301 research outputs found
Photocatalytic processes as a potential solution for plastic waste management
Plastics have become a critical environmental problem due to their widespread use, high physico-chemical stability and the inefficiency of wastewater treatments. Despite the efforts to reduce production and to increase reuse and recycling, the current strategies for plastic waste treatment are not suitable to handle with the growing demand of plastics and the concomitant waste in an environmentally friendly manner.
Herein, we review the existing strategies for the treatment of plastic waste, highlighting photocatalytic processes as a potential solution for the degradation of plastics. The possibility of incorporating photocatalysts to plastics during the production process could enhance their light-activated biodegradability. Parallelly, photocatalysts can be employed during waste treatment processes of non-biodegradable stable plastics. The scarcely studied factors affecting plastic photocatalytic degradation, namely catalyst type, reactor configuration, and radiation source (intensity and wavelength), are discussed, highlighting the role that photocatalytic processes can play in the future of plastic management. Finally, relevant quantification methods for measuring the photo-degradation of plastics are overviewed.
We believe that photocatalysis can be an environmentally friendly strategy both to increase the biodegradability of plastics and to treat plastic waste. With this novel comprehensive overview, we hope to stimulate further research and innovation in this field.Xunta de Galicia | Ref. ED481B 2019/091Universidade de Vigo/CISU
Biovalorization of Brewery Waste by Applying Anaerobic Digestion
In the food industry, the brewing sector holds a strategic economic position: in the year 2013, the beer production of the EU-28 was equal to 383,553,000 hL. The brewing process includes chemical and biochemical reactions and solid-liquid separations, involving the generation of various residues and by-products, among which the major two fractions are brewer’s spent grain (BSG), and exhausted brewery yeast (BY). Although until today their main use has been for animal feed, in recent years, several studies have investigated the application of anaerobic digestion in order to revalue the brewery wastes.
In this work, specific methane production (SMP) and first-order solubilisation (disintegration+ hydrolysis) rates (ksol) for BSG and BY were evaluated. Biomethanation tests were performed in 5-L fed-batch stirred reactors at several substrate/inoculum ratios. The obtained SMP ranged from 0.255 L CH4 g–1 COD for exhausted brewery yeast to 0.284 L CH4 g–1 COD for brewer’s spent grain. The estimated ksol values ranged from 0.224 d–1 for BSG to 0.659 d–1 for BY
Air conditioning production by a single effect absorption cooling machine directly coupled to a solar collector field. Application to Spanish climates
Due to the increasing energy consumption of air conditioning in buildings and the need to decrease the fossil CO2 emissions to the
environment, the interest of using renewable energy sources shows up stronger than ever.
We present a general study whose aim is to propose a method to evaluate an upper bound in the potential of solar cooling by using some
simplified models. As an example it has been applied to the very diverse climates of Spain. In the paper it has been assumed a direct solar
coupling between the solar collector field and a single effect absorption cooling machine, without any intermediate solar storage tank. An
equation is obtained that shows the dependence of the generator/solar-collectors equilibrium temperature on basic design parameters of the
system (absorption machine-solar collectors). The paper analyzes the effect of these on the total amount of cooling produced along a typical
mean year and the peak cooling power. The paper also includes a discussion on how to estimate the values and what is their physical meaning
of the parameters which define the behavior of real absorption machines.
Finally tables are included for the 12 climates of Spain that can be used as an example of how to make a quick pre-sizing of such direct
coupled system. The classification of the Spanish climates is based on general data (average monthly total horizontal solar radiation, average
monthly dry temperature, etc.) and the results could be generalized for climates with the same severity. Moreover if hourly weather data
is available for any place (like tmy2, bin, epw, etc. files), the procedure can be applied without further changes.Sarabia Escrivà, EJ.; Lamas Sivila, EV.; Soto Francés, VM. (2011). Air conditioning production by a single effect absorption cooling machine directly coupled to a solar collector field. Application to Spanish climates. Solar Energy. 85(9):2108-2121. doi:10.1016/j.solener.2011.05.019S2108212185
GO-TiO2 as a highly performant photocatalyst maximized by proper parameters selection
