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1.
Angew Chem Int Ed Engl ; 62(36): e202301909, 2023 Sep 04.
Artículo en Inglés | MEDLINE | ID: mdl-37162030

RESUMEN

Photocatalytic biomass conversion into high-value chemicals and fuels is considered one of the hottest ongoing research and industrial topics toward sustainable development. In short, this process can cleave Cß -O/Cα -Cß bonds in lignin to aromatic platform chemicals, and further conversion of the polysaccharides to other platform chemicals and H2 . From the chemistry point of view, the optimization of the unique cooperative interplay of radical oxidation species (which are activated via molecular oxygen species, ROSs) and substrate-derived radical intermediates by appropriate control of their type and/or yield is key to the selective production of desired products. Technically, several challenges have been raised that face successful real-world applications. This review aims to discuss the recently reported mechanistic pathways toward selective biomass conversion through the optimization of ROSs behavior and materials/system design. On top of that, through a SWOT analysis, we critically discussed this technology from both chemistry and technological viewpoints to help the scientists and engineers bridge the gap between lab-scale and large-scale production.

2.
J Appl Microbiol ; 133(5): 2877-2892, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-35892194

RESUMEN

Rising global populations have amplified food scarcity across the world and ushered in the development of genetically modified (GM) crops to overcome these challenges. Cultivation of major crops such as corn and soy has favoured GM crops over conventional varieties to meet crop production and resilience needs. Modern GM crops containing small interference RNA molecules and antibiotic resistance genes have become increasingly common in the United States. However, the use of these crops remains controversial due to the uncertainty regarding the unintended release of its genetic material into the environment and possible downstream effects on human and environmental health. DNA or RNA transgenes may be exuded from crop tissues during cultivation or released during plant decomposition and adsorbed by soil. This can contribute to the persistence and bioavailability in soil or water environment and possible uptake by soil microbial communities and further passing of this information to neighbouring bacteria, disrupting microbial ecosystem services such as nutrient cycling and soil fertility. In this review, transgene mechanisms of action, uses in crops, and knowledge regarding their environmental fate and impact to microbes are evaluated. This aims to encapsulate the current knowledge and promote further research regarding unintended effects transgenes may cause.


Asunto(s)
Productos Agrícolas , Ecosistema , Estados Unidos , Humanos , Productos Agrícolas/genética , Plantas Modificadas Genéticamente/genética , Antibacterianos/farmacología , Farmacorresistencia Microbiana/genética , ARN , Suelo , Agua/farmacología
3.
Prev Med ; 153: 106860, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34687733

RESUMEN

Despite demonstrated efficacy of vaccines against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the causative agent of coronavirus disease-2019 (COVID-19), widespread hesitancy to vaccination persists. Improved knowledge regarding frequency, severity, and duration of vaccine-associated symptoms may help reduce hesitancy. In this prospective observational study, we studied 1032 healthcare workers who received both doses of the Pfizer-BioNTech SARS-CoV-2 mRNA vaccine and completed post-vaccine symptom surveys both after dose 1 and after dose 2. We defined appreciable post-vaccine symptoms as those of at least moderate severity and lasting at least 2 days. We found that symptoms were more frequent following the second vaccine dose than the first (74% vs. 60%, P < 0.001), with >80% of all symptoms resolving within 2 days. The most common symptom was injection site pain, followed by fatigue and malaise. Overall, 20% of participants experienced appreciable symptoms after dose 1 and 30% after dose 2. In multivariable analyses, female sex was associated with greater odds of appreciable symptoms after both dose 1 (OR, 95% CI 1.73, 1.19-2.51) and dose 2 (1.76, 1.28-2.42). Prior COVID-19 was also associated with appreciable symptoms following dose 1, while younger age and history of hypertension were associated with appreciable symptoms after dose 2. We conclude that most post-vaccine symptoms are reportedly mild and last <2 days. Appreciable post-vaccine symptoms are associated with female sex, prior COVID-19, younger age, and hypertension. This information can aid clinicians in advising patients on the safety and expected symptomatology associated with vaccination.


