A　complex　of　water-hyacinth　derived　pellets　immobilized　with　Chlorella　sp.　was　applied,　for　the　first　time,　in　the　bioremediation　of　Cadmium　(Cd).　The　Cd(II)　removal　efficiency　of　the　complex　was　optimized　by　investigating　several　parameters,　including　the　pellet　materials,　algal　culture　age,　and　light　intensity.　Results　showed　that　the　Cd(II)　removal　efficiency　was　positively　related　to　the　algal　immobilization　efficiency　and　the　algal　bioaccumulation　capacity.　Since　higher　surface　hydrophilicity　leads　to　higher　immobilization　efficiency,　the　water-hyacinth　leaf　biochar　pellet　(WLBp)　was　selected　as　the　optimal　carrier.　A　maximum　Cd(II)　removal　efficiency　of　92.45%　was　obtained　by　the　complex　of　WLBp　immobilized　with　algal　cells　in　stationary　growth　phase　and　illuminated　with　a　light　intensity　of　119　μmol　m−2　s−1.　Recovery　tests　on　both　microalgal　cells　and　the　WLBp　demonstrated　that　the　algal　cells　and　the　biochar　pellet　can　be　economically　recycled　and　reused.　©　2018　Elsevier　Ltd