The synthesis and characterization of novel graphene oxide coupled to TiO2 (GO-TiO2) was carried out in order to better understand the performance of this photocatalyst, when compared to well-known TiO2 (P25) from Degussa. Thus, its physical-chemical characterization (FTIR, XRD, N2 isotherms and electrochemical measurements) describes high porosity, suitable charge and high electron mobility, which enhance pollutant degradation. In addition, the importance of the reactor set up was highlighted, testing the effect of both the irradiated area and distance between lamp and bulb solution. Under optimal conditions, the model drug methylthioninium chloride (MC) was degraded and several parameters were assessed, such as the water matrix and the catalyst reutilization, a possibility given the addition of H2O2. The results in terms of energy consumption compete with those attained for the treatment of this model pollutant, opening a path for further research.Xunta de Galicia | Ref. ED481B 2019/091Ministerio de Ciencia e Innovación | Ref. PID2020-113667GB-I0
Fluoride-doped TiO2 photocatalyst with enhanced activity for stable pollutant degradation
Fluoride-doped TiO2 (F-TiO2) was synthesized by an efficient and simple one-step synthesis and successfully used for the UV-photo-degradation of the toxic and stable pollutants methylene blue (MB) and bisphenol A (BPA). Initially, the synthesized catalyst was characterized and compared to untreated TiO2 (P25 Degussa) by different physical–chemical analyses such as XRD, band gap calculation, SEM, EDS, FITR, ECSA, or EIS. F-TiO2 defeated commercial TiO2, and almost complete pollutant removal was achieved within 30 min. The energy consumption was reduced as a result of the suitable reactor set-up, which reduced light scattering, and by the application of a long-pulse radiation procedure, where the lamp was switched off during periods where the radical degradation continued. This enhanced the overall photocatalysis process performance. Under these conditions, 80% of MB removal was attained within 15 min radiation with an energy consumption of only 0.070 Wh min−1, demonstrating a much better efficiency when compared to previously reported data. The catalyst was reusable, and its performance can be improved by the addition of H2O2. The results were validated by BPA degradation and the treatment of real wastewaters with both pollutants. The results were so encouraging that a scale-up reactor has been proposed for future studies.Xunta de Galicia | Ref. ED481B 2019/091Xunta de Galicia | Ref. ED431C 2021-43Ministerio de Ciencia e Innovación | Ref. PCI2022-132941Ministerio de Ciencia e Innovación | Ref. PID2020- 113667GB-I0
Structured organic frameworks as endocrine disruptor adsorbents suitable for Fenton regeneration and reuse
New porous materials, such as metal-organic frameworks (MOFs) and covalent-organic frameworks (COFs), have been actively investigated due to their environmental applications. In this study, four of such structured materials, namely Fe3O4 @COF, MIL-53(Al), MIL-53(Al)-F127 and NH2-MIL-101(Fe) were synthetized. These materials have been tested for the first time for the adsorption in aqueous media of two endocrine disruptor pollutants, bisphenol A (BPA) and prednisolone (PDN). The adsorbents were characterized by the analysis of the
point of zero charge (PZC), the functional groups (FTIR) and their physic-chemical structure (N2-isotherms, SEM, XRD and XPS). MIL-53-Al provided the highest uptake of both BPA (177.78 mg g− 1) and PDN (280.70 mg g− 1) even when using a real wastewater matrix. Additionally, this MOF resulted to be a so-called catalytic-adsorbent, maintaining an appropriate adsorbent capacity after five regenerations cycles via Fenton-like process, causing only 20% and 5% adsorption detriment for BPA and PDN, respectively. This avoids spent adsorbent disposal
issues and make this new kind of adsorbent to have the potential to be used in real environmental application scenarios.Agencia Estatal de Investigación | Ref. PID2020-113667GB-I00Agencia Estatal de Investigación | Ref. PDC2021-121394-I00Xunta de Galicia | Ref. ED481D-2023/015Universidade de Vigo/CISU
On the behavior of CTAB/CTAOH adlayers on gold single crystal surfaces
The behavior of adsorbed CTAB and CTAOH on gold single crystal electrodes has been studied in solutions with different pH values. For the different single crystal electrodes, the adsorbed adlayer formed by CTA+ cations is in contact with the surface, when the electrode charge is negative. As the surface charge becomes positive, the adlayer detaches from the surface and water molecules permeate through it, giving rise to characteristic peaks in the voltammogram. Charge and laser induced jump temperature measurements show that the composition of the adlayer contains not only the CTA+ cations but also anions, which are required to stabilize the adlayer. In alkaline solutions, the higher solubility of CTAB/CTAOH in alkaline solutions leads to the partial desorption of the adlayer when these species are not present in the solution. When CTAB or CTAOH are dissolved in the alkaline cell solution, the adlayer is strongly bonded to the surface in the whole potential window due to the negative charge of the surface.Financial support from Ministerio de Ciencia e Innovación (Project PID2019-105653GB-I00) and Generalitat Valenciana (Project PROMETEO/2020/063) is acknowledged
Utilidad diagnóstica de los marcadores de estrés oxidativo en artritis reumatoide precoz en pacientes no fumadores y anti-CCP negativos
Fundamento. A pesar del desarrollo de nuevos marcadores y cri- terios diagnósticos para la artritis reumatoide (AR), todavía mu- chos pacientes son diagnosticados tras varios años de síntomas. Los marcadores de estrés oxidativo se incrementan ya en una fase temprana de la enfermedad. El objetivo del presente estudio fue evaluar el valor diagnóstico adicional de estos marcadores.
