13X分子筛涂层制备及用于脱除丹参中铅和镉

Preparation of 13X Zeolite Film and Its Application for Removal of Lead and Cadmium in Salvia Miltiorrhiza

运用预涂溶胶、低温干燥、合成液中晶化生长的方法,在α-Al2O3陶瓷管表面制备了13X分子筛涂层,优化得到了n(Al_2O_3)∶n(SiO_2)∶n(Na_2O)∶n(H_2O)=1.00∶3.50∶7.88∶630的合成液,考察了制备条件对13X分子筛涂层的影响。结果表明:只有预涂溶胶的α-Al2O3陶瓷管表面可得到连续均匀的分子筛涂层,且预涂溶胶法比凝胶法更有利于制得连续的13X分子筛涂层。当溶胶干燥温度为35~45℃,干燥时间为12~18 h时,XRD、SEM测试结果表明,陶瓷管表面可以得到结晶性较好的连续涂层。将上述13X分子筛涂层0.12 g用于丹参提取液(铅和镉的质量浓度均为2 mg/L)中铅和镉的脱除,脱除率分别可达86.7%和44.2%。经过13X分子筛涂层净化后的丹参提取液含固量、丹酚酸B和迷迭香酸保留率分别为99.6%、96.8%、99.3%,与13X分子筛颗粒净化后的丹参提取液相比无明显变化。丹参提取液处理前后的高效液相指纹图谱相似度接近100%。

13X zeolite films on α-Al2O3 ceramic tube were prepared by using a method of pre-coating sol, then drying in lower temperature and finally crystallizing in synthetic solution. The optimal molar ratio of oxides in synthetic solution was n （ Al2O3 ） ： n （ SiO2 ） ： n （ Na2O ） ： n （ H2O ） = 1.00 ： 3.50：7.88： 630. The influences of preparation conditions on formation of 13X zeolite films were also investigated. The results showed that continuous and uniform films on α-Al2O3ceramic tube could be obtained only by pre-coating sol method. The pre-eoating sol method was more suitable for the preparation of continuous films than the pre-coating gel method. XRD and SEM results revealed that when the precoating sol was dried in the range of 35 -45 %] for 12 - 18 h,the regular crystals and continuous films were formed and coated on the surface of ceramic tube. Subsequently,the as-prepared 13X zeolite film （0.12 g） was used to remove lead and cadmium in salvia miltiorrhiza extract （mass concentration of lead and cadmium were both 2 mg/L）. It was found that the removal rates of lead and cadmium were 86. 7% and 44.2% , respectively. After purification of salvia miltiorrhiza extract, the retention rates of solid content,salvianolie acid B and rosmarinie acid were 99.6% ,96. 8% and 99.3% , respectively. During the removal process, 13X zeolite film did not obviously change the active ingredients in salvia miltiorrhiza extract compared with 13X zeolite particles. Meanwhile, HPLC fingerprint similarity of salvia miltiorrhiza extract approached 100% before and after removal of lead and cadmium.