月桂酸钠有机表面改性凹凸棒石

Organic surface modification of attapulgite with sodium laurate

采用化学沉淀法以偏铝酸钠为原料在凹凸棒石(AT)表面包覆氧化铝,然后用月桂酸钠对凹凸棒石进行有机表面改性。采用XRD、FTIR、TG-DTA、活化指数、接触角和分散性实验等对改性样品进行了表征。结果表明,氧化铝和月桂酸钠的适宜用量分别为:m(Al2O3):m(AT)=1.5∶10,m(C11H23COONa)∶m(AT)=1.5∶10。XRD表明氧化铝水合物以无定形结构包覆在凹凸棒石表面。FTIR表明月桂酸根以物理吸附的方式附着于凹凸棒石的表面。当m(C11H23COONa)∶m(AT)≤1.5∶10时,随着月桂酸钠用量的增加,凹凸棒石表面吸附月桂酸根的量逐渐增大,所得样品的活化指数和与水的接触角逐渐升高;当m(C17H35COONa)∶m(AT)≥1.5∶10时,月桂酸根已将凹凸棒石表面完全包覆。分散性实验表明,经月桂酸钠表面改性的凹凸棒石由亲水性变成了疏水性。

The surface organic modification of attapulgite with sodium laurate, which was pre-coated with aluminum oxide by chemical precipitation method using sodium aluminate as raw material, was studied. The as-prepared samples were characterized by Fourier transform infrared spectra （FTIR）, thermogravimetry（TG）, differential thermal analysis（DTA）, activation index and dispersivity experiment, respectively. The results showed that the suitable mass ratio of aluminum oxide and sodium laurate were ascertained as： m（Al2O3） ： m（AT） = 1.5： 10, m（C11H23COONa）：m（AT） =1. 5： 10. XRD revealed that aluminum oxide on the surface of attapulgite was amorphous. FTIR indicated the interaction between attapulgite surface and laurate radical was physical adsorption. When m（C11H23COONa） ： m （AT） ≤ 1.5：10, the mass fraction of physisorbed laurate radical, contact angle and activation index of attapulgite was increased with m （C11H23COONa） ： m （AT）. The surface of attapulgite was wholly coated with laurate radical ,while m（C11H23COONa） ： re（AT ） ≥ 1.5 ： 10. The dispersivity experiments showed that the surface property of attapulgite modified with sodium laurate was changed from hydrophilicity to hydrophobicity.