Valorisation of polyolefins into magnetic carbon nanotubes: application as catalysts in wet peroxide oxidation of paracetamol

This work deals with the application of magnetic carbon nanotubes (MCNTs) in the catalytic wet peroxide oxidation (CWPO) of paracetamol (PCM), a pharmaceutical compound selected as model contaminant of emerging concern (CEC). MCNTs were synthetized by catalytic chemical vapor deposition (CCVD) at 850 ºC, considering low-density polyethylene (LDPE), high-density polyethylene (HDPE), and polypropylene (PP) as carbon precursors representative of urban plastic solid waste. Magnetite supported in alumina (Fe3O4@Al2O3) nanoparticles previously synthesized by sol-gel were used as catalysts in the CCVD process. The synthesized MCNTs were tested in the CWPO of PCM at 80 ºC, monitoring during 24 h the concentration of H2O2, PCM, Total Organic Carbon (TOC) and aromatic compounds. All MCNT catalysts show activity allowing to decompose completely the pharmaceutical in aqueous solutions after 360 min. In particular, the MCNTs synthesized from HDPE lead to complete removal of the pollutant after 30 min of reaction. By TOC analysis, it was observed that the CNTs led to obtain mineralization degrees higher than 38% of the pollutant after 24 h. Aromaticity test indicated that the catalyst prepared from HDPE promotes more degradation of the intermediates than the catalyst prepared from LDPE and PP.This work was financially supported by project "PLASTIC_TO_FUEL&MAT – Upcycling Waste Plastics into Fuel and Carbon Nanomaterials" (PTDC/EQU-EQU/31439/2017) and CIMO (UIDB/00690/2020) through FEDER under Program PT2020. Fernanda F. Roman acknowledges the national funding by FCT through the individual research grant SFRH/BD/143224/2019.info:eu-repo/semantics/publishedVersio

Selective denitrification of lipophilic pollutants from oily wastewater by peroxidation using Janus-structured amphiphilic carbon nanotubes as catalysts

Carbon nanotubes (CNTs) were tested as catalysts in the selective denitrification of 4-nitrophenol (4-NP) from oily wastewater by catalytic wet peroxide oxidation (CWPO). The CNTs were prepared by chemical vapor deposition, feeding sequentially ethylene (E) and/or acetonitrile (A) during different times until 20 min, resulting in samples E20, A20 and E10A10, the number denoting the time feeding of each precursor and the order of appearance of the letter indicating the order of each precursor. The synthesized CNTs were tested in the CWPO of 4-NP in aqueous solutions and in simulated oily wastewater (2,2,4-trimethylpentane and water) at 80 ºC, initial pH 3.5, C4-NP = 1 g L-1, CH2O2 = 3.56 g/L and Ccatalyst = 2.5 g L-1. The catalyst A20 promoted a faster decomposition of H2O2 and a lower degradation of 4-NP in the aqueous system, whereas the catalyst E20 displayed the opposite trend, since E20 was able to remove 99% of the pollutant and A20 only 69% after 8 h of reaction. E10A10 in biphasic L-L media presented the highest conversion of 4-NP after 24 h in the oily phase (51%), followed by A20 (38%) and then E20 (25%). This tendency may be ascribed to the formation of Pickering emulsions by E10A10. The amphiphilic carachteristic of this material ensures a closer contact between the liquid phases, allowing higher mass transfer.This work was financially supported by project "PLASTIC_TO_FUEL&MAT – Upcycling Waste Plastics into Fuel and Carbon Nanomaterials" (PTDC/EQU-EQU/31439/2017), Base Funding - UIDB/50020/2020 of the Associate Laboratory LSRE-LCM - funded by national funds through FCT/MCTES (PIDDAC), and CIMO (UIDB/00690/2020) through FEDER under Program PT2020. Fernanda F. Roman acknowledges the national funding by FCT, Foundation for Science and Technology, and FSE, European Social Fund, through the individual research grant SFRH/BD/143224/2019.info:eu-repo/semantics/publishedVersio

Degradation of paracetamol by wet peroxide oxidation using carbon nanotubes synthesized from plastic solid waste

Within increased production and economic/social dependence of plastic utilization, an environmental problem has also emerged. In this scenario, plastic solid waste (PSW) recycling/management/recovery has become a problem of public concern, with a global generation estimated at 150 million tonnes per year. Materials produced from PSW can be classified as primary (performance/characteristics equivalent to virgin plastic), secondary (performance’s requirement lower than the original application), tertiary (PSW used as feedstock for the generation of chemicals and fuels), and quaternary (energy recovery via incineration) recycled materials [1]. For instance, pyrolysis of PSW has been extensively used for the thermochemical conversion of useless PSW into oil, gas, and carbon materials, thus classified as terciary recycled material.Adriano S. Silva thanks his doctoral Grant with reference SFRH/BD/151346/2021 financed by the Portuguese Foundation for Science and Technology (FCT), with funds from NORTE2020, under MIT Portugal Program. This work was financially supported by UIDB/05757/2020 (CeDRI), UIDB/00690/2020 (CIMO), LA/P/0045/2020 (ALiCE), UIDB/50020/2020, UI-DP/50020/2020 (LSRE-LCM) and funded by national funds through FCT/MCTES (PIDDAC). Fernanda F. Roman acknowledges the national funding by FCT through the individual research grant SFRH/BD/143224/2019info:eu-repo/semantics/publishedVersio

