双酸改性对低品位凹凸棒石吸附性能和白度的影响

以低品位凹凸棒石为原料,采用双酸活化法,对原料及酸改性样品进行了SEM、XRD、XRF、BET表征及分析,以其对大豆油的脱色率为性能评价,探讨了双酸改性对低品位凹凸棒石吸附性能和白度的影响规律。研究表明,低品位凹凸棒石的改性方法采用双酸活化法——先硫酸酸化再盐酸酸化,得到的样品对大豆油的脱色率为76.83%,达到国家标准值,白度也较高,为71.8%。低品位凹凸棒石原矿中含钙物质的杂质较多,硫酸改性后吸附性能没有得到明显提高,可能是由于微溶的硫酸钙残留在样品表面或孔隙中。此外,低品位凹凸棒石及酸改性样品对大豆油除了物理吸附外,还存在一定的化学吸附。

Effects of Double Acid Modification on Adsorbability and Whiteness of Low Grade Attapulgite

The low grade attapulgite was acidified with double acid and its properties before and after acidification were characterized by SEM, XRD, XRF and BET. Based on the decolorization rate of soybean oil, the effect of double acid modification on the adsorption performance and whiteness of attapulgite was studied. The results indicated that the decolorization rate of soybean oil by attapulgite which acidified by sulfuric acid then hydrochloric acid was 76.83%, reaching the international standards, and its whiteness was 71.8%. The low grade attapulgite contains a lot of calcium impurities, and its adsorption performance wasn’t significantly improved after sulfuric acid modification, which may due to the residue of slightly soluble calcium sulfate on the sample surface or in the pores. Besides physical adsorption to soybean oil, there was also a certain amount of chemical adsorption for the low grade attapulgite and its acid modified samples.