Asunto(s)
COVID-19 , SARS-CoV-2 , Vacunas contra la COVID-19 , Femenino , Humanos , ARN Mensajero , Vacunación
4.
J Environ Manage ; 275: 111198, 2020 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-32836168

RESUMEN

The disposal of landfill leachate is a chronic problem facing the municipal solid waste industry. The composition of landfill leachate is highly variable and often dependent on site-specific conditions. Due to the potentially disruptive impact on wastewater treatment processes, wastewater treatment plants (WWTP) are reluctant to accept landfill leachate for co-treatment. To improve the ability of WWTPs to screen the impact of landfill leachate and reduce landfill owners' cost of disposal, two bench scale methods were evaluated. First, six landfill leachates were screened with the specific oxygen uptake rate (SOUR) test, and second, the effect of leachate on the efficacy of activated sludge processes using lab scale sequencing batch reactors (SBRs) was determined with volumetric loading rates ranging from 5% to 20%. Results suggested that these tools can be used to estimate the impacts of leachate loading on biological processes. Both tools were able to identify loadings where biological activity was increased and inhibition of biological processes was minimized. The loading that maximized microbial activity was leachate specific and typically ranged from 5% to 10%. Taken together, these results suggest that improved landfill leachate screening and testing may improve outcomes at WWTPs by identifying a "Goldilocks" loading rate that increases biological activity. Nevertheless, our results also demonstrated that the effluent quality was degraded even at loading rates that increased biological activity. It is uncertain at this time if biological acclimation can remedy increased effluent nutrient mass loadings, suggesting further research is needed.


Asunto(s)
Aguas Residuales , Contaminantes Químicos del Agua , Reactores Biológicos , Nitrógeno/análisis , Nutrientes , Aguas del Alcantarillado , Contaminantes Químicos del Agua/análisis
5.
J Biol Chem ; 292(44): 18129-18144, 2017 11 03.
Artículo en Inglés | MEDLINE | ID: mdl-28893905

RESUMEN

Lysine acetylation is a widespread posttranslational modification affecting many biological pathways. Recent studies indicate that acetylated lysine residues mainly exhibit low acetylation occupancy, but challenges in sample preparation and analysis make it difficult to confidently assign these numbers, limiting understanding of their biological significance. Here, we tested three common sample preparation methods to determine their suitability for assessing acetylation stoichiometry in three human cell lines, identifying the acetylation occupancy in more than 1,300 proteins from each cell line. The stoichiometric analysis in combination with quantitative proteomics also enabled us to explore their functional roles. We found that higher abundance of the deacetylase sirtuin 1 (SIRT1) correlated with lower acetylation occupancy and lower levels of ribosomal proteins, including those involved in ribosome biogenesis and rRNA processing. Treatment with the SIRT1 inhibitor EX-527 confirmed SIRT1's role in the regulation of pre-rRNA synthesis and processing. Specifically, proteins involved in pre-rRNA transcription, including subunits of the polymerase I and SL1 complexes and the RNA polymerase I-specific transcription initiation factor RRN3, were up-regulated after SIRT1 inhibition. Moreover, many protein effectors and regulators of pre-rRNA processing needed for rRNA maturation were also up-regulated after EX-527 treatment with the outcome that pre-rRNA and 28S rRNA levels also increased. More generally, we found that SIRT1 inhibition down-regulates metabolic pathways, including glycolysis and pyruvate metabolism. Together, these results provide the largest data set thus far of lysine acetylation stoichiometry (available via ProteomeXchange with identifier PXD005903) and set the stage for further biological investigations of this central posttranslational modification.


Asunto(s)
Regulación de la Expresión Génica , Lisina/metabolismo , Procesamiento Proteico-Postraduccional , Precursores del ARN/metabolismo , Procesamiento Postranscripcional del ARN , ARN Ribosómico/metabolismo , Sirtuina 1/metabolismo , Acetilación/efectos de los fármacos , Métodos Analíticos de la Preparación de la Muestra , Carbazoles/farmacología , Línea Celular Transformada , Línea Celular Tumoral , Cromatografía Líquida de Alta Presión , Perfilación de la Expresión Génica , Regulación de la Expresión Génica/efectos de los fármacos , Inhibidores de Histona Desacetilasas/farmacología , Humanos , Cinética , Mapeo Peptídico , Procesamiento Proteico-Postraduccional/efectos de los fármacos , Proteómica/métodos , Procesamiento Postranscripcional del ARN/efectos de los fármacos , ARN Ribosómico 28S/metabolismo , Proteínas Ribosómicas/genética , Proteínas Ribosómicas/metabolismo , Sirtuina 1/antagonistas & inhibidores , Sirtuina 1/genética , Espectrometría de Masas en Tándem
6.
Ethn Dis ; 28(Suppl 2): 457-466, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30202199

