Adsorption of Methylene Blue and Crystal Violet on Babaçu (Obignya phalerata) Coconut Epicarp and the Development of a New Hg(II) Electrochemical Sensor

In this work, babacu coconut epicarp (BCE), an abundant vegetal product of low cost from Maranhao State, Brazil, is studied as adsorptive agent toward dyes: methylene blue (MB) and crystal violet (CV). The physico-chemical analyses gave the following results for the vegetal matrix: 1.3; 8.0; and 0.44% for ashes, humidity, and lipids, respectively. It is verified that BCE can be successfully employed for the adsorption of MB and CV. The obtained results strongly suggest that similar results could be obtained for other dyes. Furthermore, the MB-modified BCE can be successfully employed as active species in the preparation of a carbon past electrode sensitive to Hg(II) cations.