In　this　study,　the　torrefaction　biochar　from　bamboo　(Acidosasa　longiligula)　shoot　shell　under　different　torrefaction　intensities　(TI)　were　prepared　and　characterized.　Nonradioactive　Cr(VI),　a　chemical　surrogate　for　radioactive　Tc(VII),　was　used　to　evaluate　Tc(VII)　reductive　immobilization　of　torrefaction　biochar.　Batch　adsorption　experiments　indicated　that　torrefaction　biochar　had　strong　adsorption　ability　to　Cr(VI)　with　the　best　uptake　capacity　of　63.11　mg/g.　The　adsorption　kinetic　was　well　fitted　by　pseudo-second-order　model　and　Park　model.　The　adsorption　equilibrium　was　considerably　fitted　by　Freundlich　and　Temkin　isotherm　The　adsorption-reduction　mechanism　during　the　whole　Cr(VI)　immobilization　process　was　confirmed　by　the　Raman　spectrum　analysis　and　the　nice　fitting　of　Park　model.　This　study　demonstrates　that　torrefaction　bio　char　deserves　to　be　a　low-cost　and　effective　immobilization　material　for　Tc(VII).　(c)　2020　Taiwan　Institute　of　Chemical　Engineers.　Published　by　Elsevier　B.V.　All　rights　reserved.