Oxidação fotoquímica UVC/H2O2 de águas residuárias têxteis visando o reuso no beneficiamento têxtil

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Química, Florianópolis, 2017.Os Processos Oxidativos Avançados (POAs) têm-se destacado nos últimos anos como uma tecnologia alternativa ao tratamento de várias matrizes ambientais, dentre elas, as águas residuárias têxteis. Aplicou-se a oxidação fotoquímica (UVC/H2O2) no tratamento de três águas residuárias têxteis reais, previamente tratadas biologicamente, denominadas de ART-A, ART-B e ART-C. Primeiramente, para a oxidação fotoquímica (UVC/H2O2), um estudo cinético foi realizado para determinar as condições operacionais, tais como a dosagem de peróxido de hidrogênio (0 ? 100 mM), pH da solução (3,0; 5,0; 9,0 e pH natural das águas residuárias: 8,1 (ART-A), 7,7 (ART-B) e 8,3 (ART-C)) e temperatura da solução (15, 23, 35 e 50 ºC). A fotólise do peróxido de hidrogênio sob radiação UVC demonstrou ser uma tecnologia eficiente na remoção de cor das três águas residuárias têxteis reais. O processo UVC/H2O2 aplicado à ART-A e ART-B, respectivamente, resultou em uma remoção de cor de 81% e 68% (método Pt-Co), 83% e 72% (DFZ436nm), 88% e 76% (DFZ525nm) e 86% e 69% (DFZ620nm), utilizando 25 mM de H2O2 e 8,3 e 5,5 kJUVC L-1 em 180 min e 120 min, respectivamente. A água residuária têxtil ? C (ART-C) apresentou parâmetros para remoção de cor, tais como, menor tempo/energia para descoloração, temperatura de saída do reator biológico favorável à descoloração e pH da própria água residuária como melhor resultado para a descoloração. Sendo estes de 90 min/4,1 kJUVC L-1; 35 ºC e 8,31 respectivamente. O processo UVC/H2O2 aplicado à ART-C resultou em uma remoção de cor de 92% (método Pt-Co), 94% (DFZ436nm), 96% (DFZ525nm) e 94% (DFZ620nm). Considerando o lançamento das águas residuárias tratadas em corpos receptores, a biodegradabilidade de ART-A e ART-B, foi avaliada a partir do teste Zahn-Wellens, o qual demonstrou um aumento significativo no percentual de carbono biodegradável ao final do foto-tratamento (62% para ART-A e 45% para ART-B). Por outro lado, com o propósito de reúso no beneficiamento têxtil, ART-C foi utilizada como água de banho durante o processo de tingimento do substrato de algodão e as amostras obtidas resultaram em bons indicadores de qualidade quando comparados ao processo padrão. A percentagem máxima de águas residuárias têxteis tratadas por oxidação fotoquímica que podem ser reutilizadas ? a fim de cumprir os critérios de aceitação mais restritivos do mercado têxtil ? foi de 50%.Abstract : The Advanced Oxidation Processes (AOPs) have emerged as an alternative technology to the treatment of many environmental matrices, among them, the textile wastewaters. This work concerns the application of photochemical oxidation (UVC/H2O2) in the treatment of three real textile wastewaters (ART-A, ART-B, and ART-C), which were previously biologically treated. A kinetic study was performed aiming to determine the optimum operating conditions such as, the dosage of hydrogen peroxide (0 - 100 mM), solution pH (3.0, 5.0, 9.0 and natural wastewater pH: 8.1 (ART-A), 7.7 (ART-B), and 8.3 (ART-C)), and solution temperature (15, 23, 35, and 50 °C). The photolysis of hydrogen peroxide under UVC radiation showed to be an efficient decolourization technology. UVC/H2O2 reaction applied to the ART-A and ART-B resulted in a color reduction of 81% and 68% (Pt-Co method), 83% and 72% (DFZ436nm), 88% and 76% (DFZ525nm) and 86% and 69% (DFZ620nm) using 25 mM H2O2 and 8.3 and 5.5 kJUVC L-1 at 180 min and 120 min of reaction, respectively. The textile wastewater - C (ART-C) presented the parameters for decolourization, such as, less time/energy for decolourization, exit temperature of the biological reactor favorable to the decolourization, and pH of the wastewater itself as the best result for a decolourization. Finally, for the purpose of reuse in textile processing, UVC/H2O2 reaction applied to the ART-C resulted in a color reduction of 92% (Pt-Co method), 94% (DFZ436nm), 96% (DFZ525nm) and 94% (DFZ620nm) using 25 mM H2O2 and 4.1 kJUVC L-1 at 90 min of reaction. The biodegradability of the textile wastewaters was evaluated using the Zahn-Wellens test, and it was observed a significant increase in the percentage of biodegradable carbon along the photo-treatment (62% for TWA and 45% for TWB). ART-C was used in the dyeing of the cotton substrate, and was performed in order to evaluate the reuse capacity of photochemical textile wastewaters treated in textile processing. The maximum percentage of textile waste water treated by photochemical oxidation which can be reused with the purpose of the acceptance criteria and restrictive of the textile market - was 50%

