Removal of phenylalanine from water with calcined CuZnAl-CO3 layered double hydroxides

焙烧型CuZnAl双金属氢氧化物对水中苯丙氨酸的脱除(英文)

Cu-Zn-AI-CO3 layered double hydroxide （LDH）, with a Cu to Zn mole ratio of 5：1 and a （Cu＋Zn） to AI mole ratio of nearly 2, was prepared and its calcined product （CLDH） was obtained. Batch sorption studies were conducted to investigate removal of phenylalanine from water with CLDH. The results show that CLDH can be used as an effective adsorbent and its sorption capacity is higher than that of Mg-A1--CO3-LDH. The maximum adsorption was observed at pH 6.7. A maximum adsorption capacity is 37.25 mg/g. The adsorption processes follow the Lagergren＇s first order kinetic model. The adsorption data are fitted well with the Langmuir isotherm equation. The thermodynamic parameters were calculated, and the negative △G and positive △H indicate that the adsorption processes are spontaneous endothermic in nature. The mechanism of adsorption also suggests that the benzoate molecules are tilted, forming an angle with the hydroxyl layers.

用水热法合成了Cu-Zn-Al-CO3双金属氢氧化物n(Cu)/n(Zn)=5,[n(Cu)+n(Zn)]/n(Al)≈2,简写为LDH),加热煅烧后得到焙烧型Cu-Zn-Al-CO3-LDH(CLDH),再采用批处理实验用其对模拟废水中的苯丙氨酸进行吸附。结果表明,CLDH对于废水中的苯丙氨酸是一种有效的吸附剂,其吸附效率明显高于同等条件下的LDH,当水相pH为6.7时,其吸附效率最高,吸附容量达到37.25mg/g。该吸附过程符合Lagergren准一级动力学模型,同时其平衡吸附等温线能很好地符合Langmuir等温方程,通过对吸附热力学研究发现,△GΘ计算值为负,△HΘ计算值为正,这表明此类吸附本质上为吸热自发过程。吸附机理表明苯甲酸分子在层间是倾斜的,与羟基层形成了一个角度。