Angélica Marquetotti Salcedo Vieira

Improvement of the coagulation/flocculation process using a combination of Moringa oleifera Lam with anionic polymer in water treatment

The objective of this study is to investigate the impacts of anionic polymer as a flocculant aid on the coagulation/flocculation performance with a saline solution of Moringa oleifera as a coagulant to provide larger flocs and decrease the time sedimentation. For the tests, raw water was used from Pirapó River Basin (Maringá, Paraná, Brazil). Optimization of coagulation/flocculation tests was initially performed in a jar-test with a dosage of M. oleifera Lam (crude extract – MO, oil-extracted with ethanol – MO (et) and hexane – MO (hex) 1% m/v) as the coagulant that ranged from 10 to 60 mg L−1 and of the anionic polymer 0.1% as a flocculant aid with a dosage that ranged from 0 to 0.4 mg L−1. The parameters analysed were colour, turbidity and compounds with absorption in UV254nm. In view of the statistical analysis results, MO (hex) with a dosage of 30 mg L−1 was chosen as a coagulant for the next tests of coagulation/flocculation. When anionic polymer was used alone (0.0 mg L−1 of MO (hex)), parameters were not removed and there was no generation of heavy flocs as compared with the combination of MO (hex) with the anionic polymer. Statistical analysis showed that MO (hex) obtained the highest removals of the parameters analysed in lower dosages and no significant increase in parameters removal was observed when the polymer dosage was increased. The efficacy of the coagulant+anionic polymer was optimal when 30 mg L−1 of MO (hex) was used as a coagulant and 0.1 mg L−1 of the anionic polymer was used as a flocculant aid, decreasing the time sedimentation from 1 h to 15 min.

Antioxidant and rheological properties of guava jam with added concentrated grape juice

BACKGROUND Guava jam enriched by the addition of concentrated grape juice in the proportion of 30% (w/w) (ENR) was studied for its antioxidant potential and rheological behavior. Total phenolics content, 1,1-diphenyl-2-picrylhydrazyl radical (DPPH(•)) scavenging activity and β-carotene-linoleic acid coupled oxidation assays were used to evaluate the antioxidant properties of the samples during storage for 90 days at room temperature (25°C). RESULTS The ENR showed a total phenolic content of 11.09 g GAE kg(-1) of jam at production, more than two-fold the phenolic content presented by the standard formulation (STA). For the ENR formulation the antioxidant capacity increased in almost 20% (P ≤ 0.05) with time on the β-carotene assay and decreased with time on the DPPH assay. The enriched guava jam exhibited a non-Newtonian shear-thinning behavior at temperatures ranging from 25 to 55°C, and, moreover, presented higher stability than the standard formulation when exposed to temperature variation. CONCLUSION ENR constitutes an original food product with a notable antioxidant potential, even greater than the potential presented by the standard guava jam, worldwide appreciated delicacy.

Environmentally friendly biosorbents (husks, pods and seeds) from Moringa oleifera for Pb(II) removal from contaminated water

ABSTRACT Lead is a heavy metal considered highly toxic, responsible for causing several health problems as well as being extremely harmful to fauna and flora. Given this fact, several techniques have been studied for the removal of this metal from contaminated water, in which stands out adsorption. In this sense, the objective of this study was to evaluate the potential of lead(II) biosorption from contaminated water by seed husks, seeds and pods of Moringa oleifera Lam (moringa). Biomass was characterized by energy-dispersive X-ray spectroscopy, Scanning Electron Microscopy and Fourier transform infrared spectroscopy analyses. From the studied parameters, the optimal conditions obtained for the three analyzed biosorbents are: 30 min to equilibrium, pH 6 and 25°C temperature. The pseudo-second-order kinetic model was the best fitted to the experimental data for the three evaluated biosorbents. Regarding the adsorption isotherms, the model that best fitted to the experimental data for seed and seed husk was that proposed by Freundlich, and for the pod the Langmuir model. The analysis of the obtained thermodynamic data showed that the adsorption process is favorable and of exothermic nature. Through the results it was concluded that the evaluated biosorbents are efficient in lead(II) biosorption.

Microbial populations of an upflow anaerobic sludge blanket reactor treating wastewater from a gelatin industry.

