Passive monitoring of trace metals in water by in situ sample preconcentration via chelation on a textile based solid sorbent

A simple, inexpensive, passive monitor, based on a textile-bound polyacryloamidoxime chelating agent (polyacryloami-doxime cloth), was evaluated for the analysis of selected trace heavy metals in water using both Energy Dispersive X-Ray Fluorescence (EDXRF) Spectroscopy and Wavelength Dispersive X-Ray Fluorescence (WDXRF) Spectroscopy as a means of analysis. Acid leaching of the sorbed metals followed by Graphite Furnace Atomic Absorption (GFAA) Spectroscopy was also carried out. It was shown that, in controlled in vitro experiments using a flow chamber, the sorption profiles of Pb and Cu by the cloth used were similar to those of chelating resins and fibres containing the amidoxime group. The rate of uptake of metals by the cloth was found to be dependent on the percent surface area converted to amidoxime groups, the concentration and type of metal being tested for, the time of exposure, the flow rate of solution and the temperature of solution. Distribution coefficients of 3.5 × 106 and 1.5 × 106 for Cu(II) and Pb(II) were observed and indicate a high degree of sample preconcentration. The average rates of uptake for Cu and Pb per gram of cloth were 600 and 200 mg per day respectively from dilute solution ([Cu] = 5.9 mg 1−1, [Pb] = 2.8 mg 1−1). From replicate samples, a relative error of < 10% was observed for the sorption of Cu and Pb. Experimental results of field tests involving the passive monitoring of river water and lake water under various conditions suggest that a number of ions can be identified and monitored simultaneously. The deployment of the monitors by the general public and the use of a mailing program was tested and shown to be practical. These results indicate the feasibility of using polyacryloamidoxime cloth as a passive monitor for trace metals in water.