Pharmaceutical pollutants represent a growing environmental concern due to their persistence, toxicity, and potential for bioaccumulation. These contaminants enter water systems through human and animal excretion, improper disposal, and industrial effluents, leading to long-term ecological risks. Among the emerging technologies for water remediation, layered double hydroxides (LDHs) have emerged as highly effective materials for removing pharmaceuticals due to their tunable structure, high surface area, and multifunctional properties. This review focuses on the molecular engineering of LDHs and their applications in adsorption, photocatalysis, Fenton-like processes, and membrane technology for efficient removal of pharmaceutical pollutants.
The structural versatility of LDHs allows precise control over their composition and morphology. By adjusting the ratio of divalent and trivalent metal cations such as Mg²⁺, Al³⁺, Fe³⁺, or Zn²⁺, researchers can tailor the charge density and interlayer spacing, which enhances anion exchange capacity and facilitates the incorporation of various organic and inorganic species. The ability to intercalate anions like nitrate, carbonate, or even drug molecules makes LDHs ideal candidates for targeted pollutant capture. Furthermore, the synthesis method—whether direct precipitation, urea hydrolysis, or post-calcination reconstruction—plays a critical role in determining particle size, crystallinity, and surface characteristics.RAD23A Antibody Biological Activity For instance, hydrothermal treatment yields nanoscale particles with enhanced surface reactivity, while calcination produces mixed metal oxides (MMOs) that exhibit “memory effect,” enabling reconstruction into the original layered structure upon hydration.MAGEB4 Antibody custom synthesis
Adsorption remains one of the most widely used mechanisms for pharmaceutical removal. LDH-based composites show high capacities for drugs such as tetracycline, diclofenac, and ciprofloxacin, often exceeding 500 mg/g. Mechanisms include electrostatic attraction, hydrogen bonding, ion exchange, and π–π interactions, particularly when LDHs are combined with carbon-based materials like graphene oxide or activated carbon. These hybrid materials improve dispersion, reduce aggregation, and increase available active sites. Factors such as pH, temperature, ionic strength, and initial concentration significantly influence adsorption efficiency. Optimal performance is typically observed at near-neutral pH values where the LDH surface carries a positive charge, favoring the retention of anionic pharmaceuticals.
In addition to adsorption, advanced oxidation processes (AOPs) leveraging LDHs have demonstrated exceptional degradation capabilities. Heterogeneous photocatalysis using LDHs under UV-visible light generates reactive oxygen species such as hydroxyl radicals (·OH), which mineralize recalcitrant compounds. Doping with metals like Ce³⁺, Ag, or Cu enhances visible-light absorption and charge separation. Similarly, sulfate radical-based AOPs activate peroxymonosulfate (PMS) via redox-active metal ions (Fe²⁺, Co²⁺, Mn²⁺), producing ·SO₄⁻ radicals capable of degrading complex pharmaceuticals. The presence of rare earth elements like La³⁺ improves catalytic stability and promotes multiple radical pathways including singlet oxygen formation.PMID:35052807
Fenton-like and electro-Fenton processes further expand the utility of LDHs by enabling in-situ generation of oxidants without requiring external chemical additions. Iron- or copper-based LDHs serve as catalysts in these systems, facilitating electron transfer and generating ·OH radicals efficiently even at neutral pH. Electrochemical modification of LDHs on conductive supports like carbon felt enhances their durability and reusability, making them suitable for continuous treatment systems.
Membrane technologies incorporating LDH nanoparticles into polymer matrices create mixed matrix membranes (MMMs) with improved selectivity and permeability. These MMMs effectively remove pharmaceuticals through adsorption and size exclusion, especially when LDHs are exfoliated and uniformly dispersed within the matrix. The functionalization of LDHs with surfactants like SDS enhances hydrophilicity and compatibility with polymers such as cellulose acetate.
Despite their advantages, concerns regarding ecotoxicity persist. Leaching of metal ions, especially from modified LDHs containing silver or copper nanoparticles, may pose environmental risks. Therefore, future designs must prioritize complete mineralization of pollutants and ensure safe recovery and disposal of spent materials. Overall, the combination of structural flexibility, catalytic activity, and regenerative capacity positions LDHs as promising tools for sustainable water purification.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com