Resumen

ALE BORJA, Neptalí et al. Equilibrium of lead (II) biosorption and characterization through FT-IR and SEM-EDAX on Ascophyllum Nodosum seaweed. Rev. Soc. Quím. Perú [online]. 2015, vol.81, n.3, pp.242-253. ISSN 1810-634X.

Lead (II) biosorption on Ascophyllum nodosum seaweed at 20°C and initial pH 4-5 was studied, by using models of Langmuir and Freundlich isotherms. In order to establish seaweed, CaCl₂ was used. The granulometry used in the biosorbent was 0-75 µm. In Fourier transform infrared spectroscopy, FT-IR, a shift in the signal of carbonyl group of crosslinked sample before metal biosorption and after (1600.92 cm^-1 to 1573.91 cm^-1) and 1400 cm^-1 (that was from 1415.75 cm^-1 to 1409.96 cm^-1) was observed, suggesting a chelating (bidentate) character of the metal biosorption onto carboxylic groups that belongs to the units of alginate monomeric. The bands at 3305.99 cm^-1 allowed the recognition of hydroxyl groups in the biosorbent. The scanning electronic microscopy, SEM, verified heterogeneity of biosorbent particles. In the energy-dispersive X-ray spectroscopy, EDAX, a very strong signal in the carbon and another less strong for the oxygen characteristic of the biopolymer were observed. The signal of calcium could be recognized in EDAX spectra of the sample after pre-treated. The two peaks that correspond to lead element were observed in the sample after biosorption process. Experimental data of biosorption equilibrium had greater correlation coefficient to Langmuir isotherm model, reaching the maximum sorption capacity, q_max, of 228 mg/g. Lead (II) residual concentration, C_eq, in the solutions after getting equilibrium, was determined after 72h starting the process by atomic absorption spectroscopy. For data processing and statistic treatment, Origin 6.0 informatics program was used.

Palabras clave : Biosorption; Ascophyllum nodosum; lead; isotherm; Langmuir; Freundlich.

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