Removal of Nitrite Ions from Aqueous Solutions by Ethylenediamine Polysiloxane Immobilized Ligand System

Abstract

The functionalized porous solid ethylenediamine polysiloxane immobilized ligand system P-NN (where P represents [Si-O]n polysiloxane network and NN represents ethylenediamnie  group) was prepared by hydrolytic polycondensation of 3-aminopropyl-2-aminoethyltrimethoxysilane with tetraethylorthosilcate (TEOS) in the presence of CTAB surfactant. CTAB was used to enhance the porosity of the material and therefore increases the adsorption capacity of the immobilized ligand system. The functionalized ligand system was investigated as adsorbent for nitrite ions from aqueous solutions. Both batch and column methods were carried out and the effect of various parameters was studied that include contact time, pH, nitrite concentration and temperature in order to investigate the optimum conditions for the nitrite ions removal.  The optimum nitrite adsorption was established in acidic medium, at 75oC, and at contact time equals 24 h. The nitrite removal was about 65-100% at 5-50 ppm of initial nitrite concentration. The use of this adsorbent is proved to be repeatable and recyclable. The adsorbent can be considered as a promising material for nitrite removal from different water and waste water and aqueous extracts containing nitrite ions.