Artificial dyes are persistent and poisonous water pollution that require environment friendly removing applied sciences, and metallic–natural frameworks (MOFs) have emerged as promising adsorbents for this goal. On this work, a defect-engineered zirconium-based UiO-66 framework was synthesized by an HCl-modulated solvothermal route. UiO-66 was then functionalized with silver nanoparticles by way of a post-synthetic impregnation–discount technique to kind an Ag/UiO-66 composite for the removing of the cationic dyes methylene blue (MB) and crystal violet (CV). The silver was recovered from electrical contact waste, thereby including a resource-recovery dimension to the synthesis. Powder X-ray diffraction, XPS, FTIR, SEM, and TEM supported the incorporation of metallic Ag⁰ nanoparticles (about 3.3 nm; 3.11 wt%), uniformly dispersed on the crystals, with full preservation of the UiO-66 framework. Silver loading decreased the BET floor space from 870 to 642 m2 g−1, indicating partial pore occupation. However, Ag/UiO-66 exhibited greater Langmuir capacities than pristine UiO-66, reaching 113.49 and 46.72 mg g−1 for MB and CV, respectively, in contrast with 104.98 and 43.72 mg g−1 for the pristine framework. Elimination efficiencies above 98% had been achieved at impartial pH, with equilibrium attained inside 45 min. The adsorption was favored above the purpose of zero cost (pHpzc = 5.88) by way of electrostatic attraction, adopted the pseudo-second-order kinetic mannequin, and was greatest described by the Langmuir isotherm (R2 > 0.98), indicating monolayer adsorption. Thermodynamic evaluation indicated a spontaneous, exothermic course of, with ΔH° values starting from − 4.91 to − 9.31 kJ mol−1. The mixed isotherm, kinetic, and spectroscopic outcomes indicated that the uptake happens by way of each bodily and chemical interactions, together with electrostatic attraction, π–π stacking, hydrogen bonding, and binding on the silver and defect websites. The composite retained over 90% removing after 5 adsorption–desorption cycles and eliminated 95.3% of MB and 93.6% of CV from Nile River water. These outcomes exhibit that silver recovered from digital waste can be utilized to arrange efficient, reusable Ag/UiO-66 adsorbents for the removing of cationic dyes.
Sustainable synthesis of Ag/UiO-66 composites using recycled silver for efficient adsorption of methylene blue and crystal violet
