Amine functional group was grafted to obtain modified persimmon waste gel (NH2–CPT) with the focus of development of selective recovery of molybdenum from rhenium. The adsorption behavior of the NH2–CPT gel for various metal ions at varying hydrochloric acid concentrations was studied. It is found that the NH2–CPT exhibits high affinity for Mo(VI) and no affinity for Re(VII), Cu(II), Fe(III), Mn(VII), and Zn(II) under the operating conditions. The maximum adsorption capacity for Mo(VI) is 172 mg·g−1, and the adsorption behavior obeys the Langmuir model. Owing to Mo(VI) as poly-anions, the adsorption mechanism of molybdenum anions could be explained as the anion exchange reactions at weak acid concentration, while neutral molecules could be explained as the complexation reactions at strong acid concentration, respectively. In addition, its excellent adsorption characteristics for Mo(VI) are confirmed by separation of Mo(VI) from Mo to Re containing industrial effluent.