Selective oxidation of 4-nitrophenol with H2O2 in a biphasic system by janus-like carbon nanotubes

The use of petroleum-based products has increased drastically with the increase in population, resulting in the deposition of oily products in aquatic systems. It is estimated that for each ton of petroleum that undergoes refinement processes, between 0.5 and 1 ton of oily wastewaters are generated, bearing an oil concentration that may reach 40 g L-1 [1,2]. Hazardous pollutants dissolved both in oily and aqueous phases may also be found in those oily wastewaters [3], hindering their treatment through conventional processes. Furthermore, the oil phase is, in some cases, an added-value product, and its degradation results in economic losses. Thus, the development of processes that allow the removal of hazardous contaminants from oily and aqueous phases, providing an opportunity for recovering both phases, should be advantageous [3]. This work deals with the selective removal of a hazardous compound (4-nitrophenol, 4-NP) from a simulated oily wastewater (2,2,4-trimethylpentane:water = 10:90 v/v) by an oxidative process considering H2O2 as oxidant and amphiphilic Janus-like carbon nanotubes as catalysts. Amphiphilic catalysts were selected since they should present advantages in this process due to their ability to interact with both aqueous and oily compounds and phases [4]This work was financially supported by project "PLASTIC_TO_FUEL&MAT – Upcycling Waste Plastics into Fuel and Carbon Nanomaterials" (PTDC/EQU-EQU/31439/2017), Base Funding - UIDB/50020/2020 of the Associate Laboratory LSRE-LCM - funded by national funds through FCT/MCTES (PIDDAC), and CIMO (UIDB/00690/2020) through FEDER under Program PT2020. Fernanda F. Roman acknowledges the national funding by FCT, Foundation for Science and Technology, and FSE, European Social Fund, through the individual research grant SFRH/BD/143224/2019.info:eu-repo/semantics/publishedVersio

Selective denitrification of simulated oily wastewater by oxidation using Janus-structured carbon nanotubes

The intense industrial development has resulted in several consequences for human and environmental health, including the increased discharge of oily products in water bodies. Oily products are widely used in industry, often bearing an associated high cost. Finding alternatives to treat oily wastewater aiming at recovering oily and water phases is an approach allowing recovery of products of economic interest. In this work, Janus-like carbon nanotubes (CNTs) were synthesized by varying the feed time of acetonitrile and ethylene, respectively, as nitrogen/ carbon and carbon precursors in a chemical vapor deposition (CVD) approach. The CVD approach allowed the synthesis of completely undoped, completely doped and partially doped CNTs with a Janus structure. The CNTs were then tested as catalysts for the selective oxidation of 4-nitrophenol (4-NP) contained in a simulated oily wastewater (2,2,4-trimethylpentane/water (O/W) = 1:9, volume basis) by catalytic wet peroxide oxidation (CWPO). The CWPO experiments were conducted for 24 h, 80 ◦C, 2.5 g L-1 of catalyst, and the stoichiometric concentration of H2O2 (3.6 g L-1) for the degradation of 4-NP (1 g L-1). The same conditions were kept for experiments conducted under a biphasic system. The catalysts bearing a Janus-like structure were demonstrated to be more effective in CWPO experiments in aqueous-only and biphasic systems for the abatement of 4-NP.This work was financially supported by LA/P/0045/2020 (ALiCE), UIDB/50020/2020 and UIDP/50020/2020 (LSRE-LCM) funded by national funds through FCT/MCTES (PIDDAC); project “PLASTIC_TO_FUEL&MAT – Upcycling Waste Plastics into Fuel and Carbon Nanomaterials” (PTDC/EQU-EQU/31439/2017), CIMO (UIDB/00690/2020), and project “Healthy Waters” (NORTE-01–0145-FEDER-000069) through FEDER under Program PT2020. Fernanda F. Roman acknowledges the Foundation for Science and Technology (FCT) and the European Social Fund (FSE) for the individual research grant with reference SFRH/BD/143224/2019. Adriano S. Silva was supported by the doctoral Grant SFRH/BD/151346/2021 financed by FCT with funds from NORTE2020, under MIT Portugal Program. Jose L. Diaz De Tuesta acknowledges the financial support through the program of Atracción al Talento of Comunidad de Madrid (Spain) for the individual research grant 2020-T2/AMB-19836.info:eu-repo/semantics/publishedVersio

