The goal is to determinate the technical feasibility of using agroindustrial wastes for adsorption of dyes. The pHpzcof Brewer’s spent grains and Orange peel is 5.3 and 3.5, respectively. The equilibrium isotherms of Basic Blue 41, Reactiive Black 5, and Acid Black 1 were carried out without pHs control which ranging between 4 and 5.5. The equilibrium concentrations for both adsorbents were fitted by the Freundlich and Langmuir models. The maximum adsorption capacity measured for Basic Blue 41, Reactive Black 5, and Acid Black 1 was 32.4, 22.3, and 19.8 mg g-1for Brewer’s spent grains; and 157, 62.6, and 45.5 for orange peel, respectively. The kinetic of process was fitted by the model of pseudo-second order. The constant rate for orange peel decreased to extend the initial concentration of dye increased, obtaining 4.08 * 10−3−0.6 * 10−3(Basic Blue 41), 2.98 * 10−3−0.36 * 10−3(Acid Black 1), and 3.40 * 10−3−0.46 * 10−3 g mg−1 min−1(Reactive Black 5). The best removal efficiency was obtained in orange peel with values started from 63% to 20%. Consequently, according the results obtained there are two positive effects, the reuse of agricultural wastes and its use as low-cost adsorbent of the dyes.
Interest in production of ligninolytic enzymes has been growing over recent years for their use in various applications such as recalcitrant pollutants bioremediation; specifically, versatile peroxidase (VP) presents a great potential due to its catalytic versatility. The proper selection of the fermentation mode and the culture medium should be an imperative to ensure a successful production by an economic and available medium that favors the process viability. VP was produced by solid-state fermentation (SSF) of Pleurotus eryngii, using the agricultural residue banana peel as growth medium; an enzymatic activity of 10,800 U L(-1) (36 U g(-1) of substrate) was detected after 18 days, whereas only 1800 U L(-1) was reached by conventional submerged fermentation (SF) with glucose-based medium. The kinetic parameters were determined by evaluating the H2O2 and Mn(2+) concentration effects on the Mn(3+)-tartrate complex formation. The results indicated that although the H2O2 inhibitory effect was observed for the enzyme produced by both media, the reaction rates for VP obtained by SSF were less impacted. This outcome suggests the presence of substances released from banana peel during the fermentation, which might exhibit a protective effect resulting in an improved kinetic behavior of the enzyme.
In recent years, adsorption has been accepted as one of the most appropriate processes for decolorization of wastewaters. This paper presents experimental results on application of peat for removal of structurally diverse dyes (azo, oxazine, triphenylmethane, thiazine and others) with emphasis on relevant factors such as the adsorbate-adsorbent chemical properties and chemical interaction as well as adsorption conditions. The equilibrium experimental results were fitted to Langmuir and Freundlich isotherms to obtain the characteristic parameters of each model. According to the evaluation using the Langmuir equation, the maximum sorption capacity of basic dyes at 22 degrees C was 667 (mg g(-1)) for Basic Blue 24, 526 (mg g(-1)) for Basic Green 4 and 714 (mg g(-1)) for Basic Violet 4. On the other hand for Acid Black 1 it was only 25 (mg g(-1)). Batch kinetics studies were undertaken and the data evaluated in compliance with chemical sorption mechanisms. For all of the systems studied the pseudo-second order model provided the best correlation of the kinetic experimental data. A film-pore double resistance diffusion model for mass transfer has also been used in this study to determine the effective diffusivity, Deff, for the adsorption of basic dyes in to peat.
-The production of manganese dependent peroxidase (MnP) by Phanerochaete chrysosporium and the level of decolorization of 13 dyes were evaluated using static and agitated batch cultures and continuous cultures. A screening carried out under static conditions showed that the oxidative system has a certain affinity for azoic structures. For concentrations of 100 mg l -1 of Acid Black 1, Reactive Black 5, Reactive Orange 16 and Acid Red 27, decolorization percentages higher than 90% were obtained. In batch cultures with Acid Black 1 and Reactive Black 5 a significant increment in primary post-metabolism biomass was observed. For these last two dyes, it was possible to explore the response of the continuous system during 32 to 47 days, with concentrations between 25 to 400 mg l -1 , obtaining decolorization percentages greater than 70% for 400 mg l -1 .
ABSTRACT:The purpose of this study was to investigate the adsorption of two Basic dyes, i.e. Basic Blue 3 (BB3) and Basic Orange 2 (BO2), onto Sphagnum Magellanicum peat. The equilibrium studies were carried out at 30 o C and 45 o C, respectively. The equilibrium experimental results were fitted to the Langmuir model to obtain the characteristic parameters. The maximum sorption capacities for each dye were 41 mg/g for BB3 and 92 mg/g for BO2. The magnitude of the a L parameter increased with temperature for both dyes. The batch kinetic studies of Basic dye adsorption onto peat considered the effect of the initial concentrations of the dyes and the peat dosage. The models fitted were first order (Lagergren equation), pseudo-second order (chemisorption mechanism) and intra-particle diffusion. For all the systems studied, the pseudo-second-order model provided the best correlation. The intra-particle diffusion model provided good correlations over the intermediate and final steps of the adsorption process.
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