High efficient adsorption and colorimetric detection of trace copper ions with a functional filter paper.

A simple, cheap and effective functional paper has been fabricated to absorb and detect Cu 2+ with good sensitivity and selectivity. Using commercial cellulose filter papers as substrate, Magneli phase structure of Ti 6 O 11 was coated at the surface to serve as intermediate linker to modify N-[3-(Trimethoxysilyl) propyl] ethylenediamine for Cu 2+ binding. Under optimized conditions, i.e. at 50 °C with electromagnetic stirring, the functional paper can adsorb Cu 2+ with high performance and give clear color response using cupron as chromogenic agent. The concentration-dependent colorimetric response (Δ B value) matches well with the exponential linear curve under dynamic adsorption conditions, where the linear range was from 33.6 nM to 39.8 μM and the detection limit was measured to be about 33.6 nM. Measurement of a group of possible interfering ions and spiked real water samples demonstrated the good selectivity of the proposed paper. Furthermore, the performance can be further improved using microwave irradiation, where a lower detection limit of 16.8 nM was achieved within a wider linear range from 16.2 nM to 0.98 mM. The reaction time can be shortened to 20 min to reach final equilibrium and the saturated adsorption amount of Cu 2+ for a single piece of paper (diameter = 1.0 cm) was as high as 4.5169 μg/cm 2 . The proposed functional papers would offer an effective alternative for potential adsorption and determination of copper ions in real applications. [ABSTRACT FROM AUTHOR]