Development of granular sludge for textile wastewater treatment

Microbial granular sludge that is capable to treat textile wastewater in a single reactor under intermittent anaerobic and aerobic conditions was developed in this study. The granules were cultivated using mixed sewage and textile mill sludge in combination with anaerobic granules collected from an anaerobic sludge blanket reactor as seed. The granules were developed in a single sequential batch reactor (SBR) system under alternating anaerobic and aerobic condition fed with synthetic textile wastewater. The characteristics of the microbial granular sludge were monitored throughout the study period. During this period, the average size of the granules increased from 0.02 ± 0.01 mm to 2.3 ± 1.0 mm and the average settling velocity increased from 9.9 ± 0.7 m h⁻¹ to 80 ± 8 m h⁻¹. This resulted in an increased biomass concentration (from 2.9 ± 0.8 g L⁻¹ to 7.3 ± 0.9 g L⁻¹) and mean cell residence time (from 1.4 days to 8.3 days). The strength of the granules, expressed as the integrity coefficient also improved. The sequential batch reactor system demonstrated good removal of COD and ammonia of 94% and 95%, respectively, at the end of the study. However, only 62% of color removal was observed. The findings of this study show that granular sludge could be developed in a single reactor with an intermittent anaerobic-aerobic reaction phase and is capable in treating the textile wastewater.     

The Influence of Process Parameters on the Properties of PLGA‐Microparticles Produced by the Emulsion Extraction Method

Controlled release poly(lactic‐co‐glycolic acid) microparticles for use as active pharmaceutical ingredient carriers were prepared by the emulsion extraction method. Particle formation experiments were carried out in a stirred vessel. The local flow conditions in these experiments, that is, local shear rates and dissipation rates, and the extraction rate of the organic solvent were examined by a computational fluid dynamics (CFD) simulation. The local flow conditions in the stirred tank reactor have a significant influence on the final properties, specific surface area, skeletal density, organic solvent content, and size of the microparticles. We determined nondimensional correlations for predicting these particle properties as functions of the process parameters as, for example, the stirrer speed, emulsion injection point, and oil droplet size in the initial emulsion. The results demonstrate that CFD simulations offer insight into the particle formation process for different batch sizes and provide a basis for scale‐up and optimization of the process. © 2012 American Institute of Chemical Engineers AIChE J, 59: 1868–1881, 2013     

Supercritical fluid extraction of lycopene from tomato juice and characterization of its antioxidation activity

A new method to extract lycopene from tomato juice using supercritical CO₂ as solvent and without the need to dry the raw material is presented. To conduct the extraction, the tomato juice was subjected to cycles of centrifugation followed by rinsing with absolute ethanol to partially remove the water present in the solid part of the juice. The influence of the temperature and pressure on the extraction efficiency and on the extract antioxidant activity was studied using a factorial experimental design. The extraction efficiency varied from 7.7% to 76.7% and only extraction temperature had a statically significant effect on the process. The reversed phase HPLC analysis showed that lycopene is the major compound of the extract. The extract that presented higher antioxidant activity was obtained at 40 °C and 350 bar with 12.7 mmol L⁻¹ Trolox/g of extract using the DPPH radical scavenging method and 61.3 mmol L⁻¹ Trolox/g of extract using the rubrene singlet oxygen quenching method.     

Formation of a Rhenium-base Diffusion-barrier-coating System on Ni-base Single Crystal Superalloy and its Stability at 1,423 K

A diffusion-barrier-coating system having a duplex structure comprised of an inner Re(W)–Cr–Ni layer and an outer Ni-aluminide layer was formed on a fourth generation, single-crystal Ni-base superalloy by using electroplating of Re(Ni) and Ni(W) films, Al- and Cr- (high-Cr and low-Cr) pack cementations, and a combination of the two treatments. With the ReW-high-Cr coating, fine needle- or plate-like precipitates formed in the alloy substrate below the inner Re(W, Cr, Ni) layer, while there was little of this precipitate with the ReW-low-Cr pack-cementation coating. The inner, Re-base alloy layer in the ReW-high-Cr coating was identified to be a σ-(Re,Cr,W,Ni) phase, while the inner layer of the ReW-low-Cr was a mixture of σ-(Re,Cr,W,Ni) and δ-Re(Cr,W,Ni) phases. After heating the coated alloys at 1,150 °C for 100 h in air, the outer Al reservoir layer became β-NiAl containing (31–33)Al with α-Cr particles and fine precipitates of γ′-Ni₃Al with both the ReW-high-Cr and ReW-low-Cr treatments. In the case of the ReW-high-Cr coating there were numerous light-colored, needle-like precipitates formed deep in the alloy substrate under the inner layer, while in the case of the ReW-low-Cr coating γ′ appeared near the inner layer. It was found that the inner, Re-base alloy layer acted as a diffusion barrier, and that its structure was maintained with little change in composition after 100 h of oxidation at 1,150 °C. K. Z. Thosin is from Indonesian Institute of Sciences, LIPI.     

