ANAMMOX颗粒污泥吸附氨氮特性及其影响因素

为了解析ANAMMOX颗粒污泥对氨氮的吸附特性及机理,分别考察了不同初始氨氮浓度和污泥浓度下的ANAMMOX颗粒污泥吸附氨氮特性,以及温度、p H、盐度和金属阳离子对氨氮吸附的影响;并采用了吸附等温式、动力学和热力学对吸附过程进行解析.结果表明,ANAMMOX颗粒污泥对氨氮的吸附在20min左右基本达到吸附平衡,吸附容量随着氨氮初始浓度的增加而增加,随ANAMMOX颗粒污泥浓度的升高而减少.低温有利于ANAMMOX颗粒污泥对氨氮的吸附,其最佳p H为7.0.盐度和金属阳离子显著影响ANAMMOX颗粒污泥对氨氮的吸附,在Na Cl浓度为5g/L时,吸附作用已不明显.在质量浓度相同的条件下,Fe3+对吸附作用抑制最强,Mg2+与Ca2+次之,而Cu2+相对最弱.ANAMMOX颗粒污泥吸附氨氮过程更符合Freundlich等温式,吸附过程符合准二级动力学模型,并且是由表层扩散和内部扩散共同作用的结果.热力学研究表明,该吸附过程是一个自发的放热过程.

Characteristics and influence factors of ammonia adsorption by ANAMMOX granular sludge

In order to explore the characteristics and mechanisms of ammonia adsorption by ANAMMOX granular sludge, the ammonia adsorption characteristics by ANAMMOX granular sludge in different initial ammonia concentrations and sludge concentrations, as well as the influences of temperature, pH, salinity and metal cations on the ammonia absorption were studied respectively; moreover, the adsorption isotherms, kinetics models and thermodynamics analysis were employed to investigate the adsorption process. Adsorption equilibrium was achieved in about 20minutes; the ammonia adsorption capacity was increased with the increasement of the initial ammonia concentration, however, showed a decline trend with the increasement of ANAMMOX granular sludge concentration; low temperature was in favor of ammonia adsorption; the optimal pH was 7.0. Salinity and metal cations had an obvious affect on the ammonia adsorption: when the concentration of NaCl was 5g/L, the ammonia adsorption process was inhibited completely almost; under the same mass concentration, Fe³⁺ showed the strongest inhibition effect, Mg²⁺ and Ca²⁺ took the second place and Cu²⁺ was the weakest relatively. The ammonia adsorption process by ANAMMOX granular sludge was fitted to the Freundlich isotherm, and the adsorption process was in line with the pseudo-second-order kinetic model, moreover, was the combined results of surface diffusion and internal diffusion. Thermodynamic studies demonstrated that the adsorption process was a spontaneous exothermic process.