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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.

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.

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.

In this study, the background subtraction of cyclic voltammetry of a low oxidation peak at NiO based electrode is employed for the determination of glucose in human serum in 0.1 M NaOH medium with 2 linear ranges of 10 to 100 μM and 100 to 2000 μM with a detection limit of 2 μM and sensitivities of 2942.2 and 754.2 μAcm-2mM-1, respectively. As a result, determining the glucose concentration in the real sample shows that this type of NiO-based sensor can be used in practice and approach to accurately determining the glucose concentration in human serum.