Environmental Technology & Innovation 17 (2020) 100534 Contents lists available at ScienceDirect Environmental Technology & Innovation journal homepage: www.elsevier.com/locate/eti Application of the KIM Equation for direct analysis of Pb and Ni by EDXRF in lignocellulosic fibers used as adsorbents of metals Caroline S. Santana, Ohana N. de Almeida, Francisco H.M. Luzardo ∗ , Miriam S. Tokumoto, Fermin G. Velasco State University of Santa Cruz, Department of Exact and Technological Sciences, Jorge Amado Highway, Ilhéus, Bahia, Brazil article info Article history: Received 22 July 2019 Received in revised form 5 November 2019 Accepted 7 November 2019 Available online 11 November 2019 Keywords: Lignocellulosic adsorbents Correction for matrix effect KIM Equation EDXRF abstract The disposal of metals such as Ni and Pb resulting from anthropogenic activities is a matter of great concern due to the high solubility of these ions in water resources. Recent studies have used lignocellulosic adsorbents for the adsorption of these metals due to their high adsorption capacity. However, the methods developed for the quantification of these metals in lignocellulosic adsorbents have involved lengthy sample preparation processes and generated acid residues from their digestion. This work proposes a methodology for the quantification of Ni and Pb in lignocellulosic adsorbents using direct analysis by EDXRF associated with the simple application of the KIM Equation for matrix effect correction. For this, we used a standard with characteristics similar to the adsorbent matrix, the certified reference material Pine Needles. The adsorbents selected for this study were endemic species from the region, Eichhornia crassipes root, Attalea funifera fiber, Cocos nucifera bark and Eucalyptus globulus. FTIR and XRD analyzes confirmed the similarity between these matrices. According to the Kolmogorov–Smirnov test, matrix effect correction was efficient for the Eichhornia crassipes Pb curve, p = 0.999, Ni curve for Eucalyptus globulus, p = 0.963, and Pb and Ni curves for Cocos nucifera,p= 0.937 and p = 1.000, respectively. The statistical test showed marked proximity between the curve points of the standard and the adsorbents after the application of the KIM Equation. © 2019 Elsevier B.V. All rights reserved. 1. Introduction In recent years society has faced a severe period of environmental crisis, due to the contamination of water resources by toxic metals from the most diverse anthropogenic activities. The disposal of metals such as Ni and Pb from industrial activities, mining waste and sewage networks has become a major concern for environmental authorities, since they can enter the food chain and accumulate in living organisms. To reach even human beings, due to the high solubility of these ions in the bodies of water (Neris et al., 2018a). The presence of these ions in water bodies is a potential threat not only to human health but also to flora and fauna, since they are considered to be toxic and carcinogenic species. Ni and Pb, when found in nature at concentrations close to 0.20 mg L −1 and 0.006 mg L −1 , respectively, may promote damage to the fetal brain, diseases of the kidneys, circulatory ∗ Corresponding author. E-mail addresses: carolsantana.css@gmail.com (C.S. Santana), ohana_1992@hotmail.com (O.N. de Almeida), fmartinezluzardo@gmail.com (F.H.M. Luzardo), miriam.tokumoto@gmail.com (M.S. Tokumoto), fermingv@gmail.com (F.G. Velasco). https://doi.org/10.1016/j.eti.2019.100534 2352-1864/© 2019 Elsevier B.V. All rights reserved.