Application of Activated Carbon Prepared from Nypa Palm Seed Husk in the Adsorption of Azo Dyes from Waste Water and Evaluation of the Adsorption Isotherms

Abstract

Nypa palm seed husk is an underutilized raw material found in Niger Delta region of Nigeria. In this research, this material was utilized as a raw material for the production of activated carbon which was used as an absorbent for the treatment of simulated wastewater containing Congo red (CR) and Methyl red (MR) (azo dyes). The effect of adsorbate concentration, absorbent dosage, adsorbent-adsorbate contact time on the adsorption of these dyes were evaluated. The results revealed that the adsorption efficiency of MR increase from 20.45 – 91.27 % and that of the CR increase from 68.50 – 99.83 % when the amount of adsorbent was increased from 0.1 – 0.5 g. When adsorbent-adsorbate contact time was increased from 30 – 150 min, the adsorption efficiency increases from 20.93 – 98.94 % for MR and 58.33 – 94.83 % for CR. Also increase in the adsorbate concentration from 50 – 250 mg/L resulted in the decrease in the adsorption efficiency, from 93.16 – 76.10 % for MR and 87.68 – 73.01 mg/L for CR. Adsorption mechanism of these dyes were determined using Langmuir and Freundlich isotherms. From the values of the linear regression coefficient R2, it was found that the adsorption of methyl red followed Freundlich isotherm while the adsorption of Congo red followed Langmuir isotherm. Hence, Nypa palm seed husk which is presently discarded as a waste material can be utilized in the preparation of activated carbon and apply in the adsorption of azo dyes from industrial effluents.