ABSTRACT Natural zeolites are effective adsorbent materials and low cost for removal of heavy metals compared to conventional methods. This study aimed to evaluate the effect of pH and the maximum capacity removal of copper (Cu+2) by natural zeolite available in the region of Southern Brazil (zeolite basalt - ZB) comparing its perfomance with a commercial zeolite imported from Cuba (ZC). The cation exchange capacity of the zeolites was determined by Ammonium saturation method. The particle density was taken by volumetric flask method. The effect of pH on removal was measured at pH 3.0, 4.0 and 5.0 (± 0.2) and initial concentrations of 10 and 180 mg L−1. The maximum capacity removal of Cu+2 was assessed at pH 3.0, 4,0 and 5.0 and the initial concentrations of 10, 30, 60, 90, 180 and 270 mg L−1. Quantification of Cu+2 was carried out by atomic absorption spectrometry with atomization system type air-acetylene. For the construction of the isotherms was used polynomial regression and the averaged test percentage of Cu+2 removed at different pH values was used the Scott-Knott 5% significance level. The ZC presented capacity cation exchange 40% higher than ZB, but this was not reflected in the removal capacity. There was effect of pH only for ZC in less concentration added. The maximum removal capacity was 2662 kg−1 mg for ZB and 2759 mg kg for ZC in the pH 5.0. The maximum capacity removal Cu+2 ZB is similar to ZC. The ZB can be used to remove metals in laboratory and industrial effluents with low cost.
RESUMO Zeólitas naturais são materiais adsorventes eficientes e com baixo custo para remoção de metais pesados em relação aos métodos convencionais. Este trabalho teve como objetivo avaliar o efeito do pH na capacidade máxima de remoção de cobre (Cu+2) por zeólita natural disponível na região do planalto catarinense (zeólita basalto - ZB) comparando sua eficiência com uma zeólita comercial importada de cuba (ZC). A capacidade de troca de cátions das zeólitas foi determinada pelo método de saturação por amônio. A densidade de partículas foi feita através do método do balão volumétrico. O efeito do pH na remoção foi avaliado a pH 3,0; 4,0 e 5,0 (±0,2) e concentrações iniciais de 10 mg L−1 e 180 mg L−1. A capacidade máxima de remoção de Cu+2 foi avaliada em pH 3,0; 4,0 e 5,0 e concentrações iniciais de 10, 30, 60, 90, 180 e 270 mg L−1. A quantificação do teor de Cu+2 foi realizada por espectrofotometria de absorção atômica com sistema de atomização por chama do tipo ar-acetileno. Para a construção das isotermas foi utilizado regressão polinomial e no teste de médias da porcentagem removida de Cu+2 em diferentes valores de pH foi utilizado Scott-Knott a 5% de significância. A ZC apresentou capacidade de troca de cátions 40% superior a ZB, porém isso não se refletiu na capacidade de remoção. Houve efeito do pH somente para ZC na menor concentração adicionada. A capacidade máxima de remoção foi de 2662 mg kg−1 para ZB e 2759 mg kg−1 para ZC em pH 5,0. A capacidade máxima de remoção de Cu+2 para ZB é semelhante ao da ZC. A ZB pode ser utilizada na remoção de metais em efluentes industriais e laboratoriais com baixo custo.
Cooper and zinc derived from pig slurry can accumulate in the soil, posing risks to human and animal health. The objective of this study was to determine the adsorption capacity and the competition of Cu and Zn in Oxisols that received continued applications of 200 m³ha-1year-1of pig slurry for seven years and to compare with soil under natural conditions. To evaluate the adsorption, Cu and Zn solutions were applied to the soil at concentrations of 0, 25, 50, 100, 150, 200, 400, 1.200 µmol L-1; soil:solution ratio of 1:100.Merck Certipur standard solution 1.000 mg L-1 was utilized to construct the levels of Zn and Cu. The adsorption of Cu showed a sigmoid behavior (S-type isotherm) in soil with no slurry application and linear behavior (C-type isotherm) in soil with pig slurry. The maximum adsorption of Cu in soil without pig slurry was 3,021 mg kg-1. For Zn, all the isotherms showed linear behavior. The maximum adsorption capacity of Cu and Zn was not reached in soil with slurry. These results show that the studied Oxisol has a high capacity to retain Zn and Cu from pig slurry.
