Synergistic DTPA-functionalized alginate/ZIF-90-derived oxide composite for ultraefficient removal of lead and methylene blue from aquaculture wastewater.

Industrial wastewater often contains various pollutants such as heavy metals and organic dyes, but most of the current adsorbents only show high performance under single-substance conditions and are still limited in adsorption capacity, kinetic rate, and reusability. To address this research gap, the work proposes a ZZO@ALG-DTPA composite material integrating ZIF-90/zeolite hybrid oxide (ZZO) and Diethylenetriaminepentaacetic acid-functionalized alginate (ALG-DTPA), creating a multifunctional adsorption platform for the separate treatment of Pb2+ and methylene blue (MB). The material shows outstanding adsorption efficiency and capacity, reaching a maximum q max = 1114.7 mg g-1 (Pb2+) and 787.41 mg g-1 (MB) followed by the Langmuir equation (R 2 = 0.988-0.975). The kinetics followed pseudo-second-order (R 2 = 0.999), confirming the chemical adsorption mechanism dominated by the coordination interaction -COO-/-NH2 with Pb2+ and charge interaction with MB. The optimum conditions were achieved at pH = 7, dosage 20 mg, equilibrium time 20 min, with the removal efficiencies of 96.98% (Pb2+) and 98.85% (MB), respectively. Ca2+ reduced Pb2+ removal by 50%, while monovalent ions had minimal impact, and the efficiency remained ≥85% in multi-ion systems. The material remained stable after 5 regeneration cycles, 85.43% efficiency for Pb2+ and 89.94% for MB, while demonstrating good ion resistance and high efficiency in complex real-water matrices (75.47-87.35% for Pb2+ and 80.55-88.96% for MB). These results prove that ZZO@ALG-DTPA is a promising, highly efficient, and renewable-based sorbent material for the treatment of multi-polluted wastewater.