RESUMEN

Objective: To develop an intervention to improve the mental health referral and care process for children referred by primary care providers (PCPs) to community mental health clinics (MHCs) using a community partnered approach. Design: A Project Working Group (PWG) with representatives from each partner organization met monthly for 6 months. Setting: Multi-site federally qualified health center (FQHC) and two community MHCs in Los Angeles county. Participants: 26 stakeholders (14 FQHC clinic providers/staff, 8 MHC providers/staff, 4 parents) comprised the PWG. Data Sources: Qualitative interviews, PWG meeting notes, intervention processes and workflow reports. Intervention: The PWG reviewed qualitative data from stakeholders (interviews of 7 parents and 13 providers/staff). The PWG met monthly to identify key transition points where access to and coordination of care were likely compromised and to develop solutions. Results: Three critical transition points and system solutions were identified: 1) Parents refuse initial referral to the MHC due to stigma regarding mental health services. Solution: During initial referral, parents watch a video introducing them to the MHC. 2) Parents don't complete the MHC's screening after referral. Solution: A live videoconference session connecting parents at the FQHC with MHC staff ensures completion of the screening and eligibility process. 3) PCPs reject transfer of patients back to primary care for ongoing psychotropic medication management. Solution: Regularly scheduled live videoconferences connect PCPs and MHC providers. Conclusions: A community partnered approach to care design utilizing telehealth for care coordination between clinics can potentially be used to address key challenges in MHC access for children.


Asunto(s)
Accesibilidad a los Servicios de Salud/organización & administración , Colaboración Intersectorial , Servicios de Salud Mental/organización & administración , Atención Primaria de Salud/métodos , Telemedicina , Niño , Centros Comunitarios de Salud/organización & administración , Femenino , Personal de Salud , Humanos , Masculino , Salud Mental/tendencias , Padres , Derivación y Consulta/organización & administración , Participación de los Interesados , Telemedicina/métodos , Telemedicina/organización & administración
7.
Langmuir ; 31(13): 3952-7, 2015 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-25751745

RESUMEN

Monodisperse Pd2Sn nanorods with tuned size and aspect ratio were prepared by co-reduction of metal salts in the presence of trioctylphosphine, amine, and chloride ions. Asymmetric Pd2Sn nanostructures were achieved by the selective desorption of a surfactant mediated by chlorine ions. A preliminary evaluation of the geometry influence on catalytic properties evidenced Pd2Sn nanorods to have improved catalytic performance. In view of these results, Pd2Sn nanorods were also evaluated for water denitration.

8.
Aten Primaria ; 47(9): 581-8, 2015 Nov.
Artículo en Español | MEDLINE | ID: mdl-25835344

RESUMEN

OBJECTIVE: To determine the prevalence of COPD and smoking in a Health District, to correlate real, registered, and extrapolated morbidity. To determine personal, family and social profiles. To determine the validity of the lung function questionnaire. DESIGN: Prevalence study. LOCATION: Urban District Health. PARTICIPANTS: Random selection of 233 people aged 40-75years. MAIN MEASUREMENTS: Age, sex, pack/years, spirometry, pulse-oximetry, medication, income. TESTS: Fagerström, Richmond, MOS, APGAR, and lung function. RESULTS: Mean age was 53.7+7.6years, with 57.9% women. Registered morbidity for COPD 1.2% (0.5-3.9%). Prevalence 4.7% (1.5% female, 9.2% male), extrapolated prevalence: 10.2%. Registered morbidity for Smoking 10.7% (1-19.4%); prevalence: 18.5% (20% female, 16.3% male), extrapolated prevalence 23.95%. Lung function questionnaire: positive likelihood ratio 3.18; negative 0.1. High probability of COPD (59.5%) in >30 packs/year smokers. Smokers consume a mean of 20.8 packs/year. Women showed higher physical dependence (36% versus 21%). More probability of achieving successful smoking cessation in men (57.1% versus 44%). There was 14.7% perceived family dysfunction; 6.9% have a low global index of social support, and 9.1% in COPD subjects. More than two-thirds (70%) of COPD patients had never been hospitalized. There were 10% polymedicated patients compared to 60% in identified COPDs. CONCLUSIONS: Prevalence of COPD and smoking (indicator of avoidable morbidity attributable to primary care) are substantially lower than the reference data. The lung function questionnaire is valid. There was evidence of inter-professional variability. Women smoke more, are more dependent and are less motivated to quit. Their family and social perception is worse. These investigations are essentials for community intervention and operational planning.


