Resumo

SANCHEZ SANCHEZ, Deysi et al. Kinetics study of cadmium (II) biosorption on crosslinked pectin from orange peels. Rev. Soc. Quím. Perú [online]. 2014, vol.80, n.4, pp.298-307. ISSN 1810-634X.

Biosorption kinetics of cadmium (II) on cross-linked pectin extracted from orange peels at 20°C was studied, obtaining an equilibrium sorption capacity, q_e, of 99.56 mg/g in pH range 4.5-5.5. Pectic material was extracted through acid hydrolysis (pH: 1.5, temperature: 90°C, time: 30 min) and crosslinked with formaldehyde acidic solution in order to diminish hydration capacity and swelling, as well as polysaccharide leaching when found in aqueous environment. Biosorption kinetics experimental data showed greater coefficients of correlation (R²) on pseudo second order mathematic model. Physical chemistry parameters: particle size influence (125 μm - 500 μm and 0 μm - 125 μm) and biosorbent and metal concentrations in solution were evaluated in the biosorption kinetics. Pseudo second order constant, k₂ = 8.0x10^-4 g.mg^-1min^-1, of biosorbent with particle size 125-500 μm increased in 13.7% as particle size decreased to 0-125 μm, meanwhile, q_e increased from 140.7 to 148.4 mg/g at the same conditions. Lead (II) residual concentrations in solution were determined by atomic absorption spectroscopy. For data processing and statistic treatment of non-linear regression, Origin 6.0 informatics program was used.

Palavras-chave : Biosorption; pectin; cadmium; kinetic; pseudo-first order; pseudo-second order.

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