While　many　studies　have　successfully　used　plant　extracts　to　biosynthesize　iron　nanoparticles　as　low-cost,　sustainable　and　high-performance　materials　for　removing　Cr(VI)　from　aqueous　solution,　the　exact　removal　mechanism　involved　remains　poorly　understood.　In　this　research,　a　green　tea　extract　was　employed　both　as　a　reducing　and　coating　agent　to　prepare　iron　nanoparticles　(GT-nFe)　via　an　environmentally　friendly　green　synthesis　method,　where　the　material　so　produced　was　then　used　to　remove　Cr(VI)　from　aqueous　solution.　The　efficiency　in　removing　Cr(VI)　using　GT-nFe　reached　90.2　%　at　an　initial　Cr(VI)　concentration　of　60　mg　L-1　and　pH　of　5.0.　Kinetic　and　thermodynamic　analysis　indicated　that　Langmuir　isotherm　and　pseudo-second　order　models　best　described　the　adsorption　of　Cr(VI)　by　GT-nFe.　Thermodynamic　studies　revealed　that　adsorption　was　spontaneous　(Delta　G(0)＜0)　and　endothermic　(Delta　H-0＞0).　Application　of　advanced　characterization　techniques,　including　SEM-EDS,　TEM　and　XPS,　indicated　a　detailed　Cr(VI)　removal　mechanism　involving　both　adsorption　and　redox　reactions.　(C)　2021　Elsevier　B.V.　All　rights　reserved.