Asunto(s)
Medicina Familiar y Comunitaria , Enfermedad Pulmonar Obstructiva Crónica/epidemiología , Fumar/epidemiología , Adulto , Anciano , Estudios Transversales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Prevalencia , Factores de Riesgo , Espirometría , Población Urbana
9.
J Med Entomol ; 2024 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-38941237

RESUMEN

Predicting the potential distribution and coexistence of suitable geographic areas for Chagas disease vectors in the Americas is a crucial task for understanding the eco-epidemiological dynamics of this disease. The potential distribution and coexistence of 3 species-Rhodnius prolixus (Hemiptera: Reduviidae), Cavernicola pilosa (Hemiptera: Reduviidae), and Rhodnius pictipes (Hemiptera: Reduviidae) were modeled. Presence records were obtained and environmental variables were selected based on correlation analysis, Jackknife analysis and knowledge of the biology and natural history of the species. The MaxEnt algorithm included in the kuenm package of R software was used for modeling the potential distribution, and various scenarios of the BAM diagram (Biotic, Abiotic, and Movement variables) were evaluated. The variables contributing to the final models were different for each species. Rhodnius pictipes showed a potential distribution in South America, particularly in Brazil, Bolivia, Peru, Colombia, Venezuela, Guyana, and Suriname. Areas with environmentally suitable conditions for R. prolixus were located in southern Brazil, Peru, Colombia, southern Mexico, Guatemala, El Salvador, and Honduras, whereas for C. pilosa they were in southeastern Brazil, southeastern Central America, Peru, Ecuador, Colombia, Venezuela, Guyana, Suriname, and French Guiana. Co-occurrence analysis revealed distinct patterns in the neotropical region, with some areas indicating the potential distribution of 1 or more species. In Brazil, occurrence and co-occurrence areas were concentrated in the northwest and southeast regions. Overall, this study provides valuable information on the potential distribution and coexistence of vectors, which can inform targeted vector control strategies and contribute to global efforts in combating Chagas disease.

10.
Ultrason Sonochem ; 99: 106550, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37562345

RESUMEN

To solve low mass transfer in photocatalytic technology for water treatment, the combination of photoactive nanoparticles with highly adsorptive materials has been regarded as a successful approach. The optimization of photoactive particle coating in terms of dispersion on the surface of adsorbing support is the main key to reach a maximum synergism for pollutants removal. This study discusses the coating of as-prepared biomass based activated carbon by g-C3N4 using three routes, namely ball milling (AC-CN@BM), physical stirring (AC-CN@Phy) and ultrasonic assisted coating (AC-CN@US). The coating mechanisms by different processes were discussed using different characterization techniques. Ball milling based coating provides good g-C3N4 dispersion on the surface of AC, however, a partial degradation of g-C3N4 structure and a lower surface area were confirmed by FTIR, XRD and BET analysis. Physically designed sample shows a significant agglomeration of particles on the surface of AC. However, ultrasonic coating provides excellent distribution of g-C3N4 and high surface of the composite. In terms of photoactivity, AC-CN@BM exhibits the lowest adsorption and photocatalytic activity under solar light for the removal of ciprofloxacin. AC-CN@Phy showed medium performance, but less physical stability of g-C3N4 particles on AC, leading to their partial release. AC-CN@US showed the highest efficiency and stability after using; suggesting the good combination between g-C3N4 and AC, which in turn maximizes the removal of ciprofloxacin via Adsorb & shuttle process. The overall costs of composite, including the starting elements and the coating ultrasonic process are relatively low and green as compared to commonly reported routes.

