UV-Based Advanced Oxidation Processes of Remazol Brilliant Blue R Dye Catalyzed by Carbon Dots.

UV-based advanced oxidation processes (AOPs) (UV/H2O2 and UV/S2O82-) with a titanium(IV)-doped carbon dot, TiP-CD, as a catalyst were developed for the decomposition of Remazol Brilliant Blue R (Reactive Blue 19), an anthraquinone textile dye (at T = 25 °C and pH = 7). The Ti-CD, with marked catalytic UV properties, was successfully synthesized by the one-pot hydrothermal procedure, using L-cysteine as carbon precursor, ethylenediamine as nitrogen source, PEG (polyethylene glycol) as a capping agent, and titanium(IV) isopropoxide (precursor of TiO2 doping). Contrary to azo dyes (methyl orange, orange II sodium salt, and reactive black 5), which achieved complete degradation in a time interval less than 30 min in the developed AOP systems (UV/H2O2, UV/S2O82-, and UV/TiO2), the RBB-R showed relatively low degradation rates and low discoloration rate constants. In the presence of the catalyzer, the reaction rate significantly increased, and the pseudo-first-order rate constants for the RBB-R discoloration were UV/3.0 mM H2O2/TIP-CD-0.0330 min-1 and UV/1.02 mM S2O82-/TIP-CD-0.0345 min-1.

Copper(II)-Doped Carbon Dots as Catalyst for Ozone Degradation of Textile Dyes.

A catalytic ozonation advanced oxidation process (AOP) with a copper(II)-doped carbon dot as catalyst, Cu-CD (using L-cysteine and polyethylene glycol (PEG) as precursors and passivation agents), was developed for textile wastewater treatment (T = 25 °C and pH = 7). Four dyes were analyzed­Methyl Orange (MO), Orange II sodium salt (O-II), Reactive Black 5 (RB-5) and Remazol Brilliant Blue R (RBB-R), as well as a real effluent from the dying and printing industry. The Cu-CD, with marked catalytic ozonation properties, was successfully synthesized by one-pot hydrothermal procedure with a size of 4.0 nm, a charge of −3.7 mV and a fluorescent quantum yield of 31%. The discoloration of the aqueous dye solutions followed an apparent first-order kinetics with the following rate constants (kap in min−1): MO, 0.210; O-II, 0.133; RB-5, 0.177; RBB-R, 0.086. In the presence of Cu-CD, the following apparent first-order rate constants were obtained (kapc in min−1) with the corresponding increase in the rate constant without catalyst (%Inc): MO, 1.184 (464%); O-II, 1.002 (653%); RB-5, 0.709 (301%); RBB-R, 0.230 (167%). The presence of sodium chloride (at a concentration of 50 g/L) resulted in a marked increase of the discoloration rate of the dye solution due to generation of other radicals, such as chlorine and chlorine oxide, resulting from the reaction of ozone and chloride. Taking into consideration that the real textile effluent under research has a high carbonate concentration (>356 mg/L), which inhibits ozone decomposition, the discoloration first-order rate constants without and with Cu-CD (kap = 0.0097 min−1 and kapc = 0.012 min−1 (%Inc = 24%), respectively) were relatively small. Apparently, the Cu-CD, the surface of which is covered by a soft and highly hydrated caramelized PEG coating, accelerates the ozone decomposition and dye adsorption, increasing its degradation.

Advanced Oxidation Processes Coupled with Nanomaterials for Water Treatment.

Water quality management will be a priority issue in the near future. Indeed, due to scarcity and/or contamination of the water, regulatory frameworks will be increasingly strict to reduce environmental impacts of wastewater and to allow water to be reused. Moreover, drinking water quality standards must be improved in order to account for the emerging pollutants that are being detected in tap water. These tasks can only be achieved if new improved and sustainable water treatment technologies are developed. Nanomaterials are improving the ongoing research on advanced oxidation processes (AOPs). This work reviews the most important AOPs, namely: persulfate, chlorine and NH2Cl based processes, UV/H2O2, Fenton processes, ozone, and heterogeneous photocatalytic processes. A critical review of the current coupling of nanomaterials to some of these AOPs is presented. Besides the active role of the nanomaterials in the degradation of water contaminants/pollutants in the AOPs, the relevance of their adsorbent/absorbent function in these processes is also discussed.

The impact of climate change in wheat and barley yields in the Iberian Peninsula.

The impact of climate change on wheat and barley yields in two regions of the Iberian Peninsula is here examined. Regression models are developed by using EURO-CORDEX regional climate model (RCM) simulations, forced by ERA-Interim, with monthly maximum and minimum air temperatures and monthly accumulated precipitation as predictors. Additionally, RCM simulations forced by different global climate models for the historical period (1972-2000) and mid-of-century (2042-2070; under the two emission scenarios RCP4.5 and RCP8.5) are analysed. Results point to different regional responses of wheat and barley. In the southernmost regions, results indicate that the main yield driver is spring maximum temperature, while further north a larger dependence on spring precipitation and early winter maximum temperature is observed. Climate change seems to induce severe yield losses in the southern region, mainly due to an increase in spring maximum temperature. On the contrary, a yield increase is projected in the northern regions, with the main driver being early winter warming that stimulates earlier growth. These results warn on the need to implement sustainable agriculture policies, and on the necessity of regional adaptation strategies.

The unprecedented 2014 Legionnaires' disease outbreak in Portugal: atmospheric driving mechanisms.

