Biodiesel production from soybean oil deodorizer distillate usingcalcined duck eggshell as catalyst

•Calcined DES was used as catalyst for biodiesel production from SODD.•The obtained CaO was characterized by XRD, FT-IR, SEM and the optimal calcination temperature was 900°C.•The biodiesel yield was 94.6% at the optimal transesterification conditions.•The biodiesel yield was above 80% after five times usage.