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Showing 3 results for Metal-Organic Framework
Experimental study of adsorption of amoxicillin residue from water samples using nanocomposite based on zirconium metal-organic frameworks and porous polymers
Yadollah Yousefzadeh, Vida Izadkhah, Soheil Sobhanardakani, Bahareh Lorestani, Sedigheh Alavinia,
Volume 16, Issue 4 (3-2024)
Abstract
Background and Objective: Antibiotics as emerging pollutants are harmful to environmental health. Therefore, this study was conducted to investigate the efficiency of Uio-66-NH2@CS-Iso-Gu nanohybrid for the removal of amoxicillin (AMX) from aqueous solutions.
Materials and Methods: In this study, for the first time, guanidine and isocyanate monomers are cross-linked with chitosan. The combination of this polymer with organometallic compounds contributes to its chemical/thermal stability and reusability. Uio-66-NH2@CS-Iso-Gu nanohybrid was characterized using X-ray diffraction (XRD), Scanning electronic microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), and BET methods. Also, the effects of pH, initial concentration of AMX, contact time, and temperature were evaluated. Moreover, isotherm, kinetic and thermodynamics studies were performed.
Results: The results of TGA analysis showed that Uio-66-NH2@CS-Iso-Gu nanohybrid was resistant to temperatures up to 400 °C. Also, optimal adsorption of AMX occurred in the first 25 min. The synthesized nanohybrid has a surface area of 101.2 m2/g and a type IV isotherm. Acidic groups were present on the synthesized nanohybrid surface based on the pHpzc = 4.7. Langmuir (for 25 °C and 45 °C) and Freundlich (for 65 °C) isotherm models and pseudo-second-order kinetic models are more appropriate to fit the adsorption data with the experimental data. The maximum adsorption capacity of the synthesized nanohybrid was equal to 56.49, 40.65, and 0.382 mg/g at temperatures of 25°C, 45°C, and 65°C, respectively. Based on the findings, Uio-66-NH2@CS-Iso-Gu nanohybrid could be used for up to five cycles without significantly reducing their performance.
Conclusion: The results showed that Uio-66-NH2@CS-Iso-Gu nanohybrid has a significant efficiency for removing AMX and could be used as an effective adsorbent for the treatment of wastewater containing pharmaceutical residues.
 

Synthesis of new photocatalyst based on modified organic-mineral polymers with mixed zinc and cobalt oxides and its application in sonophotocatalytic degradation of 2,4-dinitrophenol
Mojtaba Yeganeh, Sevda Fallah, Hanieh Fakhri, Mahdi Farzadkia,
Volume 17, Issue 1 (6-2024)
Abstract
Background and Objective: Phenol compounds are commonly applied as raw materials in the production of pesticides, herbicides, and dyes. These compounds are toxic to animals, plants, and microorganisms. In this study, the sonophotocatalytic degradation of 2,4-dinitrophenol in aqueous solutions was investigated using organic-mineral polymer catalysts containing Zink and Cobalt oxides under visible light and ultrasonic (US) irradiation.
Materials and Methods: The characteristics of the synthesized catalyst were determined using XRD, FTIR, and SEM techniques. The effect of several key parameters, including pH (3-9), catalyst dosage (0.3-1 g/L), time (0-90 min), US power (100-200 W/m2), and initial concentration of 2,4-dinitrophenol (20-100 mg/L), on the degradation efficiency was also investigated.
Results: After 75 minutes of sonophotocatalytic processing, complete degradation of 2,4-dinitrophenol (20mg/L) was achieved with catalyst dosage of 0.5 g/L, pH of 9.0, and US intensity of 200 W/m2. Kinetic studies indicated that the sonophotocatalytic degradation process followed a first-order kinetic model. The results of radical scavenging experiments confirmed that HO° and O2˚- radicals are the main oxidative species involved in the degradation of 2,4-dinitrophenol. Furthermore, the reuse of the catalyst for five consecutive tests showed a slight decrease in removal efficiency.
Conclusion: The results demonstrate that the sonophotocatalytic process, using the modified organic-mineral polymers with mixed Zink and Cobalt oxides catalyst, can be an effective method for removing 2,4-dinitrophenol from aqueous media.
 

Design and application of structured fluorometric sensor for melamine detection in milk powder
Mahmood Alizadeh Sani, Arezou Khezerlou, Mohammad Rezvani-Ghalhari, Gholamreza Jahed-Khaniki,
Volume 18, Issue 3 (12-2025)
Abstract
Background and Objective: Melamine is a chemical compound commonly used as an adulterant in food products. In this study, a fluorescence-based sensor utilizing an aluminum metal-organic framework (Al−MOF) was developed for the detection of melamine in milk powder.
Materials and Methods: In this study, Al-MOF was employed as a sensing material due to its high fluorescence properties and strong ability to adsorb melamine. Using fluorescence techniques, the sensitivity and selectivity of the sensor towards melamine were evaluated over a concentration range of 0 to 400 nanomolar (nM).
Results: The melamine concentration was determined based on the reduction in the fluorescence intensity of the Al-MOF. The effects of different parameters such as pH, reaction time, and concentration, on the performance of the designed sensor were evaluated. Under optimized conditions (pH = 9, reaction time < 1 min, and Al–MOF concentration of 30 mg/L), a good linear relationship (R2 = 0.99) was observed between fluorescence intensity and melamine concentration in the range of 0–400 nM, with a detection limit of 38.5 ppb. However, the limit of detection (LOD) for HPLC method was approximately 90 ppb, indicating that the designed sensor has higher sensitivity (about 2.3 times). The sensor also exhibited good selectivity for melamine. The recovery percentage and relative standard deviation (RSD) were found to be 97-103% and 1.2-2.8%, respectively.
Conclusion: This sensor can serve as an effective tool for quality control in dairy products due to its simplicity and rapid detection capabilities.
 

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