CAPACIDAD ADSORTIVA DEL CARBÓN ACTIVADO OBTENIDO DEL EPICARPIO DE Citrus sinensis EN LA REMOCIÓN DE INDIGOTINA

  La industria textil genera efluentes altamente coloreados y constituidos por compuestos difícilmente biodegradables. En esta investigación se evaluó la capacidad adsortiva del carbón activado preparado a partir del epicarpio de Citrus sinensis en la remoción del colorante azul índigo (indigotina). El carbón se obtuvo mediante un proceso de activación química del precursor con H3PO4 al 40% durante 1 h. Posteriormente, se caracterizó por medio de los parámetros: densidad aparente, humedad, cenizas e índice de yodo. Se comparó la capacidad adsortiva del carbón de Citrus sinensis (CACN) con un carbón comercial (CAC), mediante la realización de ensayos por carga. El carbón activado preparado a partir de las cáscaras de naranja presentó una densidad aparente de 0,459 g/mL, lo que indica que puede ser utilizado en procesos de adsorción por carga debido a su alta resistencia mecánica. Los resultados del proceso de adsorción se ajustaron mejor al modelo de Freundlich, ya que existió una mejor linealidad y una menor dispersión de los datos experimentales; así como bajos valores de la suma de los cuadrados de los errores relativos. Se obtuvieron porcentajes de remoción de indigotina para el carbón activado de cáscaras de naranja y el carbón activado comercial de 70,35% y 88,78%, con dosis óptimas de 8 y 2 g/L tratando aguas sintéticas con concentraciones iniciales de 67 y 37 mg indigotina/L, respectivamente, lo que indica que estos materiales adsorbentes pueden de ser empleados en el tratamiento de efluentes textiles para la reducción del azul índigo.   Palabras clave: adsorción, carbón activado, cáscaras de naranja, indigotina.   Abstract The textile industry generates highly colored effluents made up of hardly biodegradable compounds. The adsorptive capacity of activated carbon prepared from the epicarp of Citrus sinensis in the removal of indigo blue dye (indigotine) was evaluated in this research. The carbon was obtained through a process of chemical activation of the precursor with H3PO4 (40%) during one hour. The activated carbon obtained was characterized by the parameters: density, humidity, ash and iodine index. The adsorptive capacity of Citrus sinensis carbon (CACN) with a commercial carbon (CAC) was compared by carrying out batch tests. Activated carbon prepared from orange peels presented an apparent density of 0.459 g/mL, which indicates that it can be used in charge adsorption processes due to its high mechanical resistance. The results of the adsorption process were better adjusted to the Freundlich model, given the better linearity and a smaller dispersion of the experimental data; as well as low values of the sum of the squares of the relative errors. Indigotine removal percentages were obtained for activated charcoal from orange peel and commercial activated carbon of 70.35 % and 88.7 8%, with optimal doses of 8 and 2 g/L treating synthetic waters with initial concentrations of 67 and 37 mg indigotine/L, respectively, which indicates that these adsorbent materials can be used in the treatment of textile effluents for the reduction of indigo blue.   Keywords: physicochemical treatment, coagulation, industrial wastewater, effluent, bentonite, ferric chloride, aluminum sulfate. &nbsp

Adsorption and degradation of rhodamine B and bromocresol green by FeOCl under advanced oxidation process

FeOCl has gained popularity as a heterogeneous catalyst for pollutant removal in the Fenton process. However, humidification and adsorption of FeOCl are usually not considered in the process. In this way, the adsorption and Fenton activity using rhodamine B (RhB, cationic compound) and bromocresol green (BCG, anionic compound) as pollutants models, at various pH were studied (2, 3.6, 7, and 10). These studies show a very low adsorption level for RhB only at pH 10; therefore, the removal was due to the Fenton reaction. For BCG, at pH 10 the adsorption is almost zero, and at pH 7 after 240 min the adsorption was almost complete, at pH 7, the dye removal by adsorption is akin to Fenton, therefore, at this pH, the remotion was entirely attributed to adsorption. The solution’s removal is the result of the adsorption and Fenton reaction. Additionally, the photocatalytic and photo-Fenton activity of FeOCl was studied by the removal of RhB from a solution at pH 3.6, removing about 84 and 95% of the dye respectively. Under these circumstances, FeOCl is a potential catalyst that could be used for Fenton, photo-Fenton, and photocatalysis. However, the present paper’s experimental data shows that its activity depends largely on the percentage of humidity in the catalyst and the ionic charge of the contaminant that will be treated by the catalyst once it has been activated by water vapor. Characterization essays, such as XRD, show a match for the synthesized FeOCl and FT-IR shows a peak change in the -OH groups range. This could be a possible explanation for the apparition of free radicals