Prospective, randomized trial comparing fluids and dobutamine optimization of oxygen delivery in high-risk surgical patients [ISRCTN42445141]

INTRODUCTION: Preventing perioperative tissue oxygen debt contributes to a better postoperative recovery. Whether the beneficial effects of fluids and inotropes during optimization of the oxygen delivery index (DO(2)I) in high-risk patients submitted to major surgeries are due to fluids, to inotropes, or to the combination of the two is not known. We aimed to investigate the effect of DO(2)I optimization with fluids or with fluids and dobutamine on the 60-day hospital mortality and incidence of complications. METHODS: A randomized and controlled trial was performed in 50 high-risk patients (elderly with coexistent pathologies) undergoing major elective surgery. Therapy consisted of pulmonary artery catheter-guided hemodynamic optimization during the operation and 24 hours postoperatively using either fluids alone (n = 25) or fluids and dobutamine (n = 25), aiming to achieve supranormal values (DO(2)I > 600 ml/minute/m(2)). RESULTS: The cardiovascular depression was an important component in the perioperative period in this group of patients. Cardiovascular complications in the postoperative period occurred significantly more frequently in the volume group (13/25, 52%) than in the dobutamine group (4/25, 16%) (relative risk, 3.25; 95% confidence interval, 1.22–8.60; P < 0.05). The 60-day mortality rates were 28% in the volume group and 8% in the dobutamine group (relative risk, 3.00; 95% confidence interval, 0.67–13.46; not significant). CONCLUSION: In patients with high risk of perioperative death, pulmonary artery catheter-guided hemodynamic optimization using dobutamine determines better outcomes, whereas fluids alone increase the incidence of postoperative complications

Noninvasive ventilation immediately after extubation improves weaning outcome after acute respiratory failure: a randomized controlled trial

Abstract\ud \ud \ud \ud Introduction\ud \ud Noninvasive ventilation (NIV), as a weaning-facilitating strategy in predominantly chronic obstructive pulmonary disease (COPD) mechanically ventilated patients, is associated with reduced ventilator-associated pneumonia, total duration of mechanical ventilation, length of intensive care unit (ICU) and hospital stay, and mortality. However, this benefit after planned extubation in patients with acute respiratory failure of various etiologies remains to be elucidated. The aim of this study was to determine the efficacy of NIV applied immediately after planned extubation in contrast to oxygen mask (OM) in patients with acute respiratory failure (ARF).\ud \ud \ud \ud Methods\ud \ud A randomized, prospective, controlled, unblinded clinical study in a single center of a 24-bed adult general ICU in a university hospital was carried out in a 12-month period. Included patients met extubation criteria with at least 72 hours of mechanical ventilation due to acute respiratory failure, after following the ICU weaning protocol. Patients were randomized immediately before elective extubation, being randomly allocated to one of the study groups: NIV or OM. We compared both groups regarding gas exchange 15 minutes, 2 hours, and 24 hours after extubation, reintubation rate after 48 hours, duration of mechanical ventilation, ICU length of stay, and hospital mortality.\ud \ud \ud \ud Results\ud \ud Forty patients were randomized to receive NIV (20 patients) or OM (20 patients) after the following extubation criteria were met: pressure support (PSV) of 7 cm H2O, positive end-expiratory pressure (PEEP) of 5 cm H2O, oxygen inspiratory fraction (FiO2) ≤ 40%, arterial oxygen saturation (SaO2) ≥ 90%, and ratio of respiratory rate and tidal volume in liters (f/TV) < 105. Comparing the 20 patients (NIV) with the 18 patients (OM) that finished the study 48 hours after extubation, the rate of reintubation in NIV group was 5% and 39% in OM group (P = 0.016). Relative risk for reintubation was 0.13 (CI = 0.017 to 0.946). Absolute risk reduction for reintubation showed a decrease of 33.9%, and analysis of the number needed to treat was three. No difference was found in the length of ICU stay (P = 0.681). Hospital mortality was zero in NIV group and 22.2% in OM group (P = 0.041).\ud \ud \ud \ud Conclusions\ud \ud In this study population, NIV prevented 48 hours reintubation if applied immediately after elective extubation in patients with more than 3 days of ARF when compared with the OM group.\ud \ud \ud \ud Trial Registration number\ud \ud ISRCTN: 41524441.We thank all the physicians, physiotherapists, and nurses that took care of the patients throughout the protocol, the statisticians for the statistical analyses, and Adriana Pardini for revision of the language. This study was supported by Division of Critical Care, Hospital de Base de São José do Rio Preto, Rio Preto, SP, Brazil, and Division of Pulmonary and Critical Care Hospital das Clínicas of São Paulo Medical School, University of São Paulo, São Paulo, Brazil

