Recent developments in metal-organic frameworks (MOFs) have gained great interest in the potentiometric sensing and adsorption removal of heavy metals. However, poor hydrochemical stability is the major challenge limiting MOFs (e.g., MOF-5) applicability in the real environmental field. Accordingly, the impregnation of MOF-5 with Zn0.05TiOxNy nanoparticles was proposed in this work to design a hydrochemical stable Zn0.05TiOxNy@MOF-5 nanocomposite for selective/sensitive adsorption and potentiometric sensing of Zn2+ ions in saline wastewater containing 10–140 g L-1 total dissolved solids (TDS). The results indicate that Zn0.05TiOxNy@MOF-5 outperformed MOF-5 for Zn2+ adsorption over five reuse cycles, with an initial uptake rate (ho) of 11.724 g mg-1 min-1 at 50 g L-1 TDS. Based on the kinetic, isotherm, and thermodynamic data, the adsorption of Zn2+ onto Zn0.05TiOxNy@MOF-5 is an endothermic and physisorption in nature (ΔHº = −12.02 kJ/mol), including electrostatic interaction and diffusion mechanisms as the main rate-limiting step. The modified screen-printed sensor (SPS) with Zn0.05TiOxNy@MOF-5 ionophore also exhibits good selectivity for Zn2+ sensing (detection limit (DL) of 2.1 × 10-8 mol L-1 = 0.0014mg L-1) over a wide working range of 10-1 to 10-8 mol L-1 (Nernstian slope = 29.7 ± 0.3 mV decade-1) and pH 3–9. At optimum pH 5, the practical usability of SPS-based Zn0.05TiOxNy@MOF-5 for Zn2+ detection was also recognized in real petroleum and sewage wastewaters with stable potentiometric response over six successive days. These findings concluded that Zn0.05TiOxNy@MOF-5 could be used as a promising adsorbent and ionophore for selective adsorption and potentiometric detection of Zn2+ ions at a real environmental scale.