Adsorption of phosphate onto pumice powder.

The adsorption of phosphate onto pumice powder was studied as a function of time, pH and total dissolved phosphate concentration. Phosphate removal efficiency was found to be more than 80%. The adsorption reaction was considered to be a reversible reaction at which a forward first order reaction is opposed by a second order reaction. The reaction rate constant k was calculated as 28.31 ± 2.37×10-3. Phosphate adsorption data had a good fit to Freundlich adsorption isotherm at pH 3, 5, 7 and 9. In the presence of NaCl, Na2SO4, MgClg, CaCl2, NaF and urea, the adsorption was slightly affected.