茶叶渣对水溶液中Cu2+的吸附研究

为研究茶叶渣对水溶液中Cu2+的吸附及其机理，利用台湾高山茶叶渣对水溶液中Cu2+进行了吸附实验，考察pH、吸附时间、反应温度、Cu2+初始浓度等因素对吸附效能之影响。实验结果表明：台湾高山茶叶渣对Cu2+有很好吸附效果，吸附平衡时间约为60 min；随着反应温度增加，对Cu2+的吸附效能逐渐提高。在固定初始Cu2+浓度、吸附时间、震荡转速及反应温度下，pH会影响茶叶渣对Cu2+的吸附效能，pH 4时吸附效果最佳。对Cu2+的吸附效能均可使用Langmuir与Freundlich等温吸附方程式进行推估，但比较相关系数，前者较后者有更佳的推估能力；分别计算30、40和50℃下的吸附热力学参数，对应的吉布斯自由能(ΔG0)均为负，表明该反应自发进行；焓变(ΔH0)＞0，证实该反应为吸热反应；熵变(ΔS0)＞0，说明该吸附反应是熵增的过程；茶叶渣吸附前后的红外谱图分析，表明物理吸附为茶叶渣吸附Cu2+的主要机制。

Adsorption research of Cu2+ on tea dregs from aqueous solution

The adsorption properties and mechanism of Cu2＋ from aqueous solution using the tea dregs was studied In this paper,the adsorption experiments of Cu2＋ from aqueous solution using the Taiwan high mountain tea dregs as an adsorbent were carried out. The effects of various parameters such as initial pH,adsorption time,reaction temperature,and initial concentrations were investigated. The results indicated that the tea dregs had fine adsorption effects on Cu2＋ ion. The adsorption equilibrium time was 60 min. And the adsorption efficiency of Cu2＋ increased sharply as the reaction temperature increasing. The pH was important influence factors to adsorption and the optimum pH was 4. The adsorption data followed the Langmuir model and the Freundlich model. But the Langmuir model had the better correlation at different temperature. Thermodynamic parameters,including ΔG0,ΔH0,ΔS0were calculated. The values of ΔG0 at 30℃,40℃ and 50℃ were negative value,indicating the spontaneous nature. The positive value of ΔH0 revealed that the endothermic nature was existed in the tea dregs absorption process. The positive value of ΔS0 represents that the tea dregs adsorption was an increasing process for entropy. Also,the comparison of FTIR information after the Cu2＋ adsorption on teadregs with the initial tea dregs provided evidence of physical adsorption in the adsorption process.