Método. Se realizó un estudio de casos y controles. Los pacien- tes reclutados para el estudio cumplían los criterios para AR de la ACR 1987, todos ellos tenían menos de 2 años de síntomas y sin tratamiento previo con fármacos modificadores de la enfer- medad antirreumática (DMARD), esteroides o vitamina E. Los controles fueron seleccionados de los familiares del paciente y pareados (1:1) por sexo, edad, hábito tabáquico actual. Los marcadores de daño oxidativo que se midieron fueron malo- nildialdehído (MDA), hidroperóxidos lipídicos (LOOH) y pro- teínas carboniladas (CP). El Análisis estadístico se realizó de acuerdo con la STARD.
resultados. Se incluyeron sesenta y cinco pacientes con AR sin tratamiento y 65 controles sanos. LOOH, CP, los anticuerpos con péctidos citrulinados (anti-CCP) y el factor reumatoide (FR) fueron significativamente mayores en los pacientes, y MDA fue mayor en los controles. Los mismos resultados se obtuvieron en los subgrupos de pacientes que fuman o no, y en anti-CCP positivos o negativos. El valor diagnóstico de los marcadores tradicionales mostró una buena especificidad pero una baja sensibilidad. La construcción de los modelos logísti- cos con la adicción de LOOH y CP aumenta la sensibilidad y el área bajo la curva ROC, especialmente en los no fumadores (66%) y los pacientes negativos ante-CCP (51%).
conclusiones. Al incorporar LOOH o CP a los marcadores de la enfermedad tradicionales en AR, bien por separado o ambos conjuntamente, mejoró el diagnóstico de AR, especialmente en los pacientes no fumadores o aquellos con anticuerpos anti- CCP negativos.background. Besides the development of new markers and di- agnostic criteria for rheumatoid arthritis (RA), many patients are still diagnosed after several years of symptoms. Oxidative stress markers are already increased at an early stage of RA. Our aim was to evaluate the additional diagnostic value of these markers.
Methods. A case-control study was performed. Patients met the 1987 RA ACR criteria, less than 2 years of symptoms and no previous treatment with disease-modifying anti-rheumatic drugs (DMARD), steroids or vitamin E. Controls were select- ed from patient’s relatives and matched (1:1) by gender, age, and current smoking habit. Oxidative damage markers were malonyldialdehyde (MDA), Lipid hydroperoxides (LOOH) and Carbonyl proteins (CP). Statistical analysis was performed in agreement with the STARD initiative.
results. Sixty-five RA patients without treatment and 65 healthy controls were included. LOOH, CP, antibodies against citrullinated peptides (anti-CCP) and rheumatoid factor (RF) were significantly higher in patients, and MDA higher in con- trols. The same results were obtained in the subgroups of pa- tients who smoke or not, and in anti-CCP positive or negative. The diagnosis performance of traditional markers showed good specificity but low sensitivity. The addition of LOOH and CP increased the sensitivity and the area under the receiving operating characteristic (ROC) curve especially in non-smok- ing (66%) and negative anti-CCP (51%) patients.
conclusions. The separate or combined addition of LOOH or CP to the traditional disease markers improved the diag- nosis of RA, especially in non-smoking or negative anti-CCP patients
The Lamé Class of Lorenz Curves.
In this paper, the class of Lamé Lorenz curves is studied. This family has the advantage of modeling inequality with a single parameter. The family has a double motivation: it can be obtain from an economic model and from simple transformations of classical Lorenz curves. The underlying cumulative distribution functions have a simple closed form, and correspond to the Singh-Maddala and Dagum distributions, which are well known in the economic literature. The Lorenz order is studied and several inequality and polarization measures are obtained, including Gini, Donaldson-Weymark-Kakwani, Pietra and Wolfson indices. Some extensions of the Lamé family are obtained. Fitting and estimation methods under two different data configuration are proposed. Empirical applications with real data are given. Finally, some relationships with other curves are included.The authors thank to Ministerio de Econom a y Competitividad, project
ECO2010-15455, for partial support. The second author thanks to the Ministerio
de Educaci on (FPU AP-2010-4907) for partial support. We are grateful
for the constructive suggestions provided by the reviewers, which improved
the paper
Professional practice environment in Nursing
Un entorno de práctica profesional en enfermería (EPPE) es el que promueve, facilita u obstaculiza al personal de enfermería para prestar cuidados de calidad, además de incrementar la seguridad y bienestar de los pacientes y de sus profesionales. Construir entornos positivos fomenta la excelencia de la organización, optimiza los resultados y mejora la percepción y satisfacción del usuario. En numerosos países se ha podido constatar que determinados ámbitos asistenciales de enfermería considerados excelentes influyen de forma objetiva en los resultados en salud, con disminución de la morbimortalidad, aumento de la calidad y mejora del cuidado (1), además de la contención de costes (2) y otros múltiples beneficios para la sociedad, el ciudadano, el usuario y el profesional
- …