去除水中腐殖酸的磁性焙烧态类水滑石制备与表征

Preparation and Characterization of Magnetic Calcined Layered Double Hydroxides for the Removal of Humic Acid from Aqueous Solution

采用共沉淀法一步合成系列类水滑石负载磁性粒子的颗粒,经煅烧得到磁性焙烧产物。利用焙烧产物吸附水中腐殖酸,得到磁性焙烧态锌铝类水滑石去除腐殖酸效果较好。考察了磁性焙烧态锌铝类水滑石制备条件对腐殖酸去除效果的影响,通过正交试验优化了制备条件。静态吸附实验表明:吸附剂投加量0.2 g/L,30 min内20mg/L腐殖酸去除率为97.96%。X射线衍射(XRD)、红外光谱(FT-IR)、热重-差热(TG-DSC)和比表面积(SSA)表征结果表明:一定量的磁性基质掺入并没有破坏锌铝类水滑石典型的层状结构;焙烧态产物为氧化物,磁性保持良好;比表面积达80.00 m^2/g。磁性焙烧态锌铝类水滑石在水中因"记忆效应"而结构重建通过表面吸附和腐殖酸结构中小尺寸的官能团插层快速去除腐殖酸。

Magnetite particles were coated on layered double hydroxides by one-step co-precipitation method,then the prepared solids were calcined to obtain magnetic metal oxides, which were used to remove humic acid from aqueous solution. The results show that magnetic calcined Zn-Al LDHs （ M ·Zn- AlLDO） performed a effective adsorption for humic acid removal. The effect of preparation conditions on the removal of humic acid was investigated, and the preparation conditions were optimized by orthogonal test. The results of adsorption of humic acid by M· Zn-Al LDO show that the humic acid removal rate is obtained 97. 96% with the M ·Zn-Al LDO dosage of 0. 2 g/L at 30 min in initial humic acid concentration of 20 mg/L. The adsorbent is characterized using X-Ray, FT-TR, TG-DSC and SSA analysis, the results demonstrat that typical layered structure of hydrotalcite is not affected by introducing a certain amount of magnetic substrates which are Fe3 0 4 and γ-Fe2 0 3. The calcined products are metal oxides and still held excellent magnetic property, whose specific surface area is 80. 00 m2/g. The humic acid removal by M · Zn-Al LDO is performed by surface adsorption and intercalation of small size functional groups in humic acid when the structure of hydrotalcite built again on memory effect.