The Jovanović adsorption isotherm in water contaminant research: Unmasking spurious versions and spotlighting the real thing

•Two versions of the Jovanović isotherm are defective because they yield nonsensical parameter estimates.•The genuine Jovanović isotherm differs from the Langmuir isotherm.•The Jovanović isotherm for multilayer adsorption has limited modeling power.•A new version outperforms the original formulation in correlating sigmoid data.•Assuming Jovanović local behavior, global isotherms are proposed.