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In this work, the scale up of olive stone columns for water purification, based on results from the biosorption of Cr(III) onto olive stone in a fixed bed column at pilot scale, was developed. Pilot-scale experiments were carried out in a fixed bed column to test the influence of various parameters (flow rate, bed depth, and initial chromium concentration) on breakthrough curves. Mathematical relationships were developed to describe Cr(III) biosorption in fixed bed column of olive stone at pilot scale. The results were found to be consistent with the previous published results obtained from laboratory scale. The bed depth service time (BDST), the Adams–Bohart, the Thomas, the Yoon and Nelson, and the Dose–Response models were used to analyze the experimental data and the model parameters were evaluated. The BDST allowed comparison between performances of pilot- and laboratory-scale columns, and Dose–Response model showed good agreement of the experimental breakthrough curves with model predictions. The results showed that when the initial Cr(III) concentration was increased from 10 to 80 mg/L, the corresponding biosorption bed capacity increased from 0.126 to 0.262 mg/g at constant flow rate and bed depth. Also, breakthrough time varies from 30 to 220 min when the bed height increases from 21.5 to 62.0 cm at constant flow rate and initial Cr(III) concentration. Results showed that scale up multiplied by nearly 1.7 the important parameters as critical bed depth and length of unused bed (the same relation that the ratio between length/diameter of pilot-scale column and laboratory-scale column). [ABSTRACT FROM PUBLISHER]

In this work, results of the biosorption of Cr6+and Ni2+by sugarcane bagasse in two up-flow fixed-bed columns in series have been presented. The experimental data were adjusted for several kinetic models that describe the breakthrough curve obtained for a single column and for two columns in series. The Dose–Response model is the one that better adjusts the experimental data for the studied metals with a high correlation coefficient. Although with a single column, it is possible to reduce the metal concentrations under the requirements of Cuban normative, the use of two columns in series guarantees concentration nearly to 0 for two metals. So, the percentage removal with two columns in series were 98.2 and 92.8% for Cr6+and Ni2+, respectively. [ABSTRACT FROM PUBLISHER]

In the present work, biosorption of copper(II) in the presence of lead(II) ions by olive stone and pine bark was investigated in batch and continuous mode. Particularly, it pretends provide new information regarding binary biosorption of metals in continuous flow. The behavior of competitive Cu(II) and Pb(II) biosorption in batch was successfully described by the multicomponent Sips model, obtaining maximum capacities for Cu(II) and Pb(II) of 1.34 and 2.12 mg/g, respectively for olive stone, and 6.05 and 10.04 mg/g, respectively, for pine bark. Olive stone and pine bark removed the target metal ions in the selectivity order of Pb(II)>Cu(II). In continuous mode the biosorption capacity for Pb(II) (6.59 and 26.01 mg/g for olive stone and pine bark, respectively) were also higher than copper one (2.19 and 12.66 mg/g for olive stone and pine bark, respectively), indicating the higher affinity of lead for the two biosorbents in continuous system too. Finally, the results of this study demonstrated that pine bark could be a better biosorbent than olive stone. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 192-204, 2014 [ABSTRACT FROM AUTHOR]

Due to the ever-growing pressure on our planet's natural resources to supply energy, the production of bioethanol by fermentation of lignocellulosic biomass is increasingly important in courses related to engineering and energy. Moreover, recent changes in the teaching–learning paradigm make necessary the introduction of novel teaching tools where students are the protagonist of their education. In this context, the purpose of this study is to compare the results obtained after traditional lessons with those obtained after the implementation of various computer activities based on modeling and simulation of bioreactors to teach biorefinery concepts focused on bioethanol production. Berkeley Madonna was chosen as the digital simulation software package because it is user-friendly, fast, and easy to program. This software allowed students to gain experience writing models that let optimize fermentations in well-stirred bioreactors and others bioprocess of industrial interest. The students (those who participated in the modeling-simulation classes and those who participated in traditional ones) completed a questionnaire and a cognitive test at the end of the course. Students that participated in modeling-simulation classes got a better score than students that participated in traditional classes. Therefore, the study showed the improvement in the understanding of the biorefinery concepts and the students improved their grades. Finally, students' perception about the proposed modeling-simulation learning was also analyzed and they rated the efficiency of this new learning methodology as satisfactory. There are very few studies providing information about educational experiences regarding the development of skills for the formulation, interpretation, simplification, and use of mathematical models based on mass balances and simple microbial kinetics in biochemical engineering courses. The experience described in this work can be used by professors to plan and conduct courses based on the modeling of biochemical engineering problems. [ABSTRACT FROM AUTHOR]