Photocatalytic Degradation of Diazinon with a 2D/3D Nanocomposite of Black Phosphorus/Metal Organic Framework

Abstract

Metal–organic frameworks (MOFs) are promising materials for the removal and photodegradation of pesticides in water. Characteristics such as large surface area, crystalline structure and catalytic properties give MOFs an advantage over other traditional adsorbents. The application of MOFs in environmental remediation is hindered by their ability to only absorb in the UV region. Therefore, combining them with an excellent charge carrier 2D material such as black phosphorus (BP) provides an attractive composite for visible-light-driven degradation of pesticides. In the study, a nanocomposite of black phosphorus and MIL-125(Ti), defined as BpMIL, was prepared using a two-stage hydrothermal and sonication route. The as-prepared composite was characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS) and photoluminescence (PL) spectroscopy. These techniques revealed that the circular and sheet-like morphology of the nanocomposites had minimum charge recombination, allowing them to be effective photocatalysts. Furthermore, the photocatalysts exhibited extended productive utilization of the solar spectrum with inhibited recombination rate and could be applied in visible-light-driven water treatment. The photodegradation of diazinon in water was studied using a series of BpMIL (4%, 6% and 12% by mass) nanocomposites as a photocatalyst. The optimal composite was determined to be 4%BpMIL. The degradation parameters were optimized and these included photocatalyst dosage, initial diazinon concentration and pH of the solution. The optimal conditions for the removal and degradation of diazinon were: neutral pH, [diazinon] = 20 mg/L, photocatalyst dosage = 0.5 g/L, achieving 96% removal of the pesticide after 30 min with 4%BpMIL, while MIL-125(Ti) showed 40% removal. The improved photodegradation efficiency of the 4%BpMIL composite was attributed to Ti3+-Ti4+ intervalence electron transfer and the synergistic effect between MIL-125(Ti) and BP. The photodegradation followed pseudo-first-order kinetics with a rate constant of 1.6 × 10−2 min−1.

Recent Progress on Synthesis and Properties of Black Phosphorus and Phosphorene As New-Age Nanomaterials for Water Decontamination

“…Overall, the physical and chemical characterization results proved that the MIL-125­(Ti)-FLBP catalyst could be used as a visible-light-responsive photocatalyst for contaminant treatment in water. The authors also synthesized and utilized a 2D/3D BP-MOF nanocomposite of BP-MOF for removal of diazinon from water via photocatalytic degradation . BP, MIL-125 (Ti), and BpMIL photocatalysts were synthesized using a two-step sonication and hydrothermal method.…”

“…The authors also synthesized and utilized a 2D/3D BP-MOF nanocomposite of BP-MOF for removal of diazinon from water via photocatalytic degradation. 105 BP, MIL-125 (Ti), and BpMIL photocatalysts were synthesized using a two-step sonication and hydrothermal method. The chemical and physical features of the photocatalysts were analyzed using SEM, TEM, XRD, electrochemical impedance spectroscopy (EIS), photoluminescence (PL), and XPS photoelectron spectroscopy.…”

Metal–Organic Frameworks as Potential Agents for Extraction and Delivery of Pesticides and Agrochemicals

“…Other studies on the adsorption of diazonin in aqueous media 106 have also determined neutral pH to be optimum for adsorption. In a study by Hlophe et al, MIL-125(Ti) was used as a composite of black phosphorus (BP) for the collection and photocatalysis of diazonin.…”

Synthesis of CoFe 2 O 4 @ZnMOF/Graphene nanoflake for photocatalytic degradation of diazinon under visible light irradiation: Optimization and modeling using a fractional factorial method

“…There are different mechanisms for removing pesticides from wastewaters, and while one method may be deemed appropriate for several pollutants but not appropriate for other pesticides. However, these procedures can still be classi ed as physical treatment like adsorption [8], chemical methods [9], biodegradation [9], coagulation and occulation [10], membrane separation [11], ozonation (oxidation) [12], and ultraviolet degradation process [13].…”