11.
Bioresour Technol ; 368: 128333, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36403911

RESUMEN

The production of high-value products from lignocellulosic biomass is carried out through the selective scission of crosslinked CC/CO bonds. Nowadays, several techniques are applied to optimize biomass conversion into desired products with high yields. Photocatalytic technology has been proven to be a valuable tool for valorizing biomass at mild conditions. The photoproduced reactive oxygen species (ROSs) can initiate the scission of crosslinked bonds and form radical intermediates. However, the low mass transfer of the photocatalytic process could limit the production of a high yield of products. The incorporation of ultrasonic cavitation in the photocatalytic system provides an exceptional condition to boost the fragmentation and transformation of biomass into the desired products within a lesser reaction time. This review critically discusses the main factors governing the application of photocatalysis for biomass valorization and tricks to boost the selectivity for enhancing the yield of desired products. Synergistic effects obtained through the combination of sonolysis and photocatalysis were discussed in depth. Under ultrasonic vibration, hot spots could be produced on the surface of the photocatalysts, improving the mass transfer through the jet phenomenon. In addition, shock waves can assist the dissolution and mixing of biomass particles.


Asunto(s)
Ondas Ultrasónicas , Ultrasonido , Especies Reactivas de Oxígeno , Biomasa
12.
Environ Sci Pollut Res Int ; 30(30): 74544-74574, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37227629

RESUMEN

An exponential rise in global pollution and industrialization has led to significant economic and environmental problems due to the insufficient application of green technology for the chemical industry and energy production. Nowadays, the scientific and environmental/industrial communities push to apply new sustainable ways and/or materials for energy/environmental applications through the so-called circular (bio)economy. One of today's hottest topics is primarily valorizing available lignocellulosic biomass wastes into valuable materials for energy or environmentally related applications. This review aims to discuss, from both the chemistry and mechanistic points of view, the recent finding reported on the valorization of biomass wastes into valuable carbon materials. The sorption mechanisms using carbon materials prepared from biomass wastes by emphasizing the relationship between the synthesis route or/and surface modification and the retention performance were discussed towards the removal of organic and heavy metal pollutants from water or air (NOx, CO2, VOCs, SO2, and Hg0). Photocatalytic nanoparticle-coated biomass-based carbon materials have proved to be successful composites for water remediation. The review discusses and simplifies the most raised interfacial, photonic, and physical mechanisms that might take place on the surface of these composites under light irradiation. Finally, the review examines the economic benefits and circular bioeconomy and the challenges of transferring this technology to more comprehensive applications.


Asunto(s)
Carbono , Lignina , Adsorción , Biomasa
13.
Sci Total Environ ; 832: 154804, 2022 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-35341856

RESUMEN

The oil sands industry generates large volumes of oil sands process water (OSPW). There is an urgent need for OSPW treatment to reduce process water inventories and to support current reclamation approaches. This study discusses how efficient ozone (O3)-based combined advanced oxidation processes (AOPs), including hydrogen peroxide (H2O2) and UV-C, are at achieving mineralization while reducing the toxicity arising from such organic components as naphthenic acids (NAs) in OSPW. The results showed that the dissolved organic carbon (DOC) removals of 45%, 84%, 84% and 98%, obtained after 90-min treatments with O3, O3/H2O2, UVC/O3 and UVC/O3/H2O2, respectively, at a production rate of 6 g/L·h O3 were considerably higher than at lower O3 production rates. The acute toxicity on Vibrio fischeri was significantly reduced by all the treatments, which explains the high percentages of NA removal (up to 99% as confirmed by UPLC-QTOF-HRMS.) Mineralization (expressed as DOC removal) was highest with UVC/O3/H2O2 at ca. 2 mg C/L in the treated effluent, which means that it could be used as cooling/boiling process water in bitumen upgrading units. However, considering the energy demand of the treatments tested, the treatment using O3/H2O2 was found to be the most realistic for large-scale applications.


