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RESUMEN El aprovechamiento de desechos vegetales para la obtención de carbón activado se ha empleado en los últimos años para la remoción de contaminantes metálicos pesados en aguas. Por ello, este estudio presenta la obtención de carbón activado a partir de cáscara de naranja (CACN) reciclada, sintetizado por dos procesos de activación y luego tratamiento térmico, para la remoción de iones cadmio, Cd(II), debido a su toxicidad alta. Las caracterizaciones por espectroscopía Raman y FTIR, indicaron la presencia de los grupos funcionales característicos del carbón. La evaluación del área superficial calculada por el método BET (Brunauer- Emmett-Teller), arrojó un área superficial específica de 154,96 m2.g-1 y una distribución de tamaño de poro de 6,70 nm y 12,39 nm calculada por el método de BJH (Barrett-Joyner- Halenda). El proceso de remoción en diferentes electrólitos soportes, se evaluó por el método electroquímico de voltamperometría de onda cuadrada (VOC), obteniéndose como electrólito óptimo para la remoción 0,1 mol.L-1 HCl. Además, el estudio del proceso cinético llevado a cabo en un tiempo de 6 horas, alcanzó una capacidad de remoción (qe) de Cd(II) de 7,52 g.g-1 y un porcentaje de remoción (%R) de 60%. Este estudio establece que el proceso de adsorción del Cd(II) por el CACN, sigue un modelo de pseudo primer orden, representado por Log(qmax - qt) = 0,94 - 0,0024t con r2 = 0,9134. ABSTRACT The use of vegetable waste to obtain activated carbon has been used in recent years for the removal of heavy metal contaminants in water. For this reason, this study presents the obtaining of activated carbon from recycled orange peel (OPAC), synthesized by two activation processes and then thermal treatment, for the removal of cadmium ions, Cd(II), due to its high toxicity. Characterizations by Raman and FT-IR spectroscopy indicated the presence of characteristic functional groups of carbon. The evaluation of the surface area calculated by the BET (Brunauer-Emmett-Teller) method, yielded a specific surface area of 154,96 m2.g-1 and a pore size distribution of 6,70 nm and 12,39 nm calculated by the BJH method (Barrett-Joyner-Halenda). The removal process in different supporting electrolytes was evaluated by the electrochemical method of square wave voltammetry (SWV), obtaining 0,1 mol.L-1 HCl as the optimal electrolyte for removal. In addition, the study of the kinetic process carried out in a time of 6 hours, reached a removal capacity (qe) of Cd(II) of 7,52 g.g-1 and a removal percentage (%R) of 60%. This study establishes that the Cd(II) adsorption process by OPAC follows a pseudo first order model, represented by Log(qmax - qt) = 0,94 - 0,0024t with r2 = 0,9134.

In this study, composite polymeric cryogel cartridges were achieved by using Cd(II) imprinted poly(hydroxyethyl methacrylate N-methacryloly-(L)-cysteine methylester) beads and poly(hydroxyethyl methacrylate) cryogel cartridges with two different mole ratios of functional monomer. The N-methacryloly-(L)-cysteinemethylester was used as a functional monomer and Cd(II) 1:1 and 2:1, which were then notated as MIP1 and MIP2, respectively. Various characterization methods have confirmed the structural transformation on the MIP1 and MIP2 composite cryogel cartridges by scanning electron microscopy, Fourier-transform infrared spectroscopy-Attenuated Total Reflectance, and swelling tests. The maximum amount of Cd(II) adsorption with composite cryogel cartridges was determined by altering the Cd(II) initial concentration, temperature, and pH values. The maximum adsorption capacity of MIP1 and MIP2 composite cryogel cartridges obtained was 76.35 and 98.8 &micro, mol/g of composite cryogels, respectively. The adsorption studies revealed that the MIP2 possessed a good adsorption performance for Cd(II). The obtained composite cryogel cartridges have a selective, reusable, and cost-friendly potential for the removal of Cd(II) from aqueous solutions, and are used many times without decreasing their adsorption capacities significantly. The Cd(II) removal rate of the MIP1 and MIP2 composite cryogel cartridges from synthetic wastewater samples was determined as 98.8%. The obtained cryogel cartridges&rsquo, adsorption material exhibited a good directional removal performance for Cd(II) from wastewater samples.

In this study, Cd (II) ion was determined using a cyclodextrin-based polymeric fluorescence sensor prepared by UV-curing technique. The effects of several parameters such as pH, time, coexisting ions on the fluorescence intensity were also examined. The excitation and emission wavelengths were found to be 374 nm and 422 nm, respectively. The measurement range was in the range of 4.45x10 -9 mol L -1 to 4.45x10 -8 mol L -1 for Cd(II) ions and the detection limit was calculated as 6.23 ´ 10 -10 mol L -1 . In addition, sensor membrane was selective which was not influenced by common coexisting metal ions. The concentrations of the foreign ions such as Pb(II), Co(III), Ag(I), Zn(II), Cu(II), Cr(III) are 1000-fold higher than Cd(II) ions. Besides the prepared polymeric fluorescence sensor was successfully implemented to the determination of Cd(II)ions in biscuit and tap water samples.