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Synthesis and application of a new carboxylated cellulose derivative. Part I: Removal of Co2+, Cu2+ and Ni2+ from monocomponent spiked aqueous solution

Teodoro, Filipe Simões, Ramos, Stela Nhandeyara do Carmo, Elias, Megg Madonyk Cota, Mageste, Aparecida Barbosa, Ferreira, Gabriel Max Dias, da Silva, Luis Henrique Mendes, Gil, Laurent Frédéric, Gurgel, Leandro Vinícius Alves
Journal of colloid and interface science 2016 v.483 pp. 185-200
Fourier transform infrared spectroscopy, X-ray diffraction, adsorbents, adsorption, anhydrides, aqueous solutions, calorimetry, carboxylation, carboxylic acids, cellulose, cobalt, copper, desorption, energy-dispersive X-ray analysis, esterification, metal ions, models, nickel, nuclear magnetic resonance spectroscopy, pH, porosity, scanning electron microscopy, sorption isotherms, surface area, thermogravimetry, titration, weight gain
A new carboxylated cellulose derivative (CTA) was prepared from the esterification of cellulose with 1,2,4-Benzenetricarboxylic anhydride. CTA was characterized by percent weight gain (pwg), amount of carboxylic acid groups (nCOOH), elemental analysis, FTIR, TGA, solid-state ¹³C NMR, X-ray diffraction (DRX), specific surface area, pore size distribution, SEM and EDX. The best CTA synthesis condition yielded a pwg and nCOOH of 94.5% and 6.81mmolg⁻¹, respectively. CTA was used as an adsorbent material to remove Co²⁺, Cu²⁺ and Ni²⁺ from monocomponent spiked aqueous solution. Adsorption studies were developed as a function of the solution pH, contact time and initial adsorbate concentration. Langmuir model better fitted the experimental adsorption data and the maximum adsorption capacities estimated by this model were 0.749, 1.487 and 1.001mmolg⁻¹ for Co²⁺, Cu²⁺ and Ni²⁺, respectively. The adsorption mechanism was investigated by using isothermal titration calorimetry. The values of ΔadsH° were in the range from 5.36 to 8.09kJmol⁻¹, suggesting that the mechanism controlling the phenomenon is physisorption. Desorption and re-adsorption studies were also performed. Desorption and re-adsorption efficiencies were closer to 100%, allowing the recovery of both metal ions and CTA adsorbent.