Effect of inorganic salt modification on zeolite barriers to control phosphorus and nitrogen release from sediments

通过试验, 考察了无机盐改性对沸石覆盖控制底泥氮磷释放效果的影响, 并对沸石覆盖技术控制底泥氮磷释放的机理进行初步探讨, 结果表明:①NaCl及CaCl₂改性对沸石吸附氨氮的性能影响不大;CaCl₂改性可以提高沸石Ca²⁺的交换量而降低Na⁺的交换量, NaCl改性则可以明显降低Ca²⁺的交换量和增加Na⁺的交换量.②NaCl及CaCl₂改性对沸石覆盖技术控制底泥氨氮的释放影响不大, 而对控制底泥磷的释放则影响较大, 沸石覆盖控制底泥磷释放效率从大到小依次为CaCl₂改性沸石>天然沸石>NaCl改性沸石.③沸石覆盖技术控制底泥氨氮释放的机理为沸石的物理吸附和阳离子交换作用, 控制底泥磷释放的机理包括沸石的机械阻挡作用和沸石与铵所交换出来的Ca²⁺对磷酸盐的固定作用.;Effect of inorganic salt modification on efficiency of zeolite barrier to control phosphorus and nitrogen release from sediments was analyzed.The results show that :( 1) Sorption of ammonium on zeolite was influenced less by modification of NaCl or CaCl₂.However, in comparison to natural zeolite, NaCl modification zeolite will release more Na^+ and less Ca²⁺, and CaCl₂ modification zeolite will release less Na⁺ and more Ca²⁺.(2) The efficiency of zeolite barrier to control ammonia release will be influenced little by modification of NaCl or CaCl₂.However, the efficiency of zeolite barrier to control phosphorus release will be greatly affected by modification of NaCl or CaCl₂, and in order of CaCl₂ modification zeolite > natural zeolite > NaCl modification zeolite.(3) The mechanics of zeolite barrier for controlling ammonia release is physical sorption and ion exchange, and zeolite barrier reduces phosphorus release rate depends on its trapping and immobilization of Ca²⁺ that was released from zeolite.