The microbial populations of an upflow anaerobic sludge blanket reactor, used for treating wastewater from the gelatin industry, were studied by microbiological methods and phase-contrast and electron microscopy. Microscopy examination of the sludge showed a complex mixture of various rod-shaped and coccoid bacterial pluslong filaments and verymobile curved rods. In addition free-living anaerobic ciliates and flagellates were also observed. The trophic group population observed in decreasing order of dominance were hydrolytic and acetogenic at 10(6) and sulfate reducing and methanogenic at 10(5). The rate of methane production in anaerobic granular sludge cultivated in growth medium supplement with formate pressurized with H2:CO2 showed a significant increase in methane yield compared with theseed culture containingthe same substrate and atmosphere of N2:CO2. Similar rates of methane production were observed when the growth medium was supplemented with acetate pressurized either with H2:CO2 or N2:CO2. The number of total anaerobic bacteria at 10(7), fecal coliforms and total coliforms at 10(6), and fecal streptococci at 10(3) is based on colony counts on solid media. The four prevalent species of facultative anaerobic gram-negative bacteria that belong to the family of Enterobacteriaceae were identified as Escherichia coli, Esherichia fergusonii, Klebsiella oxytoca, and Citrobacter freundii. The species Aeromonas hydrophila, Aeromonas veronii, Acinetobacter iwoffi and Stenotrophomonas maltophila were the most frequently isolated glucose fermenting and nonfermenting gram-negative bacilli.

Activated carbon of Babassu coconut impregnated with copper nanoparticles by green synthesis for the removal of nitrate in aqueous solution

ABSTRACT The present study was conducted to impregnate the surface of a carbon of vegetable origin with copper nanoparticles by the green synthesis method with the aqueous extract of Hibiscus sabdariffa flowers, rich in phenolic compounds, which are responsible for the reduction and impregnation of metal nanoparticles. Batch adsorption assays were conducted aimed at nitrate removal with pure (GAC) and impregnated (IGAC) carbon, for comparative purposes. It was found that impregnation increases the efficiency of the carbon by four times in terms of the maximum adsorption capacity, which was 10.13 mg g−1 at 45°C for GAC and 45.01 mg g−1 at 15°C for IGAC, indicating that this is a promising material for the removal of nitrate in waters with an excess of this ion.

Effects of Triton X-100 and PEG on the Catalytic Properties and Thermal Stability of Lipase from Free and Immobilized on Glyoxyl-Agarose

Background: Candida rugosa Lipase (CRL) shows a very low alkaline stability that comprises its immobilization on glyoxyl-agarose, which requires pH above 10. In this way, an adaptation from the original method was used; an enzyme solution at pH 7 was slowly added at a suspension of glyoxyl-agarose prepared in bicarbonate buffer, pH 10. This change of protocol was enough for allowing the preparation of derivatives actives of CRL on glyoxyl-agarose and verifying the effect of this modified procedure on the properties of the immobilized enzyme. The effect of the additives Triton-X-100 and polyethylene glycol (PEG) on the enzymatic activity recovery and immobilized enzyme stability was evaluated. Methods: The glyoxyl-agarose support was prepared by etherification of 6% agarose beads with glycidol and further oxidation with sodium periodate. CRL was immobilized covalently on glyoxyl-agarose support in the absence and presence of 1% (w/v) Triton-X-100 or 5 g L-1 polyethylene glycol (PEG). The lipolysis activity of the free and immobilized enzyme was determined at 37ºC and pH 7.0, using p-nitrophenyl palmitate (p-NPP) as substrate. Profiles of temperature-activity (37-65ºC, pH 7.0) and pH-activity (6.0-9.5, 37ºC) were evaluated as well as thermal (45ºC and pH 8.0) and operational (15 min batches of p-NPP hydrolysis at 50ºC and pH 8.0) stabilities of free and immobilized CRL. Results: Using a single modification of the original protocol, the CRL poorly stable under alkaline conditions could be immobilized on glyoxyl-agarose in its active conformation (recovered activity varying from 10.3 to 30.4%). Besides, the presence of a detergent (Triton-X-100) and an enzyme stabilizer (PEG) contributed to the preparation of more active and more stable biocatalysts, respectively. CRL immobilized on glyoxyl-agarose in the presence of PEG was around 5 times more stable than the free CRL and around 3 times more stable than the CRL immobilized on glyoxyl-agarose in absence of PEG. The higher stability of the CRL-glyoxyl derivative prepared in the presence of PEG allowed its reuse in four successive 15 min-batches of p-nitrophenyl palmitate hydrolysis at 50ºC and pH 8.0. Conclusion: The technique of immobilizing enzymes covalently on glyoxyl-agarose showed promising results for Candida rugosa lipase (CRL). The derivatives prepared in the presence of the additives retained two to three times more activity than those prepared in the absence of additives. The enzyme immobilized in presence of PEG was about three times more stable than the enzyme immobilized in absence of this additive. Maximum catalytic activity of the immobilized CRL (in absence of additives) was observed in a temperature 10ºC above that for the free enzyme and the pH of the maximum activity was maintained in the range 6.5-7.5 for free and immobilized CRL.

