Dynamic Cr(III) uptake by Macrocystis pyrifera and Undaria pinnatifida biomasses

PLAZA CAZÓN JOSEFINA; VIERA MARISA; DONATI EDGARDO

ELECTRONIC JOURNAL OF BIOTECHNOLOGY

UNIV CATOLICA DE VALPARAISO

Lugar: Valparaíso; Año: 2012 vol. 16

0717-3458

Abstract Background: The increased industrial activity has resulted in the discharge of large volume of pollutants including non-degradable metals into the environment. Chromium is produced in several industrial processes and it can be found in the environment in two stable oxidation states, Cr(VI) and Cr(III). Cr(VI) is more hazardous due to its carcinogenic and mutagenic effects on living organisms. Although much less toxic, Cr(III) can also exert genotoxic effects under prolonged or high exposure. It can be separated from the solution by precipitation but biosorption using brown algae seems to be an effective and sustainable treatment technique owing to its cost-effectiveness and environmental friendly characteristics. Macrocystis pyrifera and Undaria pinnatifida are two marine brown macroalgae with high capability of removing heavy metals including Cr(III) in batch studies. In this work Cr(III) biosorption in a fixed bed columns filled using M. pyrifera and U. pinnatifida biomasses was evaluated. Results: The shapes of the breakthrough curves were quiet different for each biomaterial. Parameters like the breakthrough time (tb) and zone mass transfer (MTZ) showed that U. pinnatifida has greater affinity for Cr(III). The maximum adsorption capacity at the saturation time (ts) demonstrated that M. pyrifera has higher retention for Cr(III). The experimental data were used to fit different mathematical models as Thomas, Yoon-Nelson and Dose-Response models. The best correlation coefficient (0.94 or 0.96) was obtained with Dose-Response model so this model can predict the behaviour of the Cr(III) uptake under different experimental conditions. Conclusions: M. pyrifera and U.pinnatifida are efficient biosorbents for Cr(III) adsorption under a continuous mode of operation although the differences observed in the capacity and the affinity suggest different mechanisms involved.