups, as well as calcium deposits. Also, the optimum conditions of each factor level obtained from the orthogonal array allowed to obtain a highly efficient carbon for Pb+2 removal

Graphitized Carbon Xerogels for Lithium-Ion Batteries

Carbon xerogels with different macropore sizes and degrees of graphitization were evaluated as electrodes in lithium-ion batteries. It was found that pore structure of the xerogels has a marked effect on the degree of graphitization of the final carbons. Moreover, the incorporation of graphene oxide to the polymeric structure of the carbon xerogels also leads to a change in their carbonaceous structure and to a remarkable increase in the graphitic phase of the samples studied. The sample with the highest degree of graphitization (i.e., hybrid graphene-carbon xerogel) displayed the highest capacity and stability over 100 cycles, with values even higher than those of the commercial graphite SLP50 used as reference

Reduced Graphene Oxide Aerogels Cartridges for Solid Phase Extraction of Benzotriazoles

UV-benzotriazoles have been identified as water micropollutants that cause serious problems for human health and the environment. Their low concentration in water bodies complicates their detection by direct water analysis, slowing the corrective actions to avoid bioaccumulation. In this regard, the use of graphene-based materials with a high affinity for non-polar molecules has been demonstrated to be a potential tool for the optimal separation and concentration of this type of molecules in solid phase extraction (SPE) processes. This work evaluates the potential of novel reduced graphene oxide aerogels (rGO) as extractants of mixtures of three UV-benzotriazoles in water at low concentrations. These rGO aerogels incorporate graphenic domains into a tough structure of polymeric chains by adding graphene oxide during the synthesis of resorcinol-formaldehyde gels. Aerogels with a different content and ordering of graphenic domains were obtained and characterized using Raman, XRD, SEM and nitrogen adsorption isotherms (&minus;196 &deg;C). The rGO aerogels that performed better as solid phase extractants were those containing 60% rGO. Aerogels with lower rGO contents (40%) required a high-temperature (2000 &deg;C) treatment to render competitive results. The SPE methodology using selected rGO aerogels was optimized by varying the elution solvent, elution time and volume. The best performances, i.e., recoveries of 80&ndash;100% and enrichment factors of 12.5&ndash;50, were accomplished when using 0.8 mL of tetrahydrofuran (THF) as an elution solvent. As a result, a fast (10 min) and simple extraction method of UV-benzotriazoles in water was attained, achieving a detection limit of 1 ng mL&minus;1. Selected aerogels were finally tested for the SPE of spiked samples of river waters, showing a similar performance to that observed with synthetic mixtures

Comparative study of binderless zeolites and carbon molecular sieves as adsorbents for CO2 capture processes

CO2 capture from concentrated sources such as power plants will play an important role in reducing CO2 emissions, contributing to climate change mitigation. Adsorption technology has attracting scientific attention because it offers improved energy efficiency and reduced costs. Two of the most used families of adsorbents in the industry are zeolites and carbon-based adsorbents. This study compares the CO2 separation performance of two promising groups of adsorbents belonging to these families: binderless zeolites and carbon molecular sieves (CMSs). Five adsorption key performance indicators (KPIs), namely adsorption capacity, working capacity, regenerability, selectivity and adsorption selection parameter were obtained from the adsorption isotherms (CO2 and N2; measured at 0-10 bar and 283-323 K) and used to assess the potential of the adsorbents for CO2 capture processes. In general, the KPIs were better for binderless zeolites than for CMSs although CMSs had better regenerability. Zeolites 13XBL and 5ABL were selected as the most promising adsorbents and were tested in a laboratory column set-up for dynamic adsorption of a CO2/N2 mixture (15%/85% v/v), resembling a dry flue gas composition. Simulations of column adsorption experiments were then carried out combining an extended dual-site Langmuir (DSL) model for binary mixtures with Aspen Adsorption™. Binderless zeolite 13XBL showed a higher selectivity with a lower dependence on the pressure and temperature of adsorption, when compared to zeolite 5ABL. These results show that the 13XBL can be considered a good adsorbent for CO2/N2 separations.The authors gratefully acknowledge the funding provided by the company GasN2 and the knowledge and enterprise department of the Catalan government through its Industrial Doctorate program to support this research project (AGAUR, Doctorats Industrials 2014 DI-057). Special thanks to graduates students Carlos Arregui and Guillermo Parladé for their help and support provided with the modeling and master student Albert Melis for the support with column experiments. GESPA group has been recognized as Consolidated Research Group by the Catalan Government with code 2017-SGR-1016. The authors gratefully acknowledge the financial support received from the Ministerio de Ciencia e Innovación (MCIN/AEI/10.13039/501100011033, Project PID2020-115334GB-I00) and Principado de Asturias (FICYT)-European Union (FEDER) (Project PCTI-Asturias IDI/2021/000015). Miguel Montes is member of the SusPlast PTI+ platform of the Spanish National Research Council (CSIC).Peer reviewe