Removal of Boron by Surfactant Modified Zeolitic Tuff from Northeastern Greece

Abstract

Boron adsorption on surfactant modified zeolite (SMZ) was investigated, in the perspective of using SMZ for B removal from irrigation waters, since SMZ has been proven efficient adsorbent for many anions. A calcareous clinoptilolite was used and a sub-sample was treated with HCl. Then the charge of the external surface of the untreated and treated zeolite was modified and B adsorption was studied. The SMZ adsorbed B and its adsorption capacity was increased with HCl treatment and pH adjustment at the strongly alkaline range. However, in all cases the relative amounts of B removed from solution were much lower than other anions reported in the literature. In addition, B concentration in the equilibrium solution was above 3 mg L-1, which is considered a critical limit for B in irrigation waters in respect to the risk of B phytotoxicity. It was concluded that SMZ is not an effective means for B removal from irrigation waters and thus its use for B water treatment is not recommended.