42 research outputs found
Adsorptive removal of textile reactive dye using Posidonia oceanica (L.) fibrous biomass
The Mediterranean seagrass Posidonia oceanica (L.) leaf sheaths were
used as low cost, available and renewable biological adsorbent for the
removal of reactive textile dye from aqueous solutions. Batch
experiments were carried out for sorption kinetics and isotherms.
Operating variables studied were temperature, pH and chemical
pretreatment. Biosorption capacity seems to be enhanced by increasing
the temperature. Maximum colour removal was observed at pH 5.
Pre-treating fibres with H3PO4 and HNO3 solutions increased the
adsorption efficiency up to 80 %. Experimental sorption kinetic data
were fitted to both Lagergren first-order and pseudo-second-order
models and the data were found to follow first-order equation for raw
fibres and pseudo-second-order for pre-treated ones. Equilibrium data
were well represented by the Freundlich isotherm model for all tested
adsorption systems. Besides, the thermodynamic study has showed that
the dye adsorption phenomenon onto P. oceanica biomass was favourable,
endothermic and spontaneous
Biosorption of metal dye from aqueous solution onto Agave americna (L.) fibres
In this research, a new low cost and abundant biosorbent; Agave
americna (L.) fibres has been investigated in order to remove metal
dye (Alpacide yellow) from aqueous solutions. In order to optimize the
biosorption process, the effect of pH, temperature, contact time and
initial solution concentration was investigated in batch system. The
results indicated that acidic pH=2 was favourable for metal dye
removal. The increase of temperature increases the velocity of the
biosorption reaction. The biosorption kinetics of alpacide yellow were
closer to the pseudo-second order than to the first order model for all
concentrations and temperature. The calculated thermodynamic parameters
such as ΔG0, ΔH0 and ΔS0 indicated a spontaneous and
endothermic biosorption process of metal dye onto Agave americana
fibres. The equilibrium data were analysed using the Langmuir and
Freundlich isotherms and showed a good fit with Langmuir model at lower
temperatures and with Freundlich model at 50 °C