Abstract

PINEDA-AYALA, David Moisés  and  DURAN-HERRERA, José Esteban. Evaluation of oil palm empty fruit bunch wastes as adsorbent for the removal of reactive dyes from aqueous solutions. Ing. invest. y tecnol. [online]. 2019, vol.20, n.1. ISSN 2594-0732.  https://doi.org/10.22201/fi.25940732e.2019.20n1.008.

In this research, oil palm empty fruit bunch (OPEFB) wastes (Elaeis guineensis) were evaluated as potential adsorbent material of reactive dyes in wastewaters. Reactive dyes yellow 254 (RY254), orange 122 (RO122) and black 5 (RB5) were used as model contaminant dyes. OPEFB evaluation was performed with and without chemical pre-treatment (NaOH hydrolysis and water-only washing) and under different operating conditions (pH, adsorbent-adsorbate ratio, and initial concentration of dye). Additionally, the isoelectric points of the dyes and the zero charge point of the adsorbent were determined. It was found that best adsorption occurs when OPEFB is just washed with boiling water as pre-treatment. The operating conditions that favored the adsorption capacity were pH=3, dye concentration of 20 mg/L and OPEFB concentration of 0.5 g per 100 mL of treated solution; under these conditions, adsorption capacities of 2.4-3.3 mg/g and dye removal of 60-85% were obtained. The isoelectric points obtained for RY254, RO122 and RB5 dyes were 5.88, 5.92 and 6.45, respectively. The point of zero charge of OPEFB was estimated at pH=6.1. The OPEFB adsorption capacity is considerably reduced at neutral pH values (particularly between 5.8 and 6.5) due to the coincidence of the isoelectric points of the reactive dyes studied and the zero-charge potential of the OPEFB in that range. From this study it is concluded that OPEFB has good characteristics to be used as an adsorbent material for textile dyes.

Keywords : Adsorption; reactive dyes; oil palm empty fruit bunch; contamination; water purification.

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