In this study, chitosan and bio-based substances (BBS) obtained from composted biowaste were used as stabilizers for the synthesis of magnet-sensitive nanoparticles (NPs) via coprecipitation method. A pyrolysis treatment was carried out on both biopolymers at 550 degrees C, and their consequent conversion into a carbon matrix was followed by means of different physicochemical characterization techniques (mainly FTIR spectroscopy and XRD), whereas magnetic properties were evaluated by magnetization curves. The prepared materials were tested in water remediation processes from arsenic (As) species (both inorganic CON and organic forms). These tests, explained, by means of the Most common adsorption models, evidenced that the best performances were reached by both materials obtained after pyrolysis treatments, pointing out the promising application of such magnet-sensitive materials as easy-recoverable tools for water purification treatments. (C) 2017 Elsevier B.V. All rights reserved.