On-line solid phase selective separation and preconcentration of Cd(II) by solid-phase extraction using carbon active...

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Materials Science

Background:

• Accurate determination of trace cadmium (Cd) is crucial for environmental monitoring.
• Existing preconcentration methods may lack selectivity or efficiency.
• Development of rapid and sensitive analytical techniques for cadmium is needed.

Purpose of the Study:

• To develop a selective and efficient on-line sorbent extraction preconcentration system for cadmium.
• To utilize activated carbon modified with methyl thymol blue for cadmium adsorption.
• To determine trace cadmium in environmental samples using flame atomic absorption spectrometry.

Main Methods:

• An on-line flow system coupled with sorbent extraction was employed.
• Cadmium ions were adsorbed onto methyl thymol blue-modified activated carbon.
• Elution with 0.5M nitric acid followed by flame atomic absorption spectrometry (FAAS) determination.

Main Results:

• The modified activated carbon exhibited a high adsorption capacity (80 µg Cd(II)/g).
• Optimal preconcentration occurred at pH 9.0, with quantitative desorption by 0.5M HNO(3).
• A low detection limit (<1 ng/mL), high enrichment factor (1000), and linearity up to 2000 ng/mL were achieved.

Conclusions:

• The developed on-line method is selective, efficient, and repeatable for cadmium preconcentration.
• The method demonstrated satisfactory accuracy when applied to water, sewage sludge, and seawater samples.
• This technique provides a reliable approach for trace cadmium analysis in complex environmental matrices.