Adsorption of
phosphate and fluoride from fertilizer industry effluent using fly ash and chitosan
nano-adsorbents
Soman Sabitha, Madhu G., Jayachandran K. and Lila Bhai T.S.
Res. J. Chem. Environ.; Vol. 29(9); 164-173;
doi: https://doi.org/10.25303/299rjce1640173; (2025)
Abstract
The waste water generated from a chemical fertilizer industry contains different
organic and inorganic pollutants. The adoption of low-cost, easily available materials
in effluent treatment has recently attracted huge interest. The present study used
fly ash and chitosan, modified with titanium dioxide, for the adsorption of phosphate
and fluoride from fertilizer industry effluent. Batch adsorption experiments were
conducted in the laboratory in order to evaluate the phosphate and fluoride removal
efficiency of modified fly ash and chitosan. The adsorption of phosphate and fluoride
onto fly ash and chitosan nano-composites as a function of initial ion concentration,
adsorbent dosage, contact time and solution pH was investigated for optimization.
The adsorbents were characterized by X-ray diffraction and FTIR spectroscopy. Fly
ash and chitosan nano-composites showed a removal efficiency of above 90% for phosphate
from the effluent sample and the maximum adsorption was at acidic pH. Fly ash removed
60% of the fluoride, whereas chitosan removed fluoride with an efficiency of more
than 80%. Effective fluoride adsorption occurs in the pH range of 4–6 and decreases
with an increase in pH. The sorption data were represented using Freundlich and
Langmuir isotherm models, where the data were best filled by Freundlich isotherm
model.
