Optimization of Visible-Light-Driven Ciprofloxacin Degradation Using a Z-Scheme Semiconductor MgFe₂O₄/UiO-67

Abstract

A heterogeneous photocatalyst, MgFe 2 O 4 /UiO-67 (MU-x), was successfully synthesized by doping magnetic magnesium ferrite nanoparticles (MgFe 2 O 4 ) with the UiO-67 metal−organic framework at various weight ratios (MgFe 2 O 4 : UiO-67 at 30, 50, 70, and 90 wt %). Various techniques, including Xray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR) , Brunauer−Emmett−Teller (BET), photoluminescence (PL), vibrating sample magnetometry (VSM), electrochemical impedance spectroscopy (EIS), and ultraviolet−visible diffuse reflectance spectroscopy (UV−vis DRS), were used to characterize the prepared photocatalysts. The photocatalytic performance of MU-x in the degradation of ciprofloxacin (CIP) under visible light was assessed. The CIP degradation efficiency was found to increase as the amount of MgFe 2 O 4 in the composite was increased up to 70 wt %. Experimental conditions were optimized using response surface methodology (RSM) based on central composite design (CCD) with three factors: initial pH, catalyst loading, and CIP concentration. Using the obtained model, the optimal conditions were determined as follows: initial pH of 8.025, catalyst loading of 33.8 wt %, and CIP concentration of 10.8 mg/L. Under these optimal conditions, a notable improvement was achieved, with 99.62% of CIP removal achieved within 90 min, surpassing the performance of previously reported photocatalysts. Total organic carbon (TOC) analysis revealed a high degree of mineralization, at 81.25%. The degradation pathway of CIP was investigated based on liquid chromatography−mass spectrometry (LC-MS) analysis. Finally, the values of E CB and E VB of the photocatalyst were determined and the possible degradation mechanism of CIP was investigated based on Mott−Schottky and the applied scavengers. The hydroxyl radical ( • OH) was identified as the dominant species in the removal of CIP through a trapping experiment. The photocatalyst with 70 wt % of MgFe 2 O 4 (MU-70) exhibited excellent stability and recoverability with an external magnet, demonstrating 86.33% CIP removal after four cycles. According to the obtained results, MU-70 is a promising visible-light-active photocatalyst with great potential for water treatment applications and convenient recovery.

Porous Fe-Porphyrin as an Efficient Adsorbent for the Removal of Ciprofloxacin from Water

“…Fe-POP was synthesized by reacting pyrrole and terephthalaldehyde in the presence of FeCl 3 to form polymers of porphyrin blocks according to the reported procedure. 42 The Fe-POP solid-state 13 C NMR spectrum exhibited three resonance signals at δ: 129.3, 131.5, and 191.3, which could be assigned to the phenyl carbons, porphyrin macrocycles, and the terminal aldehyde groups, respectively (Figure S1). Figure 1a−c presents the morphology of Fe-POP as observed by scanning electron microscopy (SEM).…”

“…The porphyrin-based porous polymer Fe-POP adsorbent was successfully prepared through a one-pot Friedel−Crafts reaction involving pyrrole groups and terephthalaldehyde in the presence of FeCl 3 . The morphology, structure, and stability of as-prepared Fe-POP were studied by different characterization techniques, including SEM, EDX, FT-IR, BET, and solid-state 13 C NMR. Fe-POP exhibited a large specific surface area of 597 m 2 g −1 .…”

“…The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acsomega.3c09200. Scheme and solid-state 13…”

“…Ciprofloxacin (CIP), the most commonly prescribed fluoroquinolone antibiotic, has been observed in the wastewater of hospitals, pharmaceutical industries, and groundwater . There have been numerous treatment methods for the elimination of CIP from wastewater, such as membrane technology, ozonation, photocatalytic degradation, electrochemical degradation, and adsorption . Adsorption, which has suitable features for antibiotic removal from water like low cost, high performance, and flexibility, is known as a promising and popular method for removing CIP from wastewater. , Materials like activated carbon, semiconductor materials, and porous materials, including zeolites, silicates, metal–organic frameworks (MOFs), and porous organic polymers (POPs), have been used for removing CIP from water via the adsorption method.…”