Preparation and properties of a biomass cellulose-based colorimetric sensor for Ag+ and Cu2+

Abstract

A biomass cellulose-based colorimetric sensor for Ag+ and Cu2+ was prepared by grafting 2,5-dithiourea (DTu) onto biomass-pulp cellulose. The as-prepared sensor (cellulose-DTu) showed excellent selectivity and sensitivity towards Cu2+ over other common metal ions (Pb2+, Mn2+, Mg2+, Zn2+, Hg2+, K+, Al3+, Ca2+, Na+, Cd2+, Ni2+, Ba2+, and Li+), exhibiting a color change from white to light grey. However, the sensor exhibited a remarkable color change from white to yellow-red upon the addition of Ag+. The naked-eye-detection concentration limits for Ag+ and Cu2+ were 10−3 and 10-4 mol/L, respectively. Furthermore, cellulose-DTu responded to both Ag+ and Cu2+ within 5 s. A mechanism for the selective identification of Ag+ and Cu2+ by cellulose-DTu was proposed based on 13C solid NMR, XPS, and TEM analyses. In addition, the application of cellulose-DTu in real water confirmed that it exhibits the advantages of simplicity, rapidity, and high selectivity for in-situ identification of Ag+ and Cu2+.