Odelsia Leonor Sanchez de Alsina

Estudo do equilíbrio e cinética da biossorção do pb2+ por saccharomyces cerevisiae

The biosorption, based on the use of biomass for removal of ions is distinguished as an innovative and promising technology when compared with the traditional methods. In this context, the aim of the present work is to use Saccharomyces cerevisiae as biosorbent for the retention of Pb2+ metal ions. Factorial design was used for evaluation of the process. The observed equilibrium data were well described by Langmuir and Freundlich adsorption isotherms. The maximum adsorption capacity was 1486.88 mg/g. The results indicated that Saccharomyces cerevisiae is suitable for biosorption of Pb2+ metal ions.

DESEMPENHO DE BIOMASSAS NA ADSORÇÃO DE HIDROCARBONETOS LEVES EM EFLUENTES AQUOSOS

Removal of hydrocarbons from aqueous effluents using biosorbents was investigated. The effluent was simulated by a dispersion of gasoline (simple hydrocarbons) in water. Corn-cob, wood powder, coconut mesocarp and sugar-cane bagasse were used as adsorbents and their performance verified by means of batch experiments performed in an agitated vessel. The influence of input variables such as hydrocarbon concentration, mass of biomass and agitation level on the adsorbents capacity was studied by means of factorial design. The results indicated that, among the materials studied, coconut mesocarp and sugar-cane bagasse can be considered promising biomasses for treating aqueous effluents contaminated by hydrocarbons.

Fluid-Dynamic Study of Deformable Materials in Spouted-Bed Dryer

The present work is concerned with a fluid-dynamic study in spouted beds using deformable dice pieces of red guava. Data are presented on structural variations of the bed due to changes of regime during drying. Variation of physical properties (size and density) results from the volumetric shrinkage of these materials. Alterations in the fluid-dynamic stability of the spouted bed were correlated with Archimedes number. Along the process, the transition from fixed bed to fluidization can be observed, followed by stable spout and slugging. Mapping of the different regimes as a function of the moisture content is also presented.

Characterization of a tubular electrochemical reactor for the degradation of the commercial diuron herbicide

ABSTRACT After designing and constructing an electrochemical reactor with concentric electrodes and tangential feed (RECT), it is necessary to characterize it and to study its performance. The experimental study of the residence time distribution (RTD) was conducted for flow rates of 2.78u2009×u200910–6u2005m3u2005s–1, 8.33u2009×u200910–6u2005m3u2005s–1 and 13.9u2009×u200910–6u2005m3u2005s–1. According to the values obtained from the Pe number (0.67–1.52), the RECT fits as tubular with great dispersion. The determined empirical correlation (Shu2009=u200918.16 Re0.50 Sc0.33) showed a laminar flow behavior in the range of Reynolds number (Re) between 23 and 117. In order to use RECT in effluent treatment, an electrochemical oxidation study of the Diuron model molecule (Nortox®) was performed to analyze reactor performance in a closed system with total reflux. A decay kinetics of pseudo-first order was associated with the decay of the concentration of diuron and 30% mineralization in 180 min of process were obtained, having a total volume of 4u2009×u200910–3u2005m3 and an initial concentration of commercial Diuron in 215.83u2005mgu2005dm–3. Eleven by-products were identified by HPLC–MS analysis and, from this, it was possible to propose a route of degradation of the diuron. From these observations, it can be inferred that the studied electrochemical reactor had applicability in the degradation of recalcitrant compounds, as is the case of commercial diuron. Make some changes in the electrochemical reactor studied and other advanced oxidative processes, such as electro-Fenton, can be associated with the studied system to achieve a better conversion efficiency. GRAPHICAL ABSTRACT

Petroleum Wastewater Purification by Biomass Adsorption: Dynamics and Performance of a Fixed Bed Column

The effect of operational variables on the adsorption of organic pollutants in a fixed bed of biomass was studied. Dispersions of commercial gasoline in water were used as synthetic effluents to simulate petroleum effluent contaminated by organic products. Coconut mesocarp and sugar cane bagasse in the natural form were used as biomass adsorbents. The influence of input gasoline concentration, operational flow rate and fixed bed depth of biomass on the dynamic behaviour of the fixed bed column was investigated. The bed performance was evaluated by means of a 23 factorial design plus star configuration with three experiments in the central point and the average exit gasoline concentration as the response variable. In general, the coconut mesocarp gave better results than the sugarcane bagasse. Depending on the operational conditions, it was possible to obtain effluents which were virtually free from organic contaminants.