HCl改性沸石和方解石复合覆盖层控制底泥氮磷释放的效果及机理研究

提出了HCl改性沸石和方解石复合覆盖控制底泥氮磷释放的新方法，利用摇床振荡试验和底泥氮磷释放控制模拟试验，设计了5种底泥处理方案，重点针对HCl改性沸石和方解石复合覆盖技术研究了其抑制底泥氮磷释放的效果及机理.结果表明，方解石覆盖层可以较好地抑制底泥磷的释放，而对底泥氨氮释放的抑制效果较差.天然沸石和方解石复合覆盖层不仅可以有效地抑制底泥氨氮的释放，而且可以有效地抑制底泥磷的释放.采用HCl对沸石进行改性，可以提高沸石和方解石复合覆盖层抑制底泥磷释放的效率，模拟期间复合覆盖层对底泥磷释放通量的抑制率由天然沸石的84%提高到HCl改性沸石的91%.采用HCl对沸石进行改性，降低了沸石和方解石复合覆盖系统有效控制底泥氨氮释放的持续时间，与天然沸石相比，相同投加量条件下HCl改性沸石有效控制底泥氨氮释放的持续时间缩短了1/3左右.采用HCl对沸石进行改性增强了复合覆盖系统抑制底泥磷释放效率的机理与HCl改性降低了沸石Na⁺的交换量并提高了沸石H⁺的交换量相关.

Efficiency and Mechanism of Compound Barrier with HCl Modification Zeolite and Calcite to Control Nitrogen and Phosphorus Release from Sediments

A novel compound barrier constructed with HCl modification zeolite and calcite was reported to control phosphorus and nitrogen release from sediments. Using short-term batch experiments and long-term sediment incubation experiments, the efficiency and mechanism of the compound barrier under anaerobic condition was investigated. For sediment incubation experiments, five kinds of active barrier conditions were applied respectively. The results showed that the calcite barrier reduced the phosphorus release from the sediment effectively, but not for the ammonia release from sediments. The compound barrier constructed with natural zeolite and calcite can reduce both the phosphorus and the ammonia release from sediments. In comparison to natural zeolite, the novel compound barrier constructed with HCl modification zeolite and calcite can control phosphorus released from sediments more effectively. Application of 40 g natural zeolite and 100 g calcite barrier resulted in 84% reduction of phosphorus flux from sediments for 80 days, but 91% reduction was obtained by compound barrier with 40 g HCl modification zeolite and 100 g calcite. In comparison with the natural zeolite, the duration of ammonia release control from sediments was shortened to two-thirds for the compound barrier with HCl modification zeolite. Reduction of Na⁺ and increment of H⁺ released from HCl modification zeolite were the possible reasons for the higher efficiency of the compound barrier to control the phosphorus release from the sediments.