Evaluation of membrane microfiltration fouling in landfill leachate treatment

 The membrane separation capacity allows the retention of the remaining organic matter that could not be removed by the biological process, increasing the treatment efficiency. The aim of this study was to evaluate the microfiltration (MF) process in a tertiary treatment system for landfill leachate from the Rincão das Flo-res, Caxias do Sul/RS/Brazil. The microfiltration system of commercial hollow fiber membrane poly(ether-imide) was tested in oder to promote leachate treatment. The tests carried out were leachate permeation, con-centration factor, determination of fouling and obtention of the values of the resitance to the flux. The re-sistance due to fouling and flux decline were evaluated to determine the best operating conditions. The poten-tial for fouling was 53% and was evaluated by comparing the pure water permeability before and after the leachate filtration. It was observed that the resistance due to fouling express 32% of the total resistance. The results showed that the MF process allows the elimination of up to 43% of the organic matter measured as chemical oxygen demand (COD) and 63% of that measured as biological oxygen demand (BOD5).Keywords: leachate; microfiltration; fouling; membrane resistance

La correspondencia de Valencia : diario de noticias : eco imparcial de la opinión y de la prensa: Año XLIII Número 18074 - 1920 Abril 14

Copia digital. Madrid : Ministerio de Cultura. Subdirección General de Coordinación Bibliotecaria, 200

Characterization of mullite ceramic membranes and their application in the removal escherichia coli

This paper aims the morphological and structural characterization of ceramic membranes of mullite and their application in the removal of Escherichia coli. A complex irregular structure presented by the pores of the membrane was verified by scanning electron microscopy (SEM). The average pore size and distribution were determined by mercury intrusion porosimetry. The average pore size of the material presented was 0,39 μm. Microfiltration tests resulted in a protein retention of 46, 76 and 89% for trypsin (TR), egg albumin (EA) and bovine serum albumin (BSA), proving the efficiency of the membrane microfiltration tests for molecular weight of 69 kDa. The application of the membranes on the retention of gram-negative bacterium E. coli resulted in a 66% efficiency at a pressure of 200 kPa and a 98% efficiency when applied a pressure of 50 kPa. Therefore, the use of mullite membranes show limited efficiency towards bacteria retention. Nevertheless, they present fluxes similar to other materials proposed in the literature

Characterization of ethylene-vinyl acetate copolymer (EVA) residues

O resíduo de EVA apresentou teor de gel de aproximadamente 75% em massa, cerca de 20% em massa de acetato de vinila (VAc), fora processado a partir de EVA com aproximadamente 28% de VAc e possui teor de carga inorgânica de 20% em massa, segundo análises em TGA. O EVA resíduo apresentou maiores valores de módulo elástico e de dureza, e menores valores de elongação na ruptura e de resistência ao impacto Izod. O custo energético da moagem do resíduo de EVA foi calculado como sendo inferior a 5% do valor do EVA virgem.Poly[(ethylene)-co-(vinyl acetate)] (EVA) has large application in the shoes industries, especially as expanded sheets, in order to produce insoles and innersoles. Studies carried out in the south region of Brazil in 2001 have demonstrated that the residues generated by shoes industries were higher than 200 ton/month, the major part of which is composed by EVA expanded sheets. With this in mind, the objective of this work was to characterize the residues of expanded EVA and also to analyze the milling cost in order to make the recycling possible. The EVA residues presented originally a microcellular structure, which was destroyed after milling, according to SEM analysis. The EVA powder was found to be composed by two phases: a crosslinked phase (75wt%) and a soluble one (25wt%). The VAc content in EVA residues was found to be around 20wt% and it is believed that the EVA had originally ca. 28wt% of VAc before the crosslinking process, according to the TG analysis. Besides, it was found that the crosslinked structure of EVA residues make them stiffer than virgin EVA used for comparison, according to mechanical tests. The milling cost was estimated to be less than 5% compared to the virgin EVA

Characterization of Polyamide 66 membranes prepared by phase inversion using formic acid and hydrochloric acid such as solvents

