Schiff Base Functionalized ZIF‐8‐GO Hybrid as an Efficient Adsorbent for Methylene Blue: A Comparative UV–Vis and DPV Study

Designing efficient adsorbent materials with high affinity toward synthetic dyes is essential for sustainable wastewater treatment. In this study, a Schiff base‐functionalized zeolitic imidazolate framework‐8/graphene oxide hybrid (En‐Sal‐ZIF‐8@GO) was developed and evaluated for methylene blue (MB) adsorption. The composite was synthesized via sequential Schiff base grafting and graphene oxide (GO) incorporation, yielding a microporous framework with a Brunauer–Emmett–Teller (BET) surface area of 950 m 2 g −1 and pore volume of 0.38 cm 3 g −1 , while retaining the structural integrity of ZIF‐8, as confirmed by powder x‐ray diffraction (PXRD) and Fourier‐transform infrared (FT‐IR) analyses. Scanning electron microscopy (SEM) images revealed polyhedral ZIF‐8 crystallites uniformly anchored on GO sheets, enhancing surface accessibility. Ultraviolet‐visible (UV–vis) analysis showed extended visible absorption due to π–π* interactions. The composite achieved 89% MB removal within 60 min compared to 47% for ZIF‐8, while differential pulse voltammetry (DPV) confirmed 86% removal at 90 min versus 52% for ZIF‐8. Enhanced adsorption is attributed to electrostatic interactions, π–π stacking, coordination via imine groups, and hydrogen bonding. The close agreement between UV–vis and DPV validates DPV as a reliable complementary technique for wastewater treatment applications.