A large outbreak of Legionnaires' disease occurred in November 2014 nearby Lisbon, Portugal. This epidemic infected 377 individuals by the Legionella pneumophila bacteria, resulting in 14 deaths. The primary source of transmission was contaminated aerosolized water which, when inhaled, lead to atypical pneumonia. The unseasonably warm temperatures during October 2014 may have played a role in the proliferation of Legionella species in cooling tower systems. The episode was further exacerbated by high relative humidity and a thermal inversion which limited the bacterial dispersion. Here, we analyze if the Legionella outbreak event occurred during a situation of extreme potential recirculation and/or stagnation characteristics. In order to achieve this goal, the Allwine and Whiteman approach was applied for a hindcast simulation covering the affected area during a near 20-year long period (1989-2007) and then for an independent period covering the 2014 event (15 October to 13 November 2014). The results regarding the average daily critical transport indices for the 1989-2007 period clearly indicate that the airshed is prone to stagnation as these events have a dominant presence through most of the study period (42%), relatively to the occurrence of recirculation (18%) and ventilation (17%) events. However, the year of 2014 represents an exceptional year when compared to the 1989-2007 period, with 53 and 33% of the days being classified as under stagnation and recirculation conditions, respectively.

Probabilistic fire spread forecast as a management tool in an operational setting.

BACKGROUND: An approach to predict fire growth in an operational setting, with the potential to be used as a decision-support tool for fire management, is described and evaluated. The operational use of fire behaviour models has mostly followed a deterministic approach, however, the uncertainty associated with model predictions needs to be quantified and included in wildfire planning and decision-making process during fire suppression activities. We use FARSITE to simulate the growth of a large wildfire. Probabilistic simulations of fire spread are performed, accounting for the uncertainty of some model inputs and parameters. Deterministic simulations were performed for comparison. We also assess the degree to which fire spread modelling and satellite active fire data can be combined, to forecast fire spread during large wildfires events. RESULTS: Uncertainty was propagated through the FARSITE fire spread modelling system by randomly defining 100 different combinations of the independent input variables and parameters, and running the correspondent fire spread simulations in order to produce fire spread probability maps. Simulations were initialized with the reported ignition location and with satellite active fires. The probabilistic fire spread predictions show great potential to be used as a fire management tool in an operational setting, providing valuable information regarding the spatial-temporal distribution of burn probabilities. The advantage of probabilistic over deterministic simulations is clear when both are compared. Re-initializing simulations with satellite active fires did not improve simulations as expected. CONCLUSION: This information can be useful to anticipate the growth of wildfires through the landscape with an associated probability of occurrence. The additional information regarding when, where and with what probability the fire might be in the next few hours can ultimately help minimize the negative environmental, social and economic impacts of these fires.

Effects of Recent Minimum Temperature and Water Deficit Increases on Pinus pinaster Radial Growth and Wood Density in Southern Portugal.

Western Iberia has recently shown increasing frequency of drought conditions coupled with heatwave events, leading to exacerbated limiting climatic conditions for plant growth. It is not clear to what extent wood growth and density of agroforestry species have suffered from such changes or recent extreme climate events. To address this question, tree-ring width and density chronologies were built for a Pinus pinaster stand in southern Portugal and correlated with climate variables, including the minimum, mean and maximum temperatures and the number of cold days. Monthly and maximum daily precipitations were also analyzed as well as dry spells. The drought effect was assessed using the standardized precipitation-evapotranspiration (SPEI) multi-scalar drought index, between 1 to 24-months. The climate-growth/density relationships were evaluated for the period 1958-2011. We show that both wood radial growth and density highly benefit from the strong decay of cold days and the increase of minimum temperature. Yet the benefits are hindered by long-term water deficit, which results in different levels of impact on wood radial growth and density. Despite of the intensification of long-term water deficit, tree-ring width appears to benefit from the minimum temperature increase, whereas the effects of long-term droughts significantly prevail on tree-ring density. Our results further highlight the dependency of the species on deep water sources after the juvenile stage. The impact of climate changes on long-term droughts and their repercussion on the shallow groundwater table and P. pinaster's vulnerability are also discussed. This work provides relevant information for forest management in the semi-arid area of the Alentejo region of Portugal. It should ease the elaboration of mitigation strategies to assure P. pinaster's production capacity and quality in response to more arid conditions in the near future in the region.

Integrated analysis of climate, soil, topography and vegetative growth in Iberian viticultural regions.

The Iberian viticultural regions are convened according to the Denomination of Origin (DO) and present different climates, soils, topography and management practices. All these elements influence the vegetative growth of different varieties throughout the peninsula, and are tied to grape quality and wine type. In the current study, an integrated analysis of climate, soil, topography and vegetative growth was performed for the Iberian DO regions, using state-of-the-art datasets. For climatic assessment, a categorized index, accounting for phenological/thermal development, water availability and grape ripening conditions was computed. Soil textural classes were established to distinguish soil types. Elevation and aspect (orientation) were also taken into account, as the leading topographic elements. A spectral vegetation index was used to assess grapevine vegetative growth and an integrated analysis of all variables was performed. The results showed that the integrated climate-soil-topography influence on vine performance is evident. Most Iberian vineyards are grown in temperate dry climates with loamy soils, presenting low vegetative growth. Vineyards in temperate humid conditions tend to show higher vegetative growth. Conversely, in cooler/warmer climates, lower vigour vineyards prevail and other factors, such as soil type and precipitation acquire more important roles in driving vigour. Vines in prevailing loamy soils are grown over a wide climatic diversity, suggesting that precipitation is the primary factor influencing vigour. The present assessment of terroir characteristics allows direct comparison among wine regions and may have great value to viticulturists, particularly under a changing climate.