Microwave-assisted synthesis of MCM-41 composite with rice husk and its functionalization by dithizone for preconcentration of some metal ions from water and food samples

A composite of MCM-41 silica with rice husk was modified with dithizone with the aid of microwave radiation. The modified composite was characterized by different techniques and utilized for preconcentration of Cu2+, Zn(2+ )and Pb2+ prior to determination by flame atomic absorption spectrometry (FAAS). The adsorption process is optimized to attain the maximum efficiency. The procedure presented satisfying uptake characteristics with maximum adsorption capacity of 142.7, 102.9 and 228.8 mg g(-1) towards Cu2+, Zn2+ and Pb2+, respectively. The calibration graphs were linear up to 400 mu g L-1 for Cu2+ and Zn2+ and up to 800 mu g L-1 for Pb2+ with pre concentration factor of 240. The limits of detection were 0.28, 0.21 and 0.48 mu g L(-1 )for Cu2+, Zn2+ and Pb2+, respectively. The optimized procedure was utilized for the preconcentration of Cu2+, Zn2+ and Pb2+ in water and food samples prior to determination by FAAS with accepted precision and accuracy.

Automated summary

A composite material of MCM-41 silica modified with dithizone was synthesized using microwave radiation. This modified composite showed high adsorption capacity for Cu2+, Zn2+ and Pb2+ and was used for preconcentration prior to determination by FAAS. The optimized procedure exhibited satisfactory uptake characteristics with linear calibration graphs and low detection limits for the three metals. It was successfully applied for preconcentration of Cu2+, Zn2+ and Pb2+ in water and food samples.