Asunto(s)
Ozono , Contaminantes Químicos del Agua , Purificación del Agua , Ácidos Carboxílicos , Peróxido de Hidrógeno , Yacimiento de Petróleo y Gas , Agua , Contaminantes Químicos del Agua/análisis , Purificación del Agua/métodos
14.
Cancer Genomics Proteomics ; 19(2): 241-258, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35181591

RESUMEN

BACKGROUND/AIM: To date, several proteomics studies in cervical cancer (CC) have focused mainly on squamous cervical cancer (SCC). Our study aimed to discover and clarify differences in SCC and CAD that may provide valuable information for the identification of proteins involved in tumor progression, in CC as a whole, or specific for SCC or CAD. MATERIALS AND METHODS: Total protein extracts from 15 individual samples corresponding to 5 different CC tissue types were compared with a non-cancerous control group using bidimensional liquid chromatography-mass spectrometry (2D LC-MS/MS), isobaric tags for relative and absolute quantitation (ITRAQ), principal component analysis (PCA) and gene set enrichment analysis (GSEA). RESULTS: A total of 622 statistically significant different proteins were detected. Exocytosis-related proteins were the most over-represented, accounting for 25% of the identified and quantified proteins. Based on the experimental results, reticulocalbin 3 (RCN3) and Ras-related protein Rab-14 (RAB14) were chosen for further downstream in vitro and vivo analyses. RCN3 was overexpressed in all CC tissues compared to the control and RAB14 was overexpressed in squamous cervical cancer (SCC) compared to invasive cervical adenocarcinoma (CAD). In the tumor xenograft experiment, RAB14 protein expression was positively correlated with increased tumor size. In addition, RCN3-expressing HeLa cells induced a discrete size increment compared to control, at day 47 after inoculation. CONCLUSION: RAB14 and RCN3 are suggested as potential biomarkers and therapeutic targets in the treatment of CC.


Asunto(s)
Proteómica , Neoplasias del Cuello Uterino , Cromatografía Liquida/métodos , Femenino , Células HeLa , Humanos , Proteómica/métodos , Espectrometría de Masas en Tándem/métodos , Neoplasias del Cuello Uterino/genética , Proteínas de Unión al GTP rab/genética
15.
Health Promot Pract ; 12(6): 840-7, 2011 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-21807951

RESUMEN

In this study, the authors examined reactions of Latino adults with limited English proficiency (LEP) to a culturally and linguistically adapted depression fotonovela, titled "Secret Feelings." Fotonovelas are popular health education tools that use posed photographs, text bubbles with simple text, and dramatic narratives to engage audiences and raise their awareness and knowledge about specific health issues. Four focus groups (N = 32) were conducted at an adult school program (e.g., GED classes). Content analysis was used to generate themes from transcripts and memos. "Secret Feelings" was viewed as an entertaining, engaging, and educational tool that helped combat stigma toward depression and its treatments in the Latino community. Despite learning about depression, participants reported they wanted more information about the causes of depression, the process of recovery, and felt that the story did not shift their apprehensions toward antidepressants. The findings suggest that "Secret Feelings" is a promising depression literacy tool for Latinos with LEP that can raise awareness and knowledge about depression and its treatments, reduce stigma toward depression and antidepressant medications, and model appropriate help-seeking behaviors.


Asunto(s)
Depresión/psicología , Grupos Focales , Conocimientos, Actitudes y Práctica en Salud , Hispánicos o Latinos/psicología , Multilingüismo , Fotograbar , Adulto , Competencia Cultural , Depresión/etnología , Femenino , Promoción de la Salud , Humanos , Los Angeles , Masculino , Adulto Joven
16.
Phys Chem Chem Phys ; 12(44): 14673-6, 2010 Nov 28.
Artículo en Inglés | MEDLINE | ID: mdl-20944839

RESUMEN

High mineralization degree of organic compounds can be achieved by a novel environmentally-friendly full heterogeneous Pd-Fe catalytic system, which involves in situ generation of hydrogen peroxide from formic acid and oxygen, and oxidation of organic compounds by Fenton process in a one-pot reaction.

