Tea waste as adsorbent for ionic dyes

Abstract

Toxic dyes can be removed from textile effluents and recovered using dead biomass obtained, as waste from the food industry. In this work, tea waste (TW) was employed to assess its adsorptive capacity for the acidic and basic dyes that usually are present in textile industry waste water. Equilibrium and kinetic experiments were performed in batch and column mode. Adsorption equilibrium and fluid solid mass transfer constant data were analyzed through the concept of ion-exchange sorption isotherm. The equilibrium data were fitted with Langmuir and Freundlich models. Several operation variables, such as TW dosage, contact time, initial pH, and temperature, on the removal of dyes were investigated. The removal efficiency increased with increase in TW dosage. The adsorption process followed pseudo-first-order kinetics. Thermodynamic parameters like ΔH°, ΔS°, and ΔG° were analyzed. The processes were spontaneous for the acidic as well as basic dyes. These results suggest that TW is a potential low-cost food industry waste for textile industry waste water treatment. TW was characterized using Scanning electron micrograph and Fourier transform infrared spectroscopy and techniques.

Keywords:

• Tea waste
• Biosorption
• Kinetics
• Thermodynamics
• Column operation
• Acidic and basic dye