Radiocarbon age-offsets in an arctic lake reveal the long-term response of permafrost carbon to climate change

Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Biogeosciences 119 (2014): 1630–1651, doi:10.1002/2014JG002688.Continued warming of the Arctic may cause permafrost to thaw and speed the decomposition of large stores of soil organic carbon (OC), thereby accentuating global warming. However, it is unclear if recent warming has raised the current rates of permafrost OC release to anomalous levels or to what extent soil carbon release is sensitive to climate forcing. Here we use a time series of radiocarbon age-offsets (14C) between the bulk lake sediment and plant macrofossils deposited in an arctic lake as an archive for soil and permafrost OC release over the last 14,500 years. The lake traps and archives OC imported from the watershed and allows us to test whether prior warming events stimulated old carbon release and heightened age-offsets. Today, the age-offset (2 ka; thousand of calibrated years before A.D. 1950) and the depositional rate of ancient OC from the watershed into the lake are relatively low and similar to those during the Younger Dryas cold interval (occurring 12.9–11.7 ka). In contrast, age-offsets were higher (3.0–5.0 ka) when summer air temperatures were warmer than present during the Holocene Thermal Maximum (11.7–9.0 ka) and Bølling-Allerød periods (14.5–12.9 ka). During these warm times, permafrost thaw contributed to ancient OC depositional rates that were ~10 times greater than today. Although permafrost OC was vulnerable to climate warming in the past, we suggest surface soil organic horizons and peat are presently limiting summer thaw and carbon release. As a result, the temperature threshold to trigger widespread permafrost OC release is higher than during previous warming events.National Science Foundation. Grant Number: ARC-09021692015-02-2

• Current Approach

– Piecewise interpolation methods are fast, but only C n for "small " n, n ∈ {0, 1} for surfaces – Efficient trigonometric interpolation methods (using the FFT) are C ∞ but require evenly spaced dat

Congenital right internal mammary artery to portal vein arteriovenous malformation

Neonatal cases of systemic artery to portal venous system arteriovenous malformations (AVMs) can present unique challenges in terms of diagnosis, management, and treatment. Prompt identification of these AVMs is necessary for minimizing long-term sequelae and optimizing prognosis. Our report describes the diagnosis and successful endovascular coil embolization of a congenital right internal mammary artery (IMA) to portal vein AVM in a young infant initially presenting during routine fetal screening with an incidentally discovered congenital thoracic vascular abnormality

The profile of chiropractors managing patients with low back-related leg pain: analyses of 1907 chiropractors from the ACORN practice-based research network

