Trace metals and ions in particulates emitted by biodiesel fuelled engine

•Trace metals & inorganic ions in particulate from B20 & diesel exhaust.•Inorganic ions: nitrates, chlorides, fluorides & sulphates were measured.•Trace metals & Ions in particulate decreased with increasing load.•Biodiesel particulate had slightly lower trace metals & inorganic ions.•Morphological studies showed reduction in particulate with DOC. Particulates emitted by a transportation diesel engine fuelled with Karanja biodiesel blend (20% v/v biodiesel blended with 80% v/v mineral diesel) were tested for the trace metal content and inorganic ions. These particulate were analyzed and compared with baseline mineral diesel particulate for 9 commonly present trace metals namely Ca, Fe, Cr, Cu, Mn, Pb, Ni, Ba and Cd and inorganic anions such as nitrates, chlorides, fluorides and sulphates. Trace metals in particulate decreased with increasing engine load. Ions analyzed in particulate from diesel and biodiesel also showed decreasing trend with increasing engine load. Biodiesel origin particulate contained slightly lower amount of trace metals and inorganic ions compared to mineral diesel for similar operating conditions except nitrates. Particulate sampled on the quartz filter paper were also analyzed for their morphology and 1000× magnification images were captured using scanning electron microscopy (SEM) in order to visualize bulk particulate emission from Karanja biodiesel exhaust compared to baseline mineral diesel.