| Abstrakt: |
Pollution by dyes is a serious environmental problem. Marine waters receive pollutants from many sources, however, there are few studies that deal with the elimination of pollutants from these environments. The search for effective, cheap, and ecological procedures to remove dyes from seawater is a current challenge. Biosorption meets these requirements, but it is necessary to find the best biosorbent for the operating conditions. Since microalgal biomass is considered a good biosorbent, the efficiency of living biomass from the marine microalga Phaeodactylum tricornutum to remove the Brilliant green dye from seawater was evaluated in this work. This dye showed spontaneous discoloration in seawater, showing a decrease in the amount of dye measured spectrophotometrically but not when measured by HPLC. Consequently, the difference between discoloration and true removal should be considered. It is shown that the determination of the biomass efficiency as biosorbent through spectrophotometric measurements could be wrong in some cases. Batch experiments were performed varying operational parameters, such as initial concentration of dye, contact time, and pH of the solution. At the lowest concentration of the dye (5 mg L-1), the algal biomass (0.4 g L-1) achieved total decolorization and removal (through biosorption) within 7 h, while at the highest concentration (200 mg L-1), discoloration was 96.3%, but removal was 32.6%. The spontaneous discoloration followed a pseudo-second-order kinetics. Pseudo-first-order kinetics and Langmuir isotherm best described the removal process, predicting a maximum biosorption capacity of 161.52±5.95 mg g-1. This natural biomass had a higher efficiency than other more complex biosorbents. [ABSTRACT FROM AUTHOR] |
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