Biosorption of synthetic dyes from textile industrial effluent using waste papaya latex

Abstract

Aim: The effect of pH, adsorbent concentration, time, initial dye concentration and agitation speed on adsorption capacity of papaya latex as an adsorbent was investigated. Methodology: The biosorption experiments were carried out in batch process by means of conical flask and agitated in a thermostated shaking incubator at rpm for a suitable contact time at different temperature range. The experiments were carried out at different pH (4-9), fixed biosorbent dosage, temperature, contact time, initial dye concentration and agitation speed. The samples were withdrawn at regular intervals and the concentration of dyes were analyzed using a UV- Visible spectrometer. Results: The adsorption studies revealed that papaya latex removed about 83.18% of the reactive red dye and 87.97% of deep marine blue dye from aqueous phase under optimal conditions. The maximum adsorption of both dyes was found at pH 4. Adsorption isotherms such as Langmuir, Freundlich, Temkin and Dubin models were attempted to predict equilibrium data. The pseudo-first-order kinetics provide the best correlation of experimental data. Interpretation: Waste papaya latex can be used as an eco-friendly and low-cost adsorbent in removal of reactive red dye and deep marine blue from textile effluent.