Fracionamento de surfactina em coluna de bolhas e espuma / Fractionation of surfactin on a bubble and foam column

AUTOR(ES)
DATA DE PUBLICAÇÃO

2010

RESUMO

Foam fractionation of biosurfactant surfactin solutions obtained from fermentation with Bacillus subtilis bacteria was experimentally studied. A bubble and foam column system was mounted and operated in a semi-batch mode aiming at to optimize the concentration enrichment and the recovery of the bioproduct. The process involves the injection of gaseous nitrogen through a sparger in the basis of the column containing the surfactin liquid solutions. Gas flow rates of 20, 40 and 60 mL/min and initial concentrations of 240, 400 and 700 mg/L were used in the experimental runs. Temperatures of 15, 25 and 35 °C were used in the experiments. With the bubbles ascending in the column, a convection phenomena is produced from the liquid to the gas and due the amphiphilic property of the surfactant, solute molecules are adsorbed at the gas-liquid interface of the bubbles. A foam column on the top of the liquid column is also formed and after drainage phenomena and a break procedure of the foam, a surfactant concentrated solution is obtained. Surfactin enrichment and recovery from the initial solution were determined for several experimental conditions. Average values for the enrichment are in the range of 1,9 to 52,5 times and recovery are in the range from 80,5 to 98,3 %. The higher values of enrichment are got with diluted solutions runs operated at low gas flow rates and higher temperatures. The results indicates this process as very promising in the concentration of surfactin solutions. Using Gibbs adsorption theory for the gas-liquid interface, gas-liquid isotherms were obtained in the temperatures of 15, 25 and 35 °C and adjusted by the Langmuir model. A variance analysis from experimental planning was performed and showed a good agreement with experimental results. A mathematical modeling for the convection, adsorption and equilibrium represented satisfactorily the depletion curves in the bubble column

ASSUNTO(S)

separation (technology) foam biosurfactantes separação (tecnologia) bacillus subtilis biosurfactants espuma bacillus subtilis

ACESSO AO ARTIGO

Documentos Relacionados