Application of Hybrid Process of Coagulation/Flocculation and Membrane Filtration to Water Treatment

Nowadays, the concern about contamination of aquatic environments has increased, especially when water is used for human consumption (Madrona et al., 2010). Contamination of water resources, especially in areas with inadequate sanitation and water supply, has become a risk factor for public health, with water playing a role as a vehicle for transmission of biological agents (viruses, bacteria, and parasites) as well as a source of contamination by chemicals (industrial effluents). Among the waterborne diseases, enteric diseases are most frequent. Approximately 19% of waterborne gastroenteritis outbreaks in the United States are attributed to protozoan parasites (Lindquist, 1999), particularly Giardia and Cryptosporidium species, due to their wide distribution in the environment, high incidence in the population, and resistance to conventional water treatment (Iacovski et al., 2004).

Application of modified membranes in drinking water treatment

This paper presents filtration results obtained with commercial acetate membrane with a pore diameter of 0.45 μm, unmodified and modified with TiO2, bearing in mind drinking water treatment. The experimental filtration set-up that was used consisted in the gravitational filtration system, whereas the accomplished tests that were endured consisted of hydraulic permeability of the modified and unmodified membranes, treatment of polluted water with E. coli bacterium, color removal, turbidity and free chlorine. The results of hydraulic permeability showed similar flux for all membranes at the end of the experiments, between 25 and 30 kg·m· h. The retention results for color, turbidity and E.coli bacteria are comparable.

AVALIAÇÃO DO POTENCIAL DA SEMENTE DE MORINGA OLEIFERA PARA OBTENÇÃO DE COAGULANTE E ÓLEO UTILIZANDO ULTRA-SOM

RESUMO Os produtos resultantes da arvore Moringa oleifera (Moringa) apresentam um vasto potencial tecnologico, pois abrangem positivamente varios aspectos, tais como baixo custo, alto valor nutricional, oleo rico em acido o leico e tocoferois, alto poder coagulante e facil adaptacao em climas tropicais. Estudos relatam que mesmo apos a retirada do oleo da semente, a torta resultante con tinua com suas propriedades coagulantes, ou seja, e possivel obter o oleo e uti lizar a torta para obtencao do coagulante natural utilizado no tratamento de aguas . O objetivo do presente estudo foi avaliar o potencial da semente de Moringa para obte ncao de oleo de boa qualidade utilizando um processo quimico empregando o ultrassom e o hexano como solvente, e o processo mecânico. Foram avaliados a utilizacao do farelo desengordurado nos dois processos de extracao como agente coagulante em comparacao ao farelo integral. Os resultados mostram um alto teor de oleo (33%) em processos quimicos de extracao em comparacao a processos mecânicos (26%), sendo que o oleo apresentou boa qualidade, com indice de acidez de 0,54 e 0,44 (% em acido ole ico), respectivamente para extracao com ultrassom e prensa. Quanto ao potencial coagulante a torta desengordurada utilizando o ultrassom apresentou alto potencial de remocao de cor (92,45%) e turbidez (93,55%) da agua superficial alem de adicionar menor quantidade de materia orgânica na agua tratada quando comparada com coagulante produzido pela semente integral.

SÍNTESE VERDE DE NANOPARTÍCULAS DE COBRE IMPREGNADAS EM CARVÃO ATIVADO PARA REMOÇÃO DE NITRATO DA ÁGUA

RESUMO Nanoparticulas metalicas apresentam funcionalidades adsorventes, assim como o carvao ativado. Combinando as propriedades de ambos, por meio de impregnacao, e possivel produzir um material que atenda a uma lista de aplicacoes para adsorcao de contaminantes em agua. Existem diferentes metodologias de impregnacao, no entanto, estas sao caras e utilizam produtos poluentes. Assim, o presente trabalho objetiva o desenvolvimento de um processo de sintese “verde”, isto e, ambientalmente correto, para impregnacao das nanoparticulas de cobre em carvao ativado utilizando extratos de folhas de Moringa oleifera, a fim de remover nitrato da agua. Para isso, solucoes de cobre com diferentes concentracoes foram adicionadas ao carvao ativado juntamente com o extrato de folhas de moringa. Em seguida, foram separados por filtracao e secos, sendo caracterizados por BET, MEV, MET e EDS. Foram realizados experimentos de adsorcao para avaliar a eficiencia de remocao de nitrato da agua, sendo as concentracoes determinadas por espectrofotometria UV. Os resultados confirmaram a impregnacao das nanoparticulas metalicas de cobre sobre o carvao e que os mesmos possuem elevada area superficial, apresentando remocao significativa de nitrato apos os testes de adsorcao. Assim, pode-se concluir que a sintese “verde” para impregnacao em carvao ativado foi eficiente e que os materiais produzidos sao potenciais adsorventes para remocao de contaminantes da agua, como o nitrato.