采用共沉淀法合成了结晶度良好、具有纯水滑石相的Mg-Al型层状双金属氢氧化物(LDH)及其乙二胺四乙酸二钠(EDTA)-LDH无机-有机杂化物,并进行了表征.考察了Mg-Al LDH和EDTA-LDH对Pb~(2+)的吸附作用,其均有很好的吸附能力,EDTA在LDH通道中可能以直立平行方式排列成单层.在相同条件下,EDTA-LDH的吸附速率和吸附量均高于Mg-Al LDH.结果表明,EDTA的插入具有协同增效作用, 吸附动力学符合准二级吸附速率方程.吸附等温线可分为吸附阶段和表面沉淀阶段,吸附阶段的等温线符合Freundlich吸附等温式.初始pH值对Pb~(2+)的吸附基本无影响.Pb~(2+)在LDH和EDTA-LDH上的吸附机理主要为表面沉淀,并存在化学键合和静电键合作用,EDTA-LDH存在EDTA与Pb~(2+)的络合作用.
Well crystalled MgAl-layered double hydroxide(MgAl-LDH) and EDTA-LDH nanohybrids were synthesized via a co-precipitation method and characterized. The ligand EDTA is probably accommodated in vertical position in the interlayer space of LDH. The sorption behavior of MgAl-LDH and EDTA-LDH nanohybrids for lead ions was also investigated as a function of concentration, pH and time. It is found that both of them show good sorption ability for Pb~(2+). The sorption rate and the equilibrium sorption amount of Pb~(2+) are higher on EDTA-LDH nanohybrids than on MgAl-LDH under identical conditions, which indicate the intercalation of EDTA exhibits synergy. The sorption can be described by the pseudo-second order kinetics. The sorption occurrs in two steps, an adsorption process followed by surface precipitation. The adsorption isotherms are well fitted to Freundlich isotherm. Within the experimental concentration range, the variation of adsorbed amount is not obvious with the variation of pH because of the compound having a property of buffering pH(buffering pH effect).
参考文献
| [1] | Ulibarri M A,Pavlovic I,Barriga C,Hermoson M C,Cornejo J.Appl Clay Sci[J],2001,18(1):17 |
| [2] | Meyn M,Beneke Lagaly G.Inorg Chem[J],1990,29(26):5 201 |
| [3] | Miyata S.Clay Clay Miner[J],1980,28(1):50 |
| [4] | Hermoson M C,Pavlovic I,Ulibarri M A,Cornejo J.Wat Res[J],1996,30(1):171 |
| [5] | Gutmann N H,Spiccia L,Turney T W.J Mater Chem[J],2000,10(2):1 219 |
| [6] | Li C,Wang G,Evans D G,Duan X.J Solid State Chem[J],2004,177(12):4 569 |
| [7] | Tarasov K A,O'Hare D,Isupov V P.Inorg Chem[J],2003,42(6):1 919 |
| [8] | Zhang S Q Hou W G.Chinrdr J Chem[J],2007,25(10):455 |
| [9] | Pérez M R,Pavlovic I,Barriga C,Cornejo J,Hermosín M C,Ulibarri M A.Appl Clay Sci[J],2006,32(3/4):245 |
| [10] | Kanezaki E.Solid State Ionics[J],1998,106(4):279 |
| [11] | Yang W,Kim Y,Liu P K T,Sahimi M,Tsotsis T T.Chem Eng Sci[J],2002,57(15):2 945 |
| [12] | Wan W S,Kamari N A,Koay Y J.Int J Biol Macromol[J],2004,34(3):155 |
| [13] | Bradl H B.J Colloid Interface Sci[J],2004,277(1):1 |
| [14] | Reed B E,Cline S R.Sep Sci Technol[J],1994,29(12):1 529 |
| [15] | Pérez M R,Pavlovic I,Barriga C,Cornejo J,Hermos n M C,Ulibarri M A.Appl Clay Sci[J],2006,32(3/4):245 |
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