The co-precipitation method was employed to synthesize a set of ZnAl hydrotalcite materials modified by Cu²⁺. The synthesized materials have a similar lamellar structure to that of hydrotalcite. The distance between layers is in the range of 7.73–8.56 Å. The network parameters a and c ranged from 3.058 to 3.074 Å and from 23.01 to 24.44, respectively. According to the IUPAC classification, the composites possess a mesoporous structure which belongs to class IV, type H 3. Particularly, the absorption edge shifts strongly to the visible light region when increasing the molar ratio of Cu²⁺ in the samples from 0 to 3.5. The photocatalytic activity of the synthetic materials was evaluated through the degradation efficiency of rhodamine-B (Rh-B) in the water and colorants in textile wastewater. The present study was the first to synthesize a material sample that contains a molar ratio of Cu²⁺ in the range of 2.5–3.5 and has high catalytic activities. They were able to degrade Rh-B at a high concentration (100 ppm) with a conversion rate of approximately 90% after 240 min of irradiation using a 30 W LED light. The catalytic activity of the composites depends on the molar ratio of modified Cu²⁺, the value of environmental pH, the H₂O₂ concentration and the irradiation time.

Cuprous oxide/copper/cupric oxide nanoparticles were synthesized through a hybrid process involving anodic dissolution and a controlled redox reaction between NaOH and glucose in the solution. The study demonstrates the structural manipulation of the material by varying the reaction components within the solution. Morphology, structural analyses using SEM (Scanning Electron Microscope), EDX (Energy-dispersive X-ray spectroscopy), TEM (Transmission Electron Microscope), FTIR (Fourier Transform Infrared Spectroscopy), XRD (X-ray diffraction), and XPS (X-ray photoelectron spectroscopy) unveiled the tunability of the material's structure based on the reaction components. Nitrogen adsorption analysis employing the Brunauer-Emmett-Teller (BET) equation confirmed the material's porosity, while Dynamic Light Scattering (DLS) measurements provided insights into the materials' hydrodynamic size and zeta potential. The results demonstrated that by increasing the glucose/NaOH ratio during the reaction, the different structures and morphologies of the distinct products were obtained from the clustering of small nanoparticles to cubic shape and flower-like structure. Antibacterial activity tests conducted on various bacterial strains showed a correlation between the morphology and structure of the material and its antibacterial properties. The highest substantial antibacterial efficacy against all tested bacterial strains at a dosage of 100 μg/L was obtained for the samples with clustering morphology, whereas the remaining materials showed no discernible antibacterial effect against one of the studied bacteria. The results also demonstrated that the sample with a clustering structure exhibited superior antibacterial properties when dispersed in water containing dimethylsulfoxide.

In this study, ZnO nanoparticles were fabricated by using the hydrothermal method for adsorption of phosphate from wastewater. The obtained ZnO nanorods were characterized by powder X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), specific surface area (BET) and energy dispersive X-ray spectroscopy (EDS). The ZnO materials were applied for adsorption of phosphate from water using batch experiments. The effects of pH (4–10), adsorption time (30–240 min), the amount of adsorbent (0.1–0.7 g/L) and initial concentration of phosphate (147.637–466.209 mg/L) on the adsorption efficiency were investigated. The optimum condition was found at pH = 5 and at an adsorption time of 150 min. The adsorption was fitted well with the Langmuir isotherm and the maximum adsorption capacity was calculated to be 769.23 mg/g. These results show that ZnO nanomaterial would highly promising for adsorbing phosphate from water. The adsorption of phosphate on ZnO nanomaterials follows the isothermal adsorption model of Langmuir, Tempkin and Freundlich with single-layer adsorption. There is weak interaction between the adsorbent and the adsorbate. Phosphate adsorption of the ZnO nanomaterials follows Lagergren’s apparent second-order kinetic model and was spontaneous and exothermic.

ZnAlCO₃ hydrotalcite materials modified by Cu²⁺ ions were synthesized by the co-precipitation method according to the molar ratios of (Cu²⁺ + Zn²⁺):Al³⁺ as 7:3. Thus, the modified materials contain various molar ratios of Cu²⁺ from 0–3.5 in the samples. The synthesized materials were characterized by X-ray diffraction pattern (XRD), FT–IR, EDS, SEM, the N₂ adsorption/desorption isotherm (BET), and UV–Vis DRS spectrum. The synthesized materials were characterized by a layered double hydroxide structure—such as hydrotalcite. The specific surface area BET increases slightly, corresponding to the increasing Cu²⁺ molar ratios, and the bandgap energy Eg decreases accordingly. Especially, these material samples have a high phenol red (PR) adsorption capacity at a concentration of 100 ppm and PR was degraded under a 30 W LED light with over 90% of conversion efficiency in the presence of 1.2 mL of 30% H₂O₂ solution. In addition, the CuH–3.5 material sample maintained stability after four times catalytic reuse. Therefore, this material can be used as an effective treatment for the wastewater of the sedge mat weaving village.

Dye-containing wastewater remains difficult to treat due to the persistence of synthetic dyes and the limitations of conventional adsorbents. In this study, a hierarchically porous activated carbon (ACLDP) was synthesized from Lansium domesticum peel via an integrated hydrothermal-H₃PO₄ activation strategy, yielding a mesopore-dominated structure enriched with oxygen-containing functional groups. Despite a moderate BET surface area (115.12 m² g⁻¹), the material exhibited a high adsorption capacity toward methylene blue (∼345.8 mg g⁻¹), suggesting that adsorption performance is influenced not only by surface area but also by pore accessibility and surface chemistry. A statistically rigorous model discrimination approach based on the Akaike Information Criterion (AIC), which remains less commonly applied in dye adsorption studies, was employed to evaluate nonlinear isotherm and kinetic models. The Sips model provided the best description of equilibrium data (R² = 0.9975, ΔAIC = 0), suggesting the relevance of surface heterogeneity in describing adsorption behavior. Kinetic analysis further indicated that no single model adequately captured the adsorption process, supporting a multi-step mechanism involving intraparticle diffusion and heterogeneous surface interactions. Mechanistic interpretation, supported by physicochemical characterization and adsorption behavior, suggests that electrostatic attraction, π–π interactions, hydrogen bonding, and pore diffusion collectively contribute to adsorption in a coupled and condition-dependent manner. These findings highlight that rational pore structure design and surface functionality can partially compensate for relatively low surface area, offering a viable strategy for converting agricultural residues into efficient carbon-based adsorbents. This study also provides a statistically supported framework for interpreting adsorption behavior, contributing to the development of sustainable materials aligned with circular economy principles.