碳纳米管吸附水溶液中双酚A的热力学

以甲醇和去离子水组成的体系（体积比90∶10）为流动相,建立了以香烟过滤嘴作吸附剂，固相萃取（SPE）与高效液相色谱（HPLC）联用测定水中双酚A(Bisphenol A，BPA)的新方法。研究了水溶液中碳纳米管(CNTs)吸附双酚A的热力学特性，测定了不同温度下的吸附等温线，并探讨了其可能的吸附机理。结果表明，CNTs对BPA 的吸附主要以快速吸附为主，常温下，碳纳米管对于70 mg·L-1的双酚A水溶液的吸附量可达到 24.65 mg g-1，吸附量随初始浓度的增加而增加，随温度的降低而增大，采用Freundlich和Langmuir方程拟合，相关系数均大于0.99，热力学函数ΔG、ΔH及ΔS分别为-39.48 ~ -43.51 KJ·mol-1、-18.06 KJ·mol-1、71.73 J·mol-1·K-1，吸附为放热、熵增的自发过程，降低温度有利于吸附，并且具有物理吸附特征。

Determination of Bisphenol A and its adsorption on carbon nanotubes

A new method was established for the determaination of Bisphenol A (BPA) in water by solid-phase extraction (SPE) using the cigarette filter as sorbent coupled with high-performance liquid chromatography(HPLC).The mobile phase was methanol- deionized water (90：10 in volume ratio). The thermodynamics properties and mechanism of sorption process were studied for Bisphenol A on carbon nanotubes (CNTs) in aqueous solution and the adsorption isotherms at different temperstures were determined.The results showed that quick adsorption played a primary role in the adsorption of BPA on CNTs.The adsorption amount of BPA aqueous solution with a concentration of 70 mg·L-1 on CNTs reached 24.65 mg·g-1 under normal temperature which increased with increasing of initial concentration or dropping of temperature.The correlation coefficients were larger than 0.99 when both Langmuir equation and Freundlich equation were used to fit data. Thermodynamic functions such as ΔG,ΔH and ΔS are -39.48KJ·mol-1~-43.51KJ·mol-1,-18.06KJ·mol-1 and 71.73 J·mol-1·K-1,respectively. The adsorrption proved to be a spontaneous process having a character of physical adsorption. In addition, lower temperature was available to accelerate adsorption.