Novel 2-acetylbenzothiazole modified mesoporous silicas for enriching trace heavy metal ions

Abstract

A novel 2-acetylbenzothiazole functionilised mesoporous silica based on SBA-15 was prepared, and then applied in fabricating a minicolumn to preconcentrate trace amount of heavy metal ions [e.g. Cd(II), Cu(II), Hg(II), Pb(II), etc.] in this study. Inductively coupled plasma atomic emission spectrometry was used to determine the concentration of metal ions in water samples. The precontration conditions including pH value, adsorption time, eluent solution and its volume and recoveries were examined. The obtained results are as follows. When 500 mL water samples went through this column with the pH of 2·2–6·5, the maximum adsorption capacity could reach 0·45±0·01 mmol g−1 for Pb(II), 0·56±0·02 mmol g−1 for Cd(II), 0·37±0·01 mmol g−1 for Cu(II) and 0·48±0·03 mmol g−1 for Hg(II) respectively. The saturated columns could be eluted by 2·5 mL ethanol (95%) and thiourea (0·5 mol L−1) (v/v, 1∶1) with preconcentration factor of 250. The detection limits (n = 11) were determined to be 0·02, 0·10, 0·13 and 0·04 μg L−1 for Cd(II), Cu(II), Hg(II) and Pb(II) respectively. The relative standard deviation for six replicate runs was better than 2·4%. This study provided a promising way to detect the trace amount of heavy metal ions in the water samples, which might be used in environmental protection and water quality monitoring.