Synthesis, characterization, and catalytic application of metal-organic framework-based nanocomposites for photocatalytic degradation of pharmaceutical contaminants in wastewater

Project Abstract

This study reports the rational design, synthesis, and comprehensive characterization of metal-organic framework (MOF)-based nanocomposites integrated with noble metal, semiconductor, and carbonaceous materials to enhance photocatalytic degradation of pharmaceutical contaminants in wastewater under visible-light irradiation. The MOF component serves as a tunable, porous platform with high surface area, adjustable band structure, and robust chemical stability, enabling efficient adsorption of diverse drugs and persistent pharmaceutical pollutants (PPCPs). A facet-engineered Zr-based MOF (UiO-66) and a Ti-based MOF (MIL-125-NH2) were utilized as primary frameworks, functionalized with noble metal nanoparticles (Ag, Au) and coupled with graphitic carbon nitride (g-C3N4) or reduced graphene oxide (rGO) to construct type II heterojunctions and Z-scheme-like configurations. The synthesis employed solvothermal and hydrothermal routes with controlled pH, ligand-to-metal ratios, and post-synthetic modification to tailor pore accessibility, light-harvesting ability, and charge separation efficiency. Comprehensive physicochemical characterization included powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) surface area analysis, X-ray photoelectron spectroscopy (XPS), diffuse reflectance UV-Vis spectroscopy (DRS), photoluminescence (PL) spectroscopy, and electrochemical impedance spectroscopy (EIS) to elucidate structural, optical, and electronic properties and to quantify charge-transfer dynamics within the composites. Photocatalytic performance was evaluated against a suite of pharmaceutical contaminants, including diclofenac, ibuprofen, sulfamethoxazole, and carbamazepine, in simulated and real wastewater matrices under visible-light irradiation and at environmentally relevant concentrations. Reaction kinetics were monitored by high-performance liquid chromatography (HPLC) and liquid chromatography–mass spectrometry (LC-MS) to identify degradation intermediates and mineralization extent via total organic carbon (TOC) analysis. The synergistic effects of MOF pore confinement, semiconductor coupling, and noble metal plasmonic enhancement were investigated to unveil the driving forces behind improved adsorption, light absorption, and reactive oxygen species (ROS) generation—notably hydroxyl, superoxide, and singlet oxygen species. Radical scavenging experiments and electron spin resonance (ESR) spectroscopy were employed to delineate the dominant reactive species and to map the charge-transfer pathways. A comparative study across different composite formulations enabled optimization of loading ratios, interfacial contact, and crystallinity, achieving up to an order of magnitude enhancement in degradation rate constants relative to single-component controls. Stability and recyclability assessments demonstrated minimal loss of activity over multiple cycles, with post-reaction analyses confirming structural integrity and sustained porosity. Mechanistic insights suggest a dual-pathway operation (i) rapid interfacial electron transfer from excited MOF to coupled semiconductors and noble metal sites, and (ii) persistent ROS production facilitated by enhanced light harvesting and charge separation, enabling effective mineralization of recalcitrant PPCPs. The outcomes offer a scalable framework for designing MOF-based photocatalysts with tailored interfacial chemistry and robust performance in complex wastewater environments, contributing to environmentally sustainable strategies for mitigating pharmaceutical pollution.

Project Overview

What This Project Is About

---

This project explores how tiny, carefully designed materials called metal-organic frameworks (MOFs) can help break down pharmaceutical compounds found in wastewater. It focuses on making MOY-based nanocomposites, testing their ability to use light to trigger chemical reactions that dismantle pollutants, and understanding how well they work in real water-like conditions.

---

---

The Problem It Addresses

---

Pharmaceutical contaminants are hard to remove with ordinary water treatment and can harm ecosystems and human health. Current methods can be costly or generate secondary waste. The project seeks a more efficient, sustainable way to clean water using light-driven catalysts that target common drug residues.

---

---

Objectives of the Project

---

1. Design and synthesize MOF-based nanocomposites that respond to light.
2. Characterize structure, composition, and surface properties of the materials.
3. Evaluate photocatalytic performance against representative pharmaceutical pollutants.
4. Study how reaction conditions affect degradation efficiency (pH, light, contaminants).
5. Investigate reusability and stability of the catalysts over multiple cycles.

---

---

What You Will Do Step by Step

---

1. Literature review to identify target drugs and suitable MOFs. 2. Synthesize MOF nanocomposites in the lab. 3. Use instruments to characterize size, structure, and composition. 4. Test photocatalytic degradation under light exposure and measure pollutant levels. 5. Explore different water conditions and catalyst loadings. 6. Analyze data to find best-performing setups. 7. Assess catalyst reuse and durability. 8. Compile results into a report and prepare a presentation.

---

---

Expected Outcome

Anticipated results include a MOF-based catalyst that efficiently degrades pharmaceutical pollutants under light, a clear understanding of how material properties affect performance, and practical insights into catalyst longevity and potential scalability for wastewater treatment.