| Uranium is often in the form of UO22+migration in soil，water, cause seriousharm to animals and plants as well as the human body. It is significant to develop aneconomic and efficient containing uranium wastewater treatment. Adsorption methodis simple, high effect and the absorbents can be reused, which has always been thefocus of the research in water treatment. In recent years, It is focus on looking for lowcost adsorbent to instead of the widely used activated carbon.Humic acid containplenty of functional groups, which can reaction with UO22+complexation. Attapulgiteis a kind of natural mineral raw material, uranium sources, low prices, has thestronger adsorption ability. Therefore, the research adopt physical and chemicalmethods to modify HA and ATP, and then discusses IHA and HA/ATP influencingfactors and adsorption mechanism of adsorption of uranium in the waste water.The adsorption experiments were researched by using humic acid (IHA)Modified as the adsorbent to remove the U(Ⅵ) from contained-uranium wastewater.The effect of pH, contact time, initial concentration, temperature and dosage ofadsorbent on the U(Ⅵ) removal process were evaluated. The adsorption wereanalyzed by kinetics, thermodynamics and adsorption isotherm law, and mechanismsfor U(Ⅵ) removal were discussed by SEM, FTIR. Thermodynamic parametersrevealed the feasibility, spontaneity and exothermic nature of adsorption. The processof adsorption fits to Freundlich isotherm. The process of adsorption also can bedescribed by an equation of pseudo2nd-order mode. SEM displayed that theadsorption of U(Ⅵ) on IHA changes the surface form of IHA, while FTIR revealedthat the main functional groups in the reaction with U(Ⅵ) are phenolic hydroxyl,carboxylic. The mechanism for the removal of U(Ⅵ) ions by IHA was based on anion exchange reaction.Humic acid/Attapulgite (HA/ATP) was prepared with natural Humic acid andAttapulgite. HA/ATP was used as the adsorbent to remove the U(Ⅵ) fromcontained-uranium wastewater. Fourier transform infrared Spectrum (FTIR) ofHA/ATP before and after modification show that coating is successful and modification is effective. SEM analysis before and after adsorption indicates thatU(Ⅵ) is adsorbed successfully onto the HA/ATP. The influences of the pH of solution,the initial concentration of U(Ⅵ) ions and the contact time on the adsorption amountsare discussed, and appropriate process conditions for the adsorption of U(Ⅵ) areobtained. The process of adsorption fits well with Langmuir, Freundlich and Temkinisotherm; The process of adsorption also can be described by an equation of pseudo2nd-order mode. Adsorption rate is controlled by liquid film diffusion and particlediffusion, and high concentration is mainly controlled by particle diffusion.Thermodynamic parameters revealed the feasibility, spontaneity and endothermicnature of adsorption. |
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