Synthesized Goethite and Natural Iron Oxide as Effective Absorbents for Simultaneous Removal of Co(II) and Ni(II) Ions from Water

Abstract

This study reports on the adsorption efficiency of a natural iron oxide from Mballam-Cameroon in comparison with synthesized goethite to simultaneously remove cobalt and nickel ions from aqueous solutions. Chemical analysis on the natural iron oxide sample revealed iron as the main element and hematite (58.52%) goethite (19.42%), kaolinite (12.69%) and quartz (7.79%) as the component phases in the iron oxide sample. The iron oxide was found to be microporous (BET surface area 43.27 m 2 /g) with fairly spherical polydisperse particles. Results show maximum absorption for Co(II) and Ni(II) ions for both adsorbents occurred at an equilibrium contact time of 80 mins, dose rate of 0.1 g/L, and pH = 7. Goethite was slightly more efficient at removing target metal ions with maximal adsorbed quantities at 117.8 mg/g of Co(II) and 100.6 mg/g of Ni(II), and 103.9 mg/g of Co(II) and 85.2 mg/g of Ni(II) ions for natural iron oxide. Equilibrium modelling presented the Freundlich isotherm as the best fit model for both adsorbents and metal ions, indicating heterogeneity of the surface binding sites during adsorption. The pseudo-second order kinetic model was the best-fit model, indicating chemical adsorption between the adsorbent surface and metal ions, hence a good correlation between equilibrium and kinetics. The findings indicate that the efficacy of the natural iron oxide from Mballam is almost equivalent to that of synthetic goethite, validating its applicability for the simultaneous removal of cobalt and nickel ions from aqueous solution.

Degradación del colorante textil azo azul reactivo 69 (lanasol) por fotocatálisis heterogénea

“…En figura 18 se muestran los espectros de los fotocatalizadores sintetizados a partir de sulfato ferroso, se observa que todos los fotocatalizadores presentan bandas de absorción alrededor de 3400 y 3134 cm -1 , además de las bandas 1649, 1644, 1634 y 1636 cm -1 , respectivamente se asocian a los modos de estiramiento de moléculas de agua y/o grupo hidróxido residual [94]. Las bandas en 1437 cm -1 se asocian a varios modos vibracionales NH4 + del agente precipitante debido a la imposibilidad de su remoción, aún a altas temperaturas [90].…”