Cellulose acetate-polyurethane film adsorbent with analyte enrichment for in-situ detection and analysis of aqueous Pb using Laser-Induced Breakdown Spectroscopy (LIBS)

Abstract

In this work, we have investigated the potential application of cellulose acetate-polyurethane (CA-PU) film, as an adsorbent material as well as an enrichment medium for aqueous Pb quantification using Laser-Induced Breakdown Spectroscopy (LIBS). CA-PU was reported to be a good adsorbent for Pb removal from water medium due to its possession of O- and N-containing functional groups. The adsorption was first qualitatively investigated by observing Pb I (405.7 nm) emission line, before and after the adsorption. The study was further carried out using varied laser energies in order to optimize the produced spectra. The optimum laser energy was 54 mJ (gain = 1,500; width = 30 µs). The other aspects this work considered were contact time and pH, where the stable analysis was obtained after 12 h enrichment process and at pH 7. Normalization using C I (247.8 nm) internal standard line could compensate for the errors generated during the analysis. The non-linear regression of the calibration curve achieved correlation as high as R2 = 0.99997 and LOD = 1.02 mg/L. Based on the obtained LOD, this analytical method is suitable for the wastewater control in chemical industries in Indonesia. As an addition, LIBS is a potential technique to measure the binding energy of the adsorbent surface which requires further studies.