17.
Water Environ Res ; 81(2): 201-5, 2009 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19323292

RESUMEN

Aqueous solutions of two important quaternary ammonium compounds--16-BAC (benzyl-dimethyl-hexadecylammonium-chloride) and 18-BAC (benzyl-dimethyl-stearylammonium-chloride)--were treated by the ozonation and photo-Fenton processes at different ozone doses and hydrogen peroxide concentrations, respectively. During the photo-Fenton experiments, two different types of lamps were used--a UV mercury vapor medium pressure lamp and a xenon lamp, which simulates solar radiation. The total organic carbon removal was monitored to follow the mineralization of the surfactants. According to the experimental results, after 90 minutes of treatment, the photo-Fenton process achieved up to 80% of mineralization when the UV lamp was used. The efficiency of the photo-Fenton with the xenon lamp was lower. The ozonation process reached, at most, 50% mineralization at the used conditions (ozone dose = 7.57 g/h).


Asunto(s)
Peróxido de Hidrógeno , Hierro , Ozono , Compuestos de Amonio Cuaternario/química , Purificación del Agua/métodos , Compuestos de Amonio Cuaternario/efectos de la radiación , Tensoactivos , Rayos Ultravioleta , Eliminación de Residuos Líquidos , Contaminantes Químicos del Agua/química
18.
Sci Total Environ ; 666: 12-21, 2019 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-30784818

RESUMEN

Different Advanced Oxidation Processes (AOPs) such as photocatalysis, Fenton-based processes and ozonation were studied to include one of these technologies within an integrated solution for produced water (PW) polishing. Synthetic PW was prepared adding toluene, xylene, naphthalene, phenol, acetic and malonic acids to a seawater matrix. Despite that in all AOPs studied in this work BTEX and naphthalene were removed, the efficiency (in terms of TOC removal) of each treatment varied largely. Among these techniques, photocatalysis was found to be the less effective for the treatment of PW, as TOC removals lower than 20% were obtained for the best scenario after 4 h treatment. In the contrary, best results were obtained by ozonation combined with H2O2, where all the organic components were removed, including a high percentage of acetic acid, which was not abated by the rest of the AOPs studied. The optimum conditions for ozonation were 4 g h-1 O3 and 1500 mg L-1 H2O2 at pH 10, where after 2 h a 74% of TOC removal was achieved and the acetic acid elimination was 78%. This condition enabled that ozonation process accounted for the lowest electric energy consumption per order of target compound destruction regarding total organic carbon (TOC).

19.
Chem Commun (Camb) ; (33): 3885-7, 2008 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-18726023

RESUMEN

Hydrogen peroxide formation is achieved with remarkable productivity at ambient conditions (25 degrees C and atmospheric pressure) in aqueous medium using a heterogeneous catalytic system; formic acid is decomposed in the presence of a continuous flow of O(2) over Pd/gamma-Al(2)O(3) catalyst leading to the generation of hydrogen peroxide; the addition of a negligible amount of bromide ion improves the selectivity of the reaction.

20.
J Hazard Mater ; 150(3): 790-4, 2008 Feb 11.
Artículo en Inglés | MEDLINE | ID: mdl-17573190

RESUMEN

Sulfamethoxazole (SMX) is a bacteriostatic antibiotic largely used for diverse types of illness. Its widely use in humans and even in animals releases unmetabolized and active metabolites that have a strong potential in terms of effect in organisms. In this work, 200 mg L(-1) solution of sulfamethoxazole was treated by ozonation at different pH. Results showed that ozonation was proved to be an efficient method to degrade sulfamethoxazole. After 15 min of ozonation (corresponding dose=0.4 g of ozone L(-1)), the complete antibiotic abatement was almost achieved with just 10% of mineralization. The biodegradability and toxicity of the ozonation intermediates were also studied. A biodegradability enhancement (increment of BOD(5)/COD ratio) from 0 to 0.28 was observed after 60 min of ozonation. The acute toxicity of the intermediates was followed by the Microtox test and the toxicity profile showed a slight acute toxicity increment in the first stage of ozonation. The pH variation had an important role in the TOC and COD removal, promoting their growth with the increment of alkalinity. The second order kinetic constants for the ozonation of the SMX in an order of magnitude of 10(5) L mol(-1)s(-1) were also determined for pH 5 and 7.


Asunto(s)
Antibacterianos/química , Oxidantes Fotoquímicos/química , Ozono/química , Sulfametoxazol/química , Contaminantes Químicos del Agua/química , Purificación del Agua/métodos , Concentración de Iones de Hidrógeno , Cinética
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