Adsorption Of Arsenic In Drinking Water By Rare Earth Modified Alumina Particles

The problem of arsenic pollution has already caused the concern of the society and the whole world. In order to solve the arsenic pollution in drinking water, many researchers have already started the relevant work. The adsorption methods and adsorbents are in the process of gradual improvement. Alumina as an adsorbent of arsenic has many good properties, but its adsorption capacity has some limitations. Modified can significantly improve the alumina adsorption properties of arsenic. Traditional aluminum oxide used for arsenic treatment mostly in powder forms which into drinking water treatment and industrial applications have some limitations. To solve these problems, this subject proposed to use spherical alumina particles as an adsorbent material. This paper intends to use rare earth metals adopted on alumina by an equal volume impregnation method to improve its adsorption properties. Particulate alumina has a certain mechanical strength, not flowing with the fluid, and will not produce secondary pollution to the environment.The static adsorption experiments results showed that the adsorption process on adsorbents before and after the modified are in line with the Langmuir equation, and the reaction kinetic equation was in accordance with quasi-second-order kinetic equation. The reaction was in accordance with the single molecular layer adsorption process, and there was a certain correlation between the adsorption rate and the concentration. In addition, the adsorption process also consistent with Elovich model and Bangham diffusion model, which fit R2>0.9. As the temperature increases, the adsorbents for arsenic removal rate increases, according to the adsorption thermodynamic analysis ΔS0>0 in adsorption before and after. That adsorption process of the temperature elevated belongs to the process of entropy increase and the confusion degree increases.ΔG0 values decreased gradually with increasing temperature indicating that the reaction processed tends to be spontaneous reaction. In addition, when the rare earth element loading with 15%, the maximum adsorption capacity of arsenic is 11.23 mg/g, a specific surface area of the modified adsorbent is 213.21-249.83 m2/g. In addition, we have a preliminary discussion on the adsorption mechanism of the adsorbent. It was found that the pH value has a great influence on the adsorption properties of the material, combined with CO2-TPD and XPS characterization and analysis, we found that the basic site of the material surface is a major factor affecting the adsorption performance.Fixed bed adsorption experiment results show that the dynamic adsorption process is affected by particle size, flow rates, bed height, initial concentration and so on. Through modification the breakthrough time can be extended to a large extent, and the drinking water quality standards have been achieved. It is proved that the rare earth modified alumina particles are feasible for the treatment of arsenic in drinking water.