Abstract

VIZCAINO MENDOZA, Lissette; FUENTES MOLINA, Natalia  and  GONZALEZ FRAGOZO, Harold. ADSORPTION OF LEAD (II) WITH STEMS AND LEAVES OF Eichhornia crassipes IN AQUEOUS SOLUTION. rev.udcaactual.divulg.cient. [online]. 2017, vol.20, n.2, pp.435-444. ISSN 0123-4226.

The presence of heavy metals such as lead (Pb⁺²) in water bodies causes alterations in environmental quality and public health due to their solubility and capacity of accumulation in the food chain. Problems that can be increased by the accumulation of Eichhornia crassipes an aquatic weed with high invasive capacity whose presence in the aquatic ecosystems favors the processes of eutrophication and growth of pathogenic microorganisms vectors of diseases. As an alternative for the removal of heavy metals and the use of TEC stems and HEC leaves of E. crassipes, the adsorption capacity and removal efficiency of Pb⁺² in aqueous solution of this biomass were evaluated. Initially batch tests were performed to analyze the influence of the adsorbent dose, contact time and solution pH. As final disposal method, the calcination was analyzed at temperatures of 700 and 800°C. The equilibrium experimental data were correlated using the Langmuir and Freundlich models. The best fit model was the Langmuir model with R²=0.9816 TEC and R²=0.9854 HEC, achieving a maximum adsorption capacity of 172.41mg/g TEC and 131.58mg/g HEC with 0.2 g Of biomass/200mL, pH 5.5 and 3h of contact. Pb⁺² removals above 97% were achieved in all tests. Calcination tests indicate that at temperatures ≥800°C it is possible to stabilize the residual biomass by preventing the removed metal cations from being released from the biological matrix by the effects of low pH leaching solutions.

Keywords : Biosorption; water buffer; Langmuir isotherms; Freundlich isotherms; heavy metals.

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