Layered double hydroxides (LDHs) have gained increasing attention as versatile materials in environmental remediation, particularly for wastewater treatment. Their unique structural properties, such as tunable metal cation composition, interlayer anion exchange, and structural memory effects, make them suitable materials for a broad range of applications. In addition to these intrinsic properties, thermally treated LDH-derived mixed metal oxides have emerged as a key focus, exhibiting enhanced activity through tailored structural, electronic, and textural properties. This review presents an up-to-date and systematic overview of recent advancements in the design and application of LDH-based materials, with a focus on photocatalytic degradation of organic dyes, adsorption of contaminants, and light-activated antimicrobial activity. The review also explores emerging photocatalytic applications in correlation with surface engineering, heterojunction formation, and thermal activation to enhance the overall efficiency. In addition, the synergy between antimicrobial activity and photocatalysis is discussed in the context of achieving multifunctional microbial control in water treatment. Finally, current challenges and future perspectives are addressed, including recyclability, scale-up potential, and the development of LDH composites as sustainable alternatives to conventional photocatalysts. This review aims to support researchers in advancing LDH-based technologies toward more efficient and versatile environmental remediation solutions.

Photodegradation of azo dyes from industrial wastewater is challenging due to their high stability and resistance to removal. In this study, a generalized predictive model for photodegradation behavior of TiO2 containing ZnAl layered double hydroxide (LDH) based materials in the removal process of cationic azo dyes (Rhodamine B and Methylene Blue) was proposed. The performed kinetic investigation suggested good correlation of the experimental results with theoretical settings and revealed that all photocatalysts in both photocatalytic removal reactions followed the pseudo-first order Langmuir-Hinshelwood reaction model. The inputs for artificial neural network (ANN) included four experimental variables: TiO2 loading onto LDHs, organic dye type used for the removal process, temperature of thermal treatment of photocatalysts and reaction time, whereas for the two ANN prediction outputs removal efficiency and photo-degradation rate constants were used. The optimal topology was determined to be a three-layer feed-forward ANN with 3 input neurons and 10 hidden neurons, 3-10-1.

Due to favourable properties layered double hydroxides (LDHs) have been widely investigated for organic dye removal processes. In order to study the adsorption of methyl orange, bimetal (ZnAl and MgAl) and trimetal (ZnCuAl and MgCuAl) adsorbents were synthesized and thermally treated. The influence of adsorbent metal nature and content on structural (X-ray diffraction, Raman analysis), textural (low temperature nitrogen adsorption) and adsorption properties was investigated. Adsorption behaviour, mechanisms, and stability of synthesized LDHs and their calcined mixed oxides were studied with the aim to elucidate the adsorbent-dye interactions, enabling optimization of experimental design. All LDH adsorbents and LDH derived mixed oxide adsorbents had high removal efficiency rate, especially Zn-containing mixed oxides where complete decolourization (100 % of dye removal) was achieved almost instantly due to super-fast adsorbent-adsorbate interaction. Two possible adsorption mechanisms initiated by interfacial phenomena were in correlation with the structural and textural properties, as well as with the ?memory effect? reconstruction phenomenon. These results present a solid base for further investigation and design of LDH-based adsorbents for the Methyl orange removal, considering their favourable structural and textural properties and excellent adsorption capacities.

Organic dye pollutants that are progressively used in modern chemical industries, emerged as a major source of water contamination. A promising eco-friendly and simple approach to water purification is the heterogeneous photocatalytic process that uses various metal oxide semiconductors in the presence of light, initiating the oxidation-reduction reactions resulting in dye degradation. The aim of this study was to investigate the influence of coprecipitation synthesis methods on photodegradation efficiency. The ZnFe based photocatalysts were synthesized using two different methods: low (LS) supersaturation and high (HS) supersaturation coprecipitation and thermally activated at 100, 300, 500 and 700?C. Structural and textural characterisation were carried out and their efficiency in methylene blue photodegradation test reaction was studied. LS samples treated at 100 and 300?C exhibited very low photodegradation efficiency (less than 10 %) when compared to HS samples treated at the same temperatures (75 and 85 %). The efficiency of LS 500 and LS 700 samples improved (67 and 75 %) with the increase in thermal treatment temperature and the photodegradation efficiency difference between LS and HS samples decreased. Such behaviour of LS and HS samples could be explained by structural and textural properties that originated from different synthesis methods.

Layered double hydroxides (LDHs) and their derived mixed oxides are emerging as a promising class of biocompatible inorganic lamellar nanomaterials. The detailed structure and textural characteristics of the synthesized LDH-based materials were examined using X-ray diffraction, Fourier transform infrared spectroscopy, and N₂ adsorption/desorption isotherm. This study explored the removal efficiency of pharmaceutical tolperisone hydrochloride (TLP), as well as the herbicides quinmerac (QUI) and clomazone (CLO) from water, using dried and calcined LDH-based photocatalysts under simulated solar irradiation and UV irradiation. A higher removal efficiency was observed using UV irradiation, for all substrates. The most effective removal was achieved using ZnAl photocatalysts thermally treated at 100 °C (ZnAl 100) and 500 °C (ZnAl 500). The highest removal rates were observed in the TLP/ZnAl 100 and QUI/ZnAl 100 systems, achieving ~79% and ~86% removal after 75 min of treatment under UV. In contrast, the CLO/ZnAl 100 and CLO/ZnAl 500 systems achieved ~47% removal of CLO. Furthermore, this study investigated the role of reactive species to elucidate the mechanisms of photodegradation under UV. It was found that in the degradation of TLP and QUI in the presence of ZnAl 100 and ZnAl 500, the superoxide anion radical played the most important role.