Expressão gênica induzida por estresses abióticos em nódulos de feijão-caupi

O objetivo deste trabalho foi avaliar o efeito isolado ou simultâneo dos estresses hídrico e térmico na expressão gênica em nódulos de feijão-caupi. A bactéria Bradyrhizobium japonicum (estirpe BR 3267) foi inoculada em sementes de feijão-caupi da cultivar IPA 206 e, 35 dias após a germinação, as plantas foram submetidas a diferentes regimes de disponibilidade hídrica e a estresse térmico, em casa de vegetação. Para a identificação dos genes diferencialmente expressos, foi utilizada a técnica de cDNA-AFLP, tendo-se isolado 67 fragmentos derivados de transcritos (FDTs) diferencialmente expressos. Após o sequenciamento dos FDTs e das análises de similaridade, com uso do programa Blastx, foram identificados 14 genes diferencialmente expressos envolvidos em diferentes processos metabólicos. O padrão de expressão de seis genes sob estresse abiótico foi confirmado por RT-qPCR, e observou-se indução de genes pertencentes a diferentes categorias funcionais, como biossíntese de ácido abscísico, sinalização celular, transportador de prolina e biossíntese de lipídeos de membranas. A expressão desses genes indica sua participação em processos relacionados à proteção dos nódulos ao estresse abiótico

Magnetic carbon nanotubes obtained from plastic as catalysts for wet peroxide oxidation of paracetamol

Magnetic carbon nanotubes (MCNTs) were prepared by catalytic chemical vapour deposition (CCVD) and tested as catalysts for catalytic wet peroxide oxidation (CWPO) of paracetamol (PCM). For the synthesis of the MCNTs, low-density polypropylene (LDPE) and high-density polypropylene (HDPE) were used as model carbon precursors present in urban plastic solid waste (Aboul-Enein, 2018). The catalyst employed in CCVD was magnetite supported on alumina prepared by a sol-gel process. The CWPO runs were conducted with the stoichiometric concentration of H2O2 needed for the full mineralization of 100 ppm of PCM, at 80 °C and initial pH 3.5, following experimental methods described elsewhere (Silva, 2019). The catalyst prepared from LDPE, LDPE_MCNTW, was able to completely degrade the pollutant within 6 h of reaction, while HDPE_MCNTW took 8 h to achieve the same removal. Iron measurement in the final reaction solutions showed the absence of possible additional pollution coming from iron leaching of the catalysts.This work was financially supported by project "PLASTIC_TO_FUEL&MAT – Upcycling Waste Plastics into Fuel and Carbon Nanomaterials" (PTDC/EQU-EQU/31439/2017), Base Funding - UIDB/50020/2020 of the Associate Laboratory LSRE-LCM - funded by national funds through FCT/MCTES (PIDDAC), and CIMO (UIDB/00690/2020) through FEDER under Program PT2020. Fernanda F. Roman acknowledges the national funding by FCT, Foundation for Science and Technology, and FSE, European Social Fund, through the individual research grant SFRH/BD/143224/2019.info:eu-repo/semantics/publishedVersio

Selective denitrification of a simulated oily wastewater using Janus-structured carbon nanotubes

Carbon nanotubes (CNTs) bearing a Janus-like structure were synthesized by chemical vapor deposition considering ethylene and acetonitrile as carbon and nitrogen sources. The developed materials were applied as catalyst in the oxidation of 4-nitrophenol (4-NP) dissolved in a biphasic medium (water/2,2,4-trimeylpentane) simulating a contaminated oily wastewater. The CNT prepared using both ethylene and acetonitrile precursors shows a Janus-structure, leading to the highest abatement of 4-NP as well as to the highest removal of TOC, proving to be an alternative towards the removal of lipophilic pollutants from oily effluents, allowing to reclaim the oily phase.This work was financially supported by project "PLASTIC_TO_FUEL&MAT – Upcycling Waste Plastics into Fuel and Carbon Nanomaterials" (PTDC/EQU-EQU/31439/2017), Base Funding - UIDB/50020/2020 of the Associate Laboratory LSRE-LCM - funded by national funds through FCT/MCTES (PIDDAC), and CIMO (UIDB/00690/2020) through FEDER under Program PT2020. F. F. Roman acknowledges the national funding by FCT, Foundation for Science and Technology, and FSE, European Social Fund, through the individual research grant SFRH/BD/143224/2019. A. Santos Silva was supported by the doctoral grant SFRH/BD/151346/2021 financed by FCT with funds from NORTE2020, under MIT Portugal Programinfo:eu-repo/semantics/publishedVersio