Potential of Lemna minor and Eichhornia crassipes for the phytoremediation of water contaminated with Nickel (II).

Phytoextraction of Nickel (II) in water by two types of aquatic macrophytes (Lemna minor and Eichhornia crassipes) was investigated using synthetic aqueous solutions of NiSO4 at concentrations of 0.5, 1.5 and 2.5 mg/L. The toxic effects of nickel salt in plants were evaluated through the presence of necrosis and chlorosis. The bioconcentration factor, Nickel (II) removal efficiency and kinetics of removal were also calculated. Results of this study show bioconcentration factors higher than 1000, which categorize L. minor and E. crassipes as hyperaccumulators. Besides, L. minor presented a removal percentage higher than 68%, compared to E. crassipes that did not exceed 50% in any of the three concentrations studied. However, E. crassipes showed better resistance to the effects of nickel and obtained a greater removal capacity during the phytoremediation process that lasted for 10 days. In contrast, L. minor suffered necrosis and chlorosis in a concentration-dependent way. Consequently, both macrophytes are sustainable alternatives for nickel removal from contaminated water.

ESTUDIO DE MODIFICACIÓN QUÍMICA Y FÍSICA DE BIOMASA (Citrus sinensis Y Musa paradisiaca) PARA LA ADSORCIÓN DE METALES PESADOS EN SOLUCIÓN / STUDY OF PHYSICAL AND CHEMICAL MODIFICATION OF BIOMASS (Citrus sinensis AND Musa paradisiaca) FOR THE ADSORPTION OF HEAVY METALS IN SOLUTION

Se estudia el efecto de las modificaciones a carbón activado y recubrimiento con quitosano de biomasa lignocelulósica obtenida de cáscaras de plátano y naranja, para la adsorción de Cr (VI). La caracterización de los grupos funcionales en las biomasas aptos para la adsorción se verificó mediante un análisis elemental (CHON) y espectroscopia de infrarrojo (IR), mientras que para los carbones activados se determinó su área superficial por medio de un análisis BET. El contenido de Cr (VI) en solución se midió mediante espectrofotometría UV-vis, usando el método de la difenilcarbazida. Los resultados mostraron una remoción de los iones de Cr (VI) de 66,6 y 93 ppm para las cáscaras de naranja y plátano respectivamente, los carbones activados removieron 85 y 95 ppm, mientras que las biomasas modificadas con quitosano presentaron una adsorción 61,24 y 88,2 ppm. Se observa que la cinética de adsorción fue mejor descrita por la ecuación de Pseudo Segundo Orden, y el efecto de competitividad bimetálica se vio afectada de mayor forma por iones de níquel, y en menor proporción por iones de plomo.

The effect of changes to activated charcoal and chitosan coating of lignocellulosic biomass obtained from banana and orange peels for the absorption of Cr (VI) was studied. Characterization of the functional groups in the biomass suitable for the adsorption was monitored by elemental analysis (CHON) and infrared spectroscopy (IR), while for activated carbon surface area was determined by BET analysis. The Cr (VI) content in solution was measured by UV-vis spectrophotometer, using the diphenylcarbazide method. The results showed a removal of Cr (VI) ions of 66.6 and 93 ppm for orange peels and banana peels respectively; the activated carbons removed 85 and 95 ppm, while the modified biomasses with chitosan showed an adsorption of 61.24 and 88.2 ppm. It was observed that the adsorption kinetics was best described by the Pseudo Second Order equation, and the bimetallic competitiveness effect was affected more by nickel ions and to a lesser extent by lead ions.