Competitive Adsorption of Metal Pollutants on Modified Silica gel

Today, absorbents have the most important role in chemical refinement of industrial Swages. Silica gels provides an excellent surface for preconcentration of various materials including metals from aqueous systems. Silica gels can be modified chemically using organic precursors producing organically modified silica. In this work we considered competitive adsorption on modified silica between 6 intermediate and an alkaline metal, to know which one of them will be in lower concentration in primal applied solution. At first step silica gel was chemically activated then its surface was modified using 3- chloro propyle three methoxy silane, after washing with toluene and letting it to dry, it was reactionized with 2- amino thio phenol to produce the solid product 2- amino thio phenol, attached to Silica chloropropyle (AMPTMS) [1].We used this adsorbent for comparing absorption of different metals in binary metal aqueous solutions. Appearing new absorption bands in AMPTMS spectrum compared to other materials that we have used shows producing of a new and more complicated absorbant.in figure 2. Absorption band in 521.43cm-1 is belonged to C-S stretching, strong bands in 2818.08 cm-1 & 2883.82 cm-1 are belonged to symmetric and asymmetric stretching s of C-H. Finally, the weak singlet band in 3336.14 cm-1 is related to secondary Amines that results in chlorine in silica chloro propyle is substituted by Amine group in 2-amino thio phenol . The standard stock solutions of Fe3+, Cd2+, K+ were prepared by dissolving appropriate amounts of corresponding nitrate salts in deionized water. The pH of metal solutions was about 6 & standard stock solutions of Co2+, Cu2+, Ni2+, Zn2+ was prepared by dissolving appropriate amounts of corresponding nitrate salts in tris buffer. The pH of metal solutions was adjusted to a desirable value of 7.4 by thisbuffer.