The membranes properties prepared from water/formic acid (FA)/ polyamide 66 (PA66) and water/hydrochloric acid (HCl)/polyamide 66 (PA 66) systems has been studied. The different solvents interact distinctly with the polymer, affecting the membrane morphology. The asymmetric structure of the membranes showed a dense top layer and a porous sublayer. The membranes M-HCl prepared from HCl/PA 66 system showed a larger dense layer (around 23 μm) in compared to those prepared from FA/PA 66 system (M-FA) (around 10 μm). The membrane morphology was a determinant factor in results of water absorption, porosity and pure water flux. The lower thickness of dense layer in M-FA membranes resulted in a higher water absorption and, consequently, porosity, approximately 50%, compared with M-HCl membranes, approximately 15%. The same trend was observed to permeate flux, the lower thickness of dense layer higher pure water flux

Characterization of ethylene-vinyl acetate copolymer (EVA) residues

O resíduo de EVA apresentou teor de gel de aproximadamente 75% em massa, cerca de 20% em massa de acetato de vinila (VAc), fora processado a partir de EVA com aproximadamente 28% de VAc e possui teor de carga inorgânica de 20% em massa, segundo análises em TGA. O EVA resíduo apresentou maiores valores de módulo elástico e de dureza, e menores valores de elongação na ruptura e de resistência ao impacto Izod. O custo energético da moagem do resíduo de EVA foi calculado como sendo inferior a 5% do valor do EVA virgem.Poly[(ethylene)-co-(vinyl acetate)] (EVA) has large application in the shoes industries, especially as expanded sheets, in order to produce insoles and innersoles. Studies carried out in the south region of Brazil in 2001 have demonstrated that the residues generated by shoes industries were higher than 200 ton/month, the major part of which is composed by EVA expanded sheets. With this in mind, the objective of this work was to characterize the residues of expanded EVA and also to analyze the milling cost in order to make the recycling possible. The EVA residues presented originally a microcellular structure, which was destroyed after milling, according to SEM analysis. The EVA powder was found to be composed by two phases: a crosslinked phase (75wt%) and a soluble one (25wt%). The VAc content in EVA residues was found to be around 20wt% and it is believed that the EVA had originally ca. 28wt% of VAc before the crosslinking process, according to the TG analysis. Besides, it was found that the crosslinked structure of EVA residues make them stiffer than virgin EVA used for comparison, according to mechanical tests. The milling cost was estimated to be less than 5% compared to the virgin EVA

Analysis of composite membranes in the separation of emulsions sunflower oil/water

Oil is a major pollutant of water resources, affects aquatic life, causing environmental degradation. Currently there is an increase in studies of membrane applied to separation of oil-water. Among these membranes, there are composite membranes, which show as main characteristic an association of organic and inorganic membrane properties. In a tangential flow process, the ceramic tube (support) is responsible for the mechanical strength of the membrane and the selective barrier property of the membrane is established by the polymer. The aim of this work is the application of α-alumina/ polyamide 66 composite membrane in the retention of sunflower oil from oil-water emulsions and the study of resistance of such membranes in ultrafiltration processes. The α-alumina ceramic tubes were impregnated internally with a solution of polyamide 66 (PA66) (5% w/v) and tested with distilled water and sunflower oil solutions at concentrations of 50, 100 and 200 mg∙L-1. Membranes impregnated with PA66 showed a sunflower oil retention between 53.5 and 99.5% and superior membrane resistance (MR) to the permeate flux (1.92 x 1013 a 5.52 x 1013) which explains the decrease in the permeate volume

Degradation study of polypropylene (PP) and bioriented polypropylene (BOPP) in the environment

Polymers are vastly employed for numerous purposes in different industrial segments and generate soaring quantities of discarding in the environment. This research analyzed the degradability/biodegradability of polypropylene films (PP) and Bioriented polypropylene (BOPP) polymers after 11 months interred in the São Giácomo landfill in Caxias do Sul. Comparing the buried PP film to a sample of virgin PP, two peaks of degrading activity appeared at the TG curve as well as structure modification typified by occurrence of new absorption bands at FTIR, which can be credited to changes in crystallinity. Thermal analysis carried out on the buried PP and BOPP showed decreases in the percentage of crystallinity due to chain scission. The major reduction was observed in the PP, since its crystallinity is a consequence of polymerization instead of chain orientation processes, as in BOPP. Cracks and erosion of the polymer surface were detected in both PP and BOPP, indicating degrading processes by microorganisms