Adsorption of aluminium from wastewater by chitin and chitosan produced from silkworm chrysalides

Chitin, extracted from silkworm chrysalides, was employed for the production of a high‐purity and porous chitosan, as observed by scanning electron microscopy. Chitin and the chitosan produced from it were also analysed using ¹³C NMR spectroscopy to show the efficiency of deacetylation. The extracted chitin was investigated as an adsorbent material for aluminium removal from textile wastewater, by the column chromatographic method. After the treatment, the residual aluminium was lower than the limitation criterion of 0.2 mg L^?1. The isotherms of adsorption on chitin and chitosan surfaces were investigated and the best fits were observed using the Freundlich isotherm. At pH 5.0, the maximum adsorption capacity was 21.3 mg of aluminium per gram of chitosan over 70 h of experiments. Copyright © 2006 Society of Chemical Industry     

Creamatocrit as a rapid method to estimate the contents of total milk lipids

The Gerber test has been extensively used as an extremely accurate standard method for determining the content of milk lipids. However, it is risky to laboratory workers and hazardous to the environment due to the need for use of reagents. The research and development of alternative methods is of great importance especially for industrial application. In this work, the Creamatocrit method is evaluated to estimate the content of milk fatty material from mammals. Capillary tubes were filled with milk samples and centrifuged at 15 000 rpm for 5 min using an adequate micro centrifuge. The total content of lipids was determined by taking the ratio between the cream phase and the total sample length within the capillary tube. The results obtained show a satisfactory correlation (0.968) between the Creamatocrit and Gerber methods. Thus, we propose the use of the Creamatocrit method as an advantageous alternative to the Gerber method for industrial purposes.     

Buyers’ purchasing time and herd behavior on deal-of-the-day group-buying websites

Since its introduction 10?years ago, group-buying websites, where buyers with similar purchase interests congregate online to obtain group discounts, have metamorphosed into several variants. The most popular variant is the deal-of-the-day group-buying website, where there is only one product/service being offered each day. Starting in the United States in 2008, this new group-buying variant has rapidly achieved tremendous success and has been widely adopted in various countries. At the end of August 2010, there were more than 1000 deal-of-the-day group-buying websites in the most competitive online marketplace, i.e., China. How exactly do buyers behave on these websites? How can deal-of-the-day group-buying website providers take advantage of buyers?? behavior? Based on herd behavior, we collected and analyzed over 500 hourly orders on the most popular deal-of-the-day group-buying website in Beijing. We found that auction times and new orders for each hour have an inverted-U relationship. Moreover, we discovered that the number of existing orders will only have a positive effect on the number of new orders during the first half of the day. Contributions to research and implications for group-buying website providers are presented in the paper.     

Construction and Evaluation of an Opto-Coupled Potentiostat with a PC/PDA Interface

Abstract

The design, construction, and characterization of a portable opto-coupled potentiostat are presented. The potentiostat is battery-powered, managed by a microcontroller, which implements cyclic voltammetry (CV) using suitable sensor electrodes. Its opto-coupling permits a wide range of current measurements, varying from mA to nA. Two software interfaces were developed to perform the CV measurement: a virtual instrument for a personal computer (PC) and a C-base interface for personal digital assistant (PDA). The potentiostat has been evaluated by detection of potassium ferrocyanide in KCl medium, both with macro and microelectrodes. There was good agreement between the instrumental results and those from commercial equipment.     

Obtention of plant peroxidase and its potential for the decolorization of the reactive dye Remazol Turquoise G 133%

Peroxidases can be used in the decolorization process. There is a growing interest for new sources of this enzyme and for obtaining economically viable processes. In this work, a low-cost vegetable peroxidase extraction process is proposed; the resulting enzyme is characterized to determine its optimum pH, temperature, and stability conditions, and it is then applied in the decolorization of reactive dye Remazol Turquoise G 133%. The turnip peroxidase (TP) was utilized as an enzymatic source. This enzyme exhibited maximum activity at pH 7.0, and it was active in the temperature range of 30 to 50 °C, which favors its use in industrial processes. Acetone was the most efficient solvent to induce precipitation. The removal of Remazol Turquoise G 133% was 56.0% complete after 50 min, while 41.0% of the same dye was removed with the commercial horseradish peroxidase enzyme in 50 min. TP presents potential as a viable alternative in the decolorization of textile wastewaters.