The semiconductor, electroplating, metallurgy, and ceramic industries discharge high concentration fluoride containing wastewater, making fluoride pollution in natural water a global problem.Thus， Zn?Mg?Al LDO is a good adsorbent material. Under different reaction temperatures of n（Zn²⁺）/n（Mg²⁺）/n（Al³⁺）, Zn?Mg?Al LDH was synthesized by co?precipitation method, and Zn?Mg?Al?LDH was calcined at different temperatures to obtain Zn?Mg?Al?LDO. X?ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT?IR) and BET specific surface area testing methods were used to study the structure and properties of Zn?Mg?Al LDO. The adsorption experiment was conducted on 50 mL of NaF solution with an mass concentration of 20.0 mg/L to investigate the performance of Zn?Mg?Al LDO in adsorbing and removing fluoride ions. The results showed that the Zn?Mg?Al LDO prepared under the conditions of n（Zn²⁺）/n（Mg²⁺）/n（Al³⁺）=2∶1∶1, reaction temperature of 75 ℃, and calcination temperature of 400 ℃ exhibited the best adsorption and removal performance of fluoride ions, with an adsorption and removal rate of 85.39%. Zn?Mg?Al LDO has characteristic peaks of hydrotalcite, good crystal structure, and a layered structure. Zn?Mg?Al LDO is a mesoporous material with a specific surface area of 103.15 m²/g. In addition, the kinetics and adsorption mechanism of the adsorption process were also studied. The results indicate that the adsorption process follows the Langmuir adsorption isotherm and quasi second?order kinetic equation.

Layered double hydroxides (LDHs),also known as hydrotalcite,can be widely employed in water pollution treatment because of their special layered structures,high physicochemical stability,and electronic properties.The application of LDH composites as catalysts for photocatalysis has received increasing attention.Therefore,the preparation and modification of LDH photocatalysts were reviewed,and the removal effect of pollutants from wastewater exerted by different LDHs was emphatically introduced.In addition, the mechanism and research status of LDH photocatalysts were briefly described.Finally,the development trend of LDH photocatalysts was prospected to provide a reference for the subsequent application of LDHs in water pollution treatment.

Industrial wastewater is mainly composed of sewage and waste liquid produced in industrial production process, which has been characterized by its complex composition, wide variety, large difference and difficulty in treatment.The commonly used methods for preparation of hydrotalcite were reviewed, such as chitosan method, plasma method and agricultural waste method. Hydrotalcite materials in the adsorption process are mostly in powder, which is difficult to be recycled, and rarely used in industry applications. In view of the above problems, Fe ions can be introduced in hydrotalcite materials to generate magnetism, which is be beneficial to recovery. By developing cheaper synthetic materials, simple and fast preparation methods, stable physical and chemical properties of hydrotalcite materials, industrial applications could be achieved. The introduction of magnetic materials into hydrotalcite composites can help to recycle. With the in?depth study of hydrotalcite preparation technology, the prospect of dealing with toxic pollutants will be better.