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 Cu2+ with good sensitivity and selectivity. Using commercial cellulose filter papers as substrate, Magneli phase structure of Ti6O11 was coated at the surface to serve as intermediate linker to modify N-[3-(Trimethoxysilyl) propyl] ethylenediamine for Cu2+ binding. Under optimized conditions, i.e. at 50 degrees C with electromagnetic stirring, the functional paper can adsorb Cu2+ with high performance and give clear color response using cupron as chromogenic agent. The concentration-dependent colorimetric response ( AB value) matches well with the exponential linear curve under dynamic adsorption conditions, where the linear range was from 33.6 nM to 39.8 mu M 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 Cu2+ for a single piece of paper (diameter= 1.0 cm) was as high as 4.5169 mu g/cm(2). The proposed functional papers would offer an effective alternative for potential adsorption and determination of copper ions in real applications. (C) 2015 Elsevier B.V. All rights reserved.