Reply for the comment

In a recent publication by Liao et al., the section 1.3 Modeling of adsorption kinetics, authors mentioned a pseudosecond-order model from eq. (3) to eq. (5). In fact, the second order kinetic expression for the adsorption systems of divalent metal ions using sphagnum moss peat has been reported by Ho. In order to distinguish the kinetics equation based on adsorption capacity of solid from concentration of solution, Ho’s second order rate expression has been named pseudo-second order. The most frequently cited papers were published in Chemical Engineering Journal, Process Biochemistry and Water Research.