制备方法对铜镁铝类水滑石吸附性能的影响

Effect of preparation method on adsorption properties of Cu-Mg-Al hydrotalcite-like compounds

为了考察制备方法对水滑石结晶形态及吸附性能的影响,同时解决吸附剂再生困难且易产生二次污染的问题,分别采用共沉淀法和水热法合成具有光催化作用的Cu-Mg-Al类水滑石,通过X射线衍射(XRD)、扫描电镜(SEM)、傅里叶变换红外光谱(FTIR)等方法对制备的材料进行了表征,考察了其对盐酸四环素(TC)的吸附性能,吸附饱和的类水滑石采用紫外光照再生。结果表明,共沉淀法合成的LDHs-C吸附性能优于水热法合成的LDHs-H,对TC的去除率分别为95.2%和75.2%。Cu-Mg-Al类水滑石吸附TC的过程均符合准二级动力学方程和Langmuir吸附等温模型。吸附饱和的吸附剂在紫外线照射下30 min即可实现再生,经4次循环后,LDHs-C对TC的吸附量仍能保持原有的90%以上。

In order to investigate the influence of synthesis methods on the crystal morphology and adsorption performance of hydrotalcite,and solve the problem of difficult regeneration of adsorbent and easily causing secondary pollution,Cu-Mg-Al hydrotalcite-like compounds(LDHs)with photocatalysis were synthesized by the coprecipitation method and the hydrothermal method,respectively,and the prepared materials were characterized by X-ray diffraction(XRD),Scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR)and other methods,the adsorption of tetracycline hydrochloride(TC)was investigated.The saturated hydrotalcite-like compounds were regenerated under UV light.The results show that the adsorption performance of LDHs-C synthesized by the coprecipitation method was better than that of LDHs-H synthesized by the hydrothermal method,their removal rates of TC were 95.2%and 75.2%,respectively.The adsorption process of Cu-Mg-Al hydrotalcite-like compounds conformed to the quasi second order kinetic equation and Langmuir adsorption isotherm model.The saturated adsorbent could be regenerated by 30min UV irradiation.After 4 cycles,the adsorption capacity of TC on LDHs-C could still maintain over 90%of the original.