Sawdust　was　expected　to　remove　impurities　in　waste　lubricant,　and　was　modified　with　sodium　hydroxide　and　triethanolamine,　which　can　ameliorate　its　surface　properties　and　improve　its　adsorption　capacity.　The　increase　of　hydroxyl　groups,　the　decrease　of　carbonyl　groups　and　grafting　new　azyl　after　modification　were　beneficial　for　the　adsorption　of　impurities.　The　surface　area　of　modified　sawdust　is　0.969　m2　g−1,　which　is　nearly　1.39　times　as　much　as　raw　sawdust.　The　point　of　zero　charge　for　modified　sawdust　decreased　from　6.75　to　5.68　while　the　crystallinity　of　modified　sawdust　increased　from　40.35　to　56.16.　This　research　discovered　that　compared　with　raw　sawdust　and　filter　paper,　modified　sawdust　possessed　superior　adsorption　performances.　The　removal　percentages　for　Si,　Al,　Fe,　Cu　was　enhanced　from　2.54%,　20.34%,　16.55%,　0.26%　to　15.37%,　21.99%,　45.37%,　4.88%,　respectively,　while　that　for　oxidation,　aromatics,　sulphation,　soot　and　water　was　improved　by　4.33,　4.69,　0.76,　1.20,　1.28　times　at　80　°C　with　1000　rpm　for　12　h.　The　research　has　also　explored　the　optimum　adsorption　conditions　(adsorption　temperature,　adsorption　time　and　rotation　rate).　The　modified　sawdust　showed　a　stable　adsorption　capacity　for　impurities　under　different　adsorption　conditions.　©　2018　Elsevier　B.V.