A　copolymer　flocculant　(CATCS)　derived　from　starch　and　chitosan　was　fabricated　and　used　as　eco-friendly　adsorbent　for　removal　of　Cr(VI)　from　aqueous　solution.　The　CATCS　flocculant　was　characterized　by　scanning　electron　microscope,　thermogravimetic　analysis,　and　Fourier　transform　infrared　spectroscopy.　The　effects　of　CATCS　dosage,　initial　Cr(VI)　concentration,　pH,　and　reaction　time　on　removal　of　Cr(VI)　were　discussed.　The　results　showed　CATCS　removed　Cr(VI)　effectively　and　the　adsorption　isotherm　agreed　well　with　the　Freundlich　isotherm　and　R–P　isotherm　models.　The　enthalpy　change　(ΔH)　of　the　process　was　16.75　kJ/mol　suggesting　the　existence　of　chemisorption　and　the　reaction　was　endothermic.　Moreover,　the　negative　free　energy　change　(ΔG)　indicated　the　adsorption　process　was　feasible　and　spontaneous.　The　positive　entropy　change　(ΔS)　showed　there　was　an　increase　of　disorder　in　the　system　during　the　adsorption　process.　The　adsorption　kinetics　results　showed　that　the　adsorption　could　be　described　by　the　pseudo-second-order　kinetics　mechanism.　The　activation　energy　(Ea)　of　the　adsorption　reaction　was　29.16　kJ/mol.　POLYM.　ENG.　SCI.,　56:1213–1220,　2016.　©　2016　Society　of　Plastics　Engineers.　©　2016　Society　of　Plastics　Engineers