| 杨孟娟,林建伟,詹艳慧,王春峰,储 鸣,李 佳,郑雯婧,方 巧.锆改性沸石活性覆盖控制重污染河道底泥氮磷释放研究[J].农业环境科学学报,2013,32(12):2460-2470. |
| 锆改性沸石活性覆盖控制重污染河道底泥氮磷释放研究 |
| Releases of Ammonium and Phosphorus from River Sediments Capped with Zirconium-Modified Zeolite |
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| DOI：10.11654/jaes.2013.12.020 |
| 中文关键词: 底泥 锆改性沸石 活性覆盖 氮磷 释放 控制 |
| 英文关键词: sediment zirconium-modified zeolite active capping nitrogen and phosphorus release control |
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| 摘要点击次数: 1933 |
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| 中文摘要: |
| 通过实验考察了锆改性沸石对水中磷酸盐和铵的吸附去除作用，并考察了锆改性沸石活性覆盖控制底泥溶解性磷酸盐和铵释放的效率。锆改性沸石对水中磷酸盐的吸附能力随pH值的增加而降低：当pH值由4增加到5时，锆改性沸石对水中铵的吸附能力增加；当pH值 5~8时，对铵的吸附能力较高；当pH值由8增加到10时，对铵的吸附能力下降。锆改性沸石对水中磷酸盐和铵的吸附动力学满足准二级动力学模型，并且对磷酸盐和铵的吸附速率比较快。Langmuir和Freundlich等温吸附模型可以用于描述锆改性沸石对水中磷酸盐和铵的吸附平衡数据，根据Langmuir模型计算得到的锆改性沸石对水中磷酸盐和铵的最大吸附量分别为7.75 mg·g-1和9.59 mg·g-1（pH 7和25 °C）。锆改性沸石对水中磷酸盐和铵的去除率随锆改性沸石投加量的增加而增加，其吸附水中磷酸盐的主要机制是配位体交换，吸附水中铵的主要机制是阳离子交换。被锆改性沸石所吸附的磷酸盐大部分（82.5%）以较为稳定形态磷（NaOH-P）存在，低溶解氧条件下不容易重新被释放出来。吸附磷酸盐后锆改性沸石中水溶性磷（WSP）、易解吸磷（RDP）和NaHCO3可提取态磷（Olsen-P）含量非常低，藻类可利用磷（AAP）含量仅占总磷含量的29%左右。低溶解氧条件下，重污染河道底泥会释放出大量的溶解性磷酸盐和铵，锆改性沸石活性覆盖则不仅可以使上覆水中的溶解性磷酸盐浓度控制到很低的水平，而且可以明显降低铵由底泥向上覆水迁移的速率。上述实验结果表明，锆改性沸石适合作为一种活性覆盖材料用于控制底泥溶解性磷酸盐和铵的释放。 |
| 英文摘要: |
| Nitrogen and phosphorus releases from river sediments greatly impact the quality of river water. So far there is still lack of effective means to reduce their releases. Batch and sediment incubation experiments were carried out to examine the efficiency and mechanism of zirconium-modified zeolite（ZrMZ） to reduce phosphate and ammonium releases from the sediments from heavily polluted river after capping with ZrMZ. Phosphate adsorption capacity by ZrMZ decreased with increasing pH. Ammonium adsorption capacity by ZrMZ increased slightly from pH 4 until 8, but decreased from pH 8 to 10. The adsorption kinetics of phosphate and ammonium on ZrMZ was found to follow a pseudo-second-order model. The equilibrium adsorption data of phosphate and ammonium on ZrMZ could be described by the Langmuir and Freundlich isotherm models. The maximum adsorption capacity of phosphate and ammonium on ZrMZ derived from the Langmuir isotherm model was 7.75 mg·g-1 and 9.59 mg·g-1 at pH 7 and 25 ℃, respectively. The removal efficiency of phosphate and ammonium by ZrMZ increased with adsorbent dosage. Phosphate adsorption onto ZrMZ was mainly via ligand exchange, while ammonium adsorption through cation exchange. About 82.5% of phosphate adsorbed onto ZrMZ existed as NaOH-P（Phosphorus extracted by NaOH） form, and was relatively stable and unlikely to be released under low dissolved oxygen conditions. Of total phosphorus adsorbed onto ZrMZ, percentages of water-soluble phosphorus（WSP）, readily desorbable phosphorus（RDP）, and NaHCO3 extractable phosphorus（Olsen-P） were very low and algal available phosphorus（AAP） accounted for only 29%. Capping sediments with ZrMZ not only prevents PO3-4-P and NH+4-N releases from the sediments, but significantly reduces PO3-4-P and NH+4-N concentrations in the overlying water. |
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