Abstract Background Approximately 60% of people with low back pain also have associated leg pain symptoms. Guidelines for low back pain recommend non-pharmacological approaches, including spinal manipulation - a therapy provided by chiropractors. However, limited empirical data has examined the characteristics of chiropractors managing patients with low back-related leg pain (LBRLP). Our objective is to describe the prevalence, profile and practice characteristics of Australian chiropractors who often treat LBRLP, compared to those who do not often treat LBRLP. Methods This is a cross-sectional analysis of a nationally representative sample from the Australian Chiropractic Research Network (ACORN). This study investigated the demographic and practice characteristics as well as clinical management of chiropractors who ‘often’ treated patients with LBRLP compared to those who treated LBRLP ‘never/rarely/sometimes’. Multiple logistic regression models identified independent factors associated with chiropractors who ‘often’ treated patients with LBRLP. Results A total of 1907 chiropractors reported treating patients experiencing LBRLP, with 80.9% of them ‘often’ treating LBRLP. Chiropractors who ‘often’ treated LBRLP were more likely to manage patients with multi-site pain including axial low back pain (OR = 21.1), referred/radicular neck pain (OR = 10.8) and referred/radicular thoracic pain (OR = 3.1). While no specific management strategies were identified, chiropractors who ‘often’ treated LBRLP were more likely to discuss medication (OR = 1.8), manage migraine (OR = 1.7) and degenerative spine conditions (OR = 1.5), and treat women during pregnancy (OR = 1.6) and people with work-related injuries (OR = 1.5), compared to those not treating LBRLP frequently. Conclusions Australian chiropractors frequently manage LBRLP, although the nature of specific management approaches for this condition remains unclear. Further research on the management of LBRLP can better inform policy makers and educators interested in upskilling chiropractors to deliver safe and effective treatment of LBRLP

Corrosion Testing of Brazed Space Station IATCS Materials

Increased nickel concentrations in the IATCS coolant prompted a study of the corrosion rates of nickel-brazed heat exchangers in the system. The testing has shown that corrosion is occurring in a silicon-rich intermetallic phase in the braze filler of coldplates and heat exchangers as the result of a decrease in the coolant pH brought about by cabin carbon dioxide permeation through polymeric flexhoses. Similar corrosion is occurring in the EMU de-ionized water loop. Certain heat exchangers and coldplates have more silicon-rich phase because of their manufacturing method, and those units produce more nickel corrosion product. Silver biocide additions did not induce pitting corrosion at silver precipitate sites

Concentration and stable carbon and hydrogen isotopes of lipid biomarkers in a thermokarst lake in Arctic Alaska

Arctic lakes and wetlands contribute a substantial amount of methane to the contemporary atmosphere, yet profound knowledge gaps remain regarding the intensity and climatic control of past methane emissions from this source. In this study, we reconstruct methane turnover and environmental conditions, including estimates of mean annual and summer temperature, from a thermokarst lake (Lake Qalluuraq) on the Arctic Coastal Plain of northern Alaska for the Holocene by using source-specific lipid biomarkers preserved in a radiocarbon-dated sediment core. Our results document a more prominent role for methane in the carbon cycle when the lake basin was an emergent fen habitat between ~12,300 and ~10,000 cal yr BP, a time period closely coinciding with the Holocene Thermal Maximum (HTM) in North Alaska. Enhanced methane turnover was stimulated by relatively warm temperatures, increased moisture, nutrient supply, and primary productivity. After ~10,000 cal yr BP, a thermokarst lake with abundant submerged mosses evolved, and through the mid-Holocene temperatures were approximately 3°C cooler. Under these conditions, organic matter decomposition was attenuated, which facilitated the accumulation of submerged mosses within a shallower Lake Qalluuraq. Reduced methane assimilation into biomass during the mid-Holocene suggests that thermokarst lakes are carbon sinks during cold periods. In the late-Holocene from ~2700 cal yr BP to the most recent time, however, temperatures and carbon deposition rose and methane oxidation intensified, indicating that more rapid organic matter decomposition and enhanced methane production could amplify climate feedback via potential methane emissions in the future