Pertechnetate　(TcO4-)　is　a　component　of　low-activity　waste　(LAW)　fractions　of　legacy　nuclear　waste,　and　the　adsorption　removal　of　TcO4-　from　LAW　effluents　would　greatly　benefit　the　site　remediation　process.　However,　available　adsorbent　materials　lack　the　desired　combination　of　low　cost,　radiolytic　stability,　and　high　selectivity.　In　this　study,　a　ZnO　nanoparticle-anchored　biochar　composite　(ZBC)　was　fabricated　and　applied　to　potentially　separate　TcO4-　from　radioactive　effluents.　The　as-synthesized　material　exhibited　γ　radiation　resistance　and　superhydrophobicity,　with　a　strong　sorption　capacity　of　25,916　mg/kg　for　perrhenate　(ReO4-),　which　was　used　in　this　study　as　a　surrogate　for　radioactive　pertechnetate　(TcO4-).　Additionally,　the　selectivity　for　ReO4-　exceeded　that　for　the　competing　ions　I-,　NO2-,　NO3-,　SO42-,　PO43-,　Cu2+,　Fe3+,　Al3+,　and　UO22+.　These　unique　features　show　that　ZBC　is　capable　of　selectively　removing　ReO4-　from　Hanford　LAW　melter　off-gas　scrubber　simulant　effluent.　This　selectivity　stems　from　the　synergistic　effects　of　both　the　superhydrophobic　surface　of　the　sorbent　and　the　inherent　nature　of　sorbates.　Furthermore,　density　functional　theory　(DFT)　calculations　indicated　that　ReO4-　can　form　stable　complexes　on　both　the　(100)　and　(002)　planes　of　ZnO,　of　which,　the　(002)　complexes　have　greater　stability.　Electron　transfer　from　ReO4-　on　(002)　was　greater　than　that　on　(100).　These　phenomena　may　be　because　(002)　has　a　lower　surface　energy　than　(100).　Partial　density　of　state　(PDOS)　analysis　further　confirms　that　ReO4-　is　chemisorbed　on　ZBC,　which　agrees　with　the　findings　of　the　Elovich　kinetic　model.　This　work　provides　a　feasible　pathway　for　scale-up　to　produce　high-efficiency　and　cost-effective　biosorbents　for　the　removal　of　radionuclides.　©　2019　Elsevier　B.V.