Removal of arsenate, phosphate, and fluoride ions by aluminium-loaded Shirasu-zeolite

A novel adsorbent, aluminium-loaded Shirasu-zeolite P₁ (Al-SZP₁), has been developed for the removal of arsenate, phosphate, and fluoride ions from aqueous system. The dependence of removal percentage upon aluminium concentration in loading solution, pH, initial concentration, and coexisting anions has been investigated. The rate of adsorption of the anions follows first-order reaction, the adsorption mode of each anion is of a Freundlich isothermal nature, and the adsorption mechanism is supposed as an ion-exchange process between these anions and the hydroxide groups on the surface of A1-SZP₁. These anions were also concentrated successfully in a column packed with Al-SZP₁.