Application　of　biochar　as　an　adsorbent　for　wastewater　treatment　has　obtained　a　tremendous　research　interest　owning　to　their　low　cost　and　surface　functionality.　In　this　research,　an　iron　loaded　sludge　biochar　was　successfully　prepared　through　a　simple　and　economical　one-step　modification　hydrothermal　method.　The　iron　loaded　sludge　biochar　possesses　large　amounts　of　surface　organic　functional　groups　(such　as　hydroxy,　carboxyl　and　aromatic　ring,　etc.),　smaller　particle　size　(about　10　nm)　as　well　as　relative　higher　surface　area　(82.780　m(2)　g(-1))　than　of　the　pristine　one.　The　selective　removal　of　two　kinds　of　antibiotics　by　the　prepared　products　was　demonstrated.　Experimental　data　was　fitted　to　isotherm　and　kinetic　models,　and　thermodynamic　parameters　were　also　calculated.　In　the　single　antibiotic　system,　the　maximum　adsorption　amount　of　tetracycline　(TC)　and　doxycycline　(DOX)　could　reach　104.86　and　128.98　mg　g(-1)　at　293.15　K,　respectively.　In　the　binary　antibiotics　system,　there　was　an　antagonistic　effect　between　TC　and　DOX.　Furthermore,　the　adsorption　of　TC　was　much　more　inhibited　than　that　of　DOX　owning　to　its　deferent　steric　hindrance　of　molecular　structure.　(C)　2019　Elsevier　Ltd.　All　rights　reserved.