RESUMO:Este trabalho avaliou os impactos que o aumento da concentração atmosférica de CO2 pode provocar no balanço hídrico do Cerrado, utilizando simulações feitas pelo modelo CCM3-IBIS. Foram avaliadas as condições climáticas atuais e um cenário climático futuro através da simulação controle da região e uma simulação com concentração atmosférica de CO2 elevada (cenário pessimista do IPCC). Analisando-se o Balanço Hídrico Climatológico (BHC) do Cerrado destes dois cenários, conclui-se que a deficiência hídrica da simulação com CO2 elevado (59,5 mm) é superior a da simulação controle (47,9 mm). Isto acontece devido ao aumento de temperatura do ar durante o período seco no cenário de CO2 elevado. Entretanto, o excedente hídrico da simulação com CO2 elevado (388,1 mm) também é superior ao da simulação controle (323,4 mm), pois os totais de precipitação foram maiores considerando o CO2 elevado. A deficiência hídrica no Cerrado concentra-se durante os meses de abril a setembro, que correspondem ao período seco da região. O período de excedente hídrico ocorre nos meses de novembro a março. Portanto, o BHC dos dois cenários mostra que o impacto do aumento do CO2 atmosférico varia conforme o total de precipitação da estação considerada. Na estação chuvosa o cenário de mudança climática aumenta o excedente hídrico no solo, porém durante a estação seca, ocorre um aumento de deficiência hídrica. Palavras-chaves: excedente hídrico, deficiência hídrica, CCM3-IBIS, modelagem, mudança climática IMPACT OF THE INCREASED ATMOSPHERIC CONCENTRATION OF CO2 IN CLIMATOLOGICAL WATER BALANCE OF THE CERRADOABSTRACT: This study evaluated the impacts that the increased atmospheric concentration of CO2 can cause in water balance of the Cerrado, using simulations by CCM3-IBIS model. We evaluated the current climate conditions and a future climate scenario by control simulation of the region and a simulation with high atmospheric concentration of CO2 (IPCC pessimistic scenario). Analyzing the Cerrado Climatological Water Balance (CWB) of these two scenarios, we concluded that the water deficit of simulation with high CO2 (59.5 mm) is greater than the control simulation (47.9 mm). This is due to the increase of air temperature during the dry season at high CO2 scenario. However, the water surplus of simulation with high CO2 (388.1 mm) is also higher than the control simulation (323.4 mm), because the total precipitation were higher considering the high CO2. Water stress in the Cerrado concentrates during the months
This work presents the results of the physical characterization of palygorskite and its adsorptive behaviour for three solvatochromic dyes (Nile blue chloride (NBC), methylene blue (MTB) and dithizone (DTZ)). Adsorption isotherms were used to determine the maximum adsorption of the solvatochromic dyes on the palygorskite. The characterization of palygorskite was carried out via mineralogical and chemical analysis with X-ray diffraction, X-ray fluorescence, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy, surface-charge measurement (ζ-potential), thermogravimetric analysis, textural analysis and cation-exchange capacity analysis. The material consists of palygorskite and quartz and its chemistry is dominated by SiO2, MgO and Fe2O3. The specific surface area and cation-exchange capacity of the palygorskite are 142 m2 g–1 and 41 cmol(+) kg–1, respectively. The SEM and TEM analyses showed a fibrous structure with fibres 20–100 nm long. The thermogravimetric analysis showed three endothermic events at 57.3°C, 171.8°C and 439.6°C. The adsorption capacities of the palygorskite for NBC (basic pH), MTB (basic pH) and DTZ (neutral pH) were 0.082, 0.013 and 0.102 g g–1, respectively. The adsorptions of NBC and MTB were fitted with the Langmuir isotherm model and the adsorption of DTZ was fitted with the Sips model.
Palygorskite is a clay mineral that has several industrial and environmental applications. Palygorskite main deposits in Brazil are located in the municipality of Guadalupe, Piauí. A comparative study was performed with five samples of palygorskite from different locations through ore dressing and chemical and mineralogical characterization, using the XRD, XRF and methylene blue titration techniques. According to the results, there are significant differences in the samples composition. Among them, the most significant difference was the cation exchange capacity (CEC) value, which ranged from 24.0 to 41.0 meq.100 g-1, followed by the content of some oxides and the crystalline phases present. Despite coming from the same region, the samples contained distinct impurities.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.