O Cu e Zn oriundos dos dejetos suínos podem se acumular no solo, oferecendo riscos para a saúde humana e a animal. O objetivo deste trabalho foi determinar a capacidade de adsorção e a competição de Cu e Zn num Latossolo Vermelho distroférrico, que recebeu aplicações continuadas de dejetos suínos, com taxa de aplicação de 200 m³ ha-1 ano-1,durante sete anos, e comparar a adsorção com solo que nunca recebeu dejeto. Para avaliar a adsorção do Cu e Zn, foram aplicados ao solo soluções de Cu e Zn, nas doses de 0, 25, 50, 100, 150, 200, 400, 1.200 µmol L-1 e relação solo: solução final de 1:100. Para a obtenção das doses de Zn e Cu foi utilizada solução padrão Merck® Certipur 1.000 mg L-1. A adsorção de Cu apresentou comportamento sigmoide (isoterma tipo S), em solo sem dejeto (SD), e comportamento linear (isoterma tipo C), em solo com dejeto (CD). A capacidade máxima de adsorção (CMA) de Cu no solo SD foi de 3.021 mg kg-1. Para Zn, todas as isotermas apresentaram comportamento linear. Não foi atingida a capacidade máxima de adsorção, no tratamento CD, para Cu e Zn. Esses resultados indicam que o Latossolo estudado apresenta alta capacidade para reter o Cu e Zn oriundos dos dejetos suínos.
The earth diatomite is a material used by the industries in the filtration process and clarification of the beer. This material presents a reduced useful life due to the blockages of their pores during the filtration process. The objective of this work was to reactivate the properties of filtration of the earth diatomite, saturated with organic matter during the filtration stage, starting from a controlled thermal treatment. The obtained results demonstrated that the earth diatomite saturated with organic matter submitted to a controlled thermal treatment has their filtration properties reactivated, could be reused in the beer production process.
Characterization of the thermal decomposition of polyurethane (PUR) foams was performed by Fourier-transformed infrared (FT-IR) spectroscopy and thermogravimetric analysis (TGA). Three main weight loss paths were observed by TGA, the residue being lower than 3 wt.% for 3 different PUR foams analyzed. FT-IR spectra indicated CO2, CO, NH3 and isocyanides as main decomposition products. PUR foams of different cell sizes were immersed in a slurry of the parent glass ceramic of composition Li2O-ZrO2-SiO2-Al 2O3 (LZSA) and submitted to heat treatment. The LZSA cellular glass ceramics obtained after sintering and crystallization resembled the original morphology of the PUR foams.
Dregs is an alkaline solid by-product generated in the cellulose manufacturing industry that could be used to correct soil acidity. The present study aimed to evaluate the chemical composition of this product and some of its properties. The dregs presented 354 g kg-1 of calcium, neutralization capacity of 80.3%, and pH 10.7, besides low concentration of sodium (10.2 g kg-1), lead (62.9 mg kg-1) and cadmium (5.6 mg kg-1). Thus, it is a product that can safely be used to increase the soil pH.
The chemical durability of the Li2O-ZrO2-BaO-SiO2 system was examined by determination of the Vickers hardness. The dependence of hardness and of the chemical resistance with BaO addition was investigated. The experimental results indicate that the hardness increases with the BaO content. The samples surface's morphology submitted to the chemical treatment in acidic (H2SO4) and basic (KOH) solution was accompanied by scanning electron microscopy. The chemical durability of the materials with BaO showed better than the glass ceramic without this content. These materials treated with H2SO4 solution showed a preferential attack to the silica rich sites.
Differential thermal analysis and scanning electron microscopy were used to determine the influence of the addition of BaO on the crystallization mechanism of Li2O-ZrO2-SiO2 systems. As the concentration of BaO in the samples increased, a transition occurred in the predominant crystallization mechanism, which passed from superficial to volumetric. To determine the maximum nucleation rate, the crystallization kinetics of the sample containing 20 mole % BaO, which showed the most uniform crystallization, was studied by counting the nuclei with an image analyzer. The first nuclei appeared at the first endothermic inflection point (at the start of Tg, at 440 °C), while the maximum number of nuclei was counted at the midpoint of the glass transition region (446 °C). These results are similar to those observed for other materials that crystallize in volume, and confirm scanning electron microscopy data.