This work is focused on the production of struvite as an alternative to reduce the concentration of phosphorus and nitrogen from swine wastewater. The effect of Mg source (MgO and MgCl2. 6H2O) and pH on nitrogen and phosphorus removal was investigated. From the results was seen that N and P were efficiently removed from swine wastewater. Data of X-ray diffraction (XRD) revealed that the production of struvite in the crystalline form is dependent of pH, which was obtained only in the runs carried out at pH 9.5, independent of Mg source employed. The production of struvite showed to be effective for adding value to swine wastewater.

Rice husk ashes are a potential source of pollution, thus there is continued interest in its recycling. An environmentally friendly solution is its conversion into products such as aluminosilicates that are designed for use as fertilizer. Aluminosilicates that present a high cationic exchange capacity becomes an excellent material to be used in soil for accumulating and liberating nutrients slowly to the plants. The aim of this study is to investigate the effects of the alkali concentration in the cationic exchange capacity of an aluminosilicate obtained from rice husk ashes. The obtained products were characterized by X-ray diffraction, scanning electron microscopy, atomic absorption spectroscopy, and cationic exchange capacity. The particles that were produced are composed of crystals smaller than 5 μm. The experimental conditions employed in this work produced a semi-crystalline aluminosilicate with a high cationic exchange capacity. The alkali concentration used had an influence on this property.

The objective of this work was to synthesize zeolitic products using rice husk ash (RHA) as silicon source. For the synthesis, two mineralizing agents: NaOH and KOH were tested. Chemical composition of the synthesized samples as well as their cation exchange capacity (CEC) were determined. The samples were also characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Formation of structure LTA (zeolite A) with NaOH as mineralizing agent was verified. The zeolitic materials presented high capacity of cation exchange, in the range of 5-6 meq/g.

O objetivo dessa investigação foi avaliar um possível efeito de infecções por nematóides sobre os níveis de anticorpos anti-HBs no soro de escolares de sete anos de idade, vacinados ao nascer com a vacina recombinante para hepatite B. Anticorpos anti-HBs e anti-HBc foram avaliados no soro de 100 escolares portadores de pelo menos um nematóide intestinal e/ou uma reação sorológica positiva para anticorpos anti-Toxocara e em 95 escolares sem helmintíases intestinais e sem anticorpos séricos anti-Toxocara, todos matriculados em escolas primárias públicas situadas na periferia urbana de Vitória, ES, Brasil. Nas 195 crianças, a mediana dos títulos dos anticorpos anti-HBs foi 31,3UI/ml, e a freqüência de títulos inferiores a 10UI/ml foi de 33,8% (IC a 95%:27,1- 40,4%). Não houve diferença significativa entre as medianas dos títulos de anti-HBs ou da freqüência de títulos inferiores a 10 UI/ml entre as crianças com ou sem helmintos (29,5 e 32,9 UI/ml e 33 e 34,7%, respectivamente; p >0.05). Mesmo quando comparadas crianças com nematóides intestinais e/ou anticorpos anti-Toxocara com eosinófilos circulantes acima de 600/mm³, com crianças sem infecção com nematóides intestinais e sem anticorpos anti-Toxocara, com menos de 400 eosinófilos/mm³, aquelas diferenças não foram significativas. Nenhuma das crianças apresentou anticorpos anti-HBc. Em conclusão, infecções com nematóides intestinais e/ou presença de anticorpos anti-Toxocara não interferem nos títulos de anticorpos anti-HBs em crianças de sete anos de idade, vacinadas ao nascer com a vacina recombinante para hepatite B.

The aim of this investigation was to evaluate the possible effect of nematode infection on anti-HBs antibody levels in the serum of seven-year-old schoolchildren vaccinated at birth with the recombinant hepatitis B vaccine. Anti-HBs and anti HBc antibodies were evaluated in the sera of 100 schoolchildren with at least one intestinal nematode and/or a positive serological reaction for anti-Toxocara antibodies and in 95 schoolchildren without intestinal helminthiasis or serum anti-Toxocara antibodies. Both groups were from public elementary schools located on the urban periphery of Vitória, ES, Brazil. Among these 195 children, the median anti-HBs antibody titer was 31.3IU/ml and the frequency of titers less than 10IU/ml was 33.8% (95% CI: 27.1-40.4%). There were no significant differences between the medians of anti-HBs titers or the frequency of titers less than 10IU/ml between the groups with or without helminthes (29.5 and 32.9IU/ml and 33 and 34.7%, respectively; p>0.05). Even when the children with intestinal nematodes and/or anti-Toxocara antibodies and with blood eosinophil counts over 600/mm³ were compared with children without infection from intestinal nematodes and without anti-Toxocara antibodies, with blood eosinophil counts less than 400 eosinophils/mm³, these differences were not significant. None of the children presented anti-HBc antibodies. In conclusion, infections with intestinal nematodes and/or the presence of anti-Toxocara antibodies did not interfere with the anti-HBs antibody titers in seven-year-old children vaccinated at birth with the recombinant hepatitis B vaccine.

In this work, a bentonite clay from Mendoza, Argentina was activated with H2SO4 (4 and 8 N) at 90ºC for 2 and 3.5 hours. Under these conditions several cations were removed from the octahedral sheet (Mg, Al, and Fe) and the DTA-TGA curves of the solids obtained after treatment were modified. Treatment time and acid concentration increased the degree of destruction of the bentonite structure. Activated samples were tested in order to verify their capacity to bleach soybean oil and were compared to a standard commercial bleaching clay. Treated samples are more efficient in bleaching than the standard.

A spent clay from the oil refining industry was recycled through an extraction process using organic solvents for removal of residual oil, followed by reactivation through heat treatment. The solvents used showed the following order in the efficiency of oil extraction: methylethylketone> acetone > petroleum ether @ hexane. The bleaching efficiency of regenerated clay samples for soybean oil was determined spectrophotometrically in the visible region. For comparison of the bleaching experiments, a sample of virgin commercial clay was used. Results showed that extraction process, using just solvent, is insufficient to recover the bleaching power of the spent clay, needing then a further high temperature treatment. The bleaching power of the regenerated clay is dependent of temperature and time of calcination. The regenerated clay samples presented a similar bleaching efficiency for soybean oil comparable to a virgin commercial clay utilized as reference.

The kinetics of the gas-phase isomerization of β-pinene over an acid-activated bentonite clay has been investigated in a fixed-bed continuous flow reactor, at atmospheric pressure between 58 and 90 oC. The major isomers produced were camphene, α-pinene and limonene. The reaction rates of β-pinene conversion and the apparent activation energy were determined. The kinetics of β-pinene isomerization was described by zero-order kinetics with an activation energy of 30-35 kJ/mol for the major products formed.