Colorimetric detection of copper and efficient removal of heavy metal ions from water by diamine-functionalized SBA-15

SBA-15 functionalized with N-[3-(trimethoxysilyl)propyl]ethylene-diamine (TPED) was synthesized and used for the colorimetric detection of Cu2+ and removal of heavy metal ions in aqueous solutions. Compared to free SBA-15, the adsorption ability of diamine-functionalized SBA-15 (depicted as SBA-TPED) increased remarkably, the maximum adsorption capacity of SBA-TPED for Cu2+, Pb2+ and Zn2+ was 27.22, 96.43 and 12.16 mg g(-1), respectively. Furthermore, SBA-TPED exhibits high selectivity for Cu2+ with the relative selectivity coefficient of SBA-TPED for Cu2+/Pb2+ being over 10 and for Cu2+/Zn2+ being over 60. The naked-eye detection limit of SBA-TPED for Cu2+ is 0.95 ppm, and the determination of Cu2+ in real water samples also displays satisfactory results. Moreover, SBA-TPED possesses fast kinetics for removing Cu2+ with a saturation time of less than 30 min, and can be regenerated by simple acid treatment.