Optimization of preparation conditions for activated carbon from waste materials of agricultural origin for the removal of basic red 46

► The activated carbon by orthophosphoric acid adsorbs 94.8% of basic red 46. ► The adsorption of basic red 46 is performed in a batch system. ► The optimization is achieved by the complete factorial plan 24. ► The Spendley simplex permits to localize the zone of the best efficiency.