A novel material, PyrC(350)(R), has been developed from pyrolytic-tire char (PyrC), as an efficient low-cost Arsenite [As(III)] adsorbent from water. PyrC(350)(R) achieves 31 mg g(-1) As(III) uptake, that remains unaltered at pH = 4-8.5. A theoretical Surface Complexation Model has been developed that explains the adsorption mechanism, showing that in situ formed Fe3C, ZnS particles act cooperatively with the carbon matrix for As(III) adsorption. Addressing the key-issue of cost-effectiveness, we provide a comparison of As(III)-uptake effectiveness in conjunction with a cost analysis, showing that PyrC(350)(R) stands in the top of [effectiveness/cost] vs. existing carbon-based, low-cost materials. (C) 2016 Elsevier B.V. All rights reserved.