| 改性与成型层状氢氧化镁铝对不同水体中PO43- 的脱除性能 |
| 摘要点击 2485 全文点击 1631 投稿时间：2012-06-14 修订日期：2012-08-02 |
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| 中文关键词 改性与成型 层状氢氧化镁铝 PO43- 水溶液 废水 海水 脱除 |
| 英文关键词 modification and granulation magnesium and aluminium layered double hydroxide PO43- water solution wastewater seawater removal |
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| 中文摘要 |
| 利用大型工业设备制备出性能稳定的粉末层状氢氧化镁铝(500 kg·批-1,记为Mg-Al LDH),采用沉积法将Mg-Al LDH进行改性与成型,研究了改性与成型层状氢氧化镁铝(记为MG Mg-Al CLDH)对水溶液、废水、不同地带海水中PO43-的动态吸附脱除及再生性能. 结果表明,MG Mg-Al CLDH能够有效脱除不同水体中的PO43-,满足污水综合排放一级标准或海水水质一级标准. MG Mg-Al CLDH 对PO43-脱除主要是通过离子交换和"结构记忆"效应共同实现的. MG Mg-Al CLDH对水溶液中PO43-的穿透吸附量是未改性时的6倍以上,再生率为126.24%,PO43-的穿透曲线受固定床高度、流量、溶液初始浓度、溶液初始pH值的影响,液膜扩散是吸附过程的主控步骤. 当溶液初始浓度低至4.61 mg·L-1时,MG Mg-Al CLDH能将某污水处理厂二级出水中PO43-有效脱除,满足污水综合排放一级标准. 当PO43-浓度低至0.38 μmol·L-1,MG Mg-Al CLDH仍能将其从海水中有效脱除,达到海水水质一级标准,为解决Mg-Al LDH在实际应用中存在粉末易堵塞床体、无法实现固液分离和再生的问题及水体中磷的脱除提供了一条新型可行之路. |
| 英文摘要 |
| Powder layered double hydroxide of Mg-Al LDH were prepared by hydrothermal technology with 500 kg·batch-1, modified and granulated (MG Mg-Al CLDH) by deposition method. After the modification and granulation, the fixed bed can not be accumulated and clogged by the adsorbents. The PO43- is removed from aqueous solution, wastewater and seawater by MG Mg-Al CLDH with column experiments. It shows that MG Mg-Al CLDH is an effective adsorbent. After removal, the water quality can satisfy with the first degree of integrated wastewater discharge or seawater standards. The mechanism of removal PO43- is ion exchange and 'memory effect’. The breakthrough adsorption capacity of PO43- from solution is 13.49 mg·g-1, more than 6 times higher than that by Mg-Al LDH without modification. The exhausted MG Mg-Al CLDH can be desorbed with 0.1 mol·L-1 NaOH and 3 mol·L-1 NaCl and regenerated with 25% MgCl2. The regeneration rate is 126.24%. The breakthrough curves are influenced by bed depth, flow rate, initial concentration and initial pH. The adsorption processes are controlled by film diffusion. When the initial concentration is as low as 0.38 μmol·L-1, PO43- can be removed from seawater to satisfy with the first degree of seawater quality. So this work is very useful for the practical application of Mg-Al LDH and the removal of phosphorus. |
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