Treatment of microcystin-LR cyanotoxin contaminated water using Kentucky bluegrass-derived biochar

•Biochar was prepared from various waste biomass at different pyrolytic temperature.•Kentucky bluegrass-derived biochar was the best for microcystin-LR adsorption.•Selected biochar revealed maximum adsorption capacity of 2769 μg MC g−1 BC.•Adsorption of microcystin-LR followed Elovich, and Freundlich models.•Metal ions in real wastewater interfered the adsorption of microcystin-LR to biochar.