Preconcentration of Zn(II) in water samples using a new hybrid SBA-15-based material

A SBA-15 mesoporous silica has been chemically modified with 5-mercapto-1-methyltetrazole. The newly synthesized material (MTTZ-SBA-15) has been characterized, by powder X-ray diffraction, N2 adsorption, FT-IR, 13C NMR spectroscopy and elemental analysis, and used to preconcentrate Zn(II) in water samples. The effect of some variables on the adsorption capacity has been studied using the column techniques. The adsorption capacity of the prepared material followed the order: Zn >> Cu > Cd >> Mn, and under optimized conditions the maximum adsorption value for Zn(II) was 0.96 ± 0.01 mmol/g with the adsorption efficiency of 0.76. In column experiments, adsorption was quantitative for 1000 mL of 7.65 x 10-4 mM of Zn(II) solution and adsorbed ions were eluted out by 5 mL of 1 M HCl (preconcentration factor of 200). Spiked tap water and mineral water were used for the preconcentration and determination of Zn(II) by flame atomic absorption spectrometry (FAAS), and a 102 ± 2 and 98 ± 3% recoveries were obtained. The LOD and LOQ values of the proposed method were found to be 8.0 x 10-6 and 1.23 x 10-5 mM, respectively. The relative standard deviation for four preconcentration experiments was found to be ≤4% in all cases.