在紫外吸收光谱范围内对黄药溶液进行扫描, 发现在波长226.5和300 nm处有两个明显吸收峰, 且300 nm处的吸收峰强于226.5 nm处的。 采用标准曲线法对不同浓度的标准样品进行浓度测量, 对所得数据进行线性拟合, 结果表明: 在波长226.5和300 nm处的线性相关性均较好, 但在波长300 nm处的相关性更佳, 在226.5 nm处进行高浓度黄药溶液测量, 可在300 nm处进行低浓度黄药溶液测量。 在300 nm下对不同浓度黄药溶液进行定量分析, 结果表明, 最大吸光度为1.672, 最小吸光度为0.032时, 黄药溶液标准曲线的线性相关性仍很好, 吸光度继续增大时, 相关系数降低, 在进行定量分析时, 黄药浓度最好不要超过20 mg·L^-1。 在不同pH条件下, 在300 nm处对黄药溶液进行浓度测量, 发现pH为3时, 吸光度下降, 黄药开始分解, 当溶液pH为2时, 所测吸光度为0, 黄药已完全分解, pH值在5~10范围内, 黄铜矿对黄药吸附较好, 溶液最佳吸附pH值为9。 在300 nm处测量黄药在黄铜矿表面吸附量, 分别采用Freundlich和Langmuir等温吸附模型方程、 准一级和准二级动力学方程模型对所得实验数据进行拟合, 研究其在黄铜矿表面的吸附动力学和热力学。 结果表明: 在288~303 K范围内, 温度变化对吸附量多少影响不大, 黄药在黄铜矿表面的吸附等温线更符合Langmuir等温线模型, 黄铜矿对黄药的实际平衡吸附量 Q_e均小于或接近理论单层饱和吸附量, Q_m值均与实验值极为接近, 说明黄药在黄铜矿表面的吸附以单层化学吸附为主。 随着温度升高, 吸附量增加, 说明升高温度有利于吸附过程进行, 黄铜矿对黄药的吸附为吸热过程, 但吸附量增加幅度很小, 说明黄药在黄铜矿表面吸附受温度影响较小。 该吸附过程是一个熵增、 吸热、 自发进行的过程, 热力学参数可通过范特霍夫方程计算得到, 吸附焓变Δ H为48.703 41 kJ·mol^-1, 熵变Δ S为219.403 88 J·(mol·K)^-1, 吸附自由能变Δ G为-16.054 93 kJ·mol^-1, 推测该吸附过程属于化学吸附; 黄铜矿对黄药的吸附更符合准二级动力学方程模型, Q_t值随着温度升高而增大, 且变化幅度很小, 表明黄药在黄铜矿表的吸附过程为吸热过程, 但受温度变化较小, 这与热力学分析的结论一致, 对方程拟合所得 Q_e值均与实验值极为接近。

Spectrum scanning was conducted to characterize xanthate solution by Ultraviolet spectrophotometry. Two strong absorption peaks at the wavelength of 226.5 and 300 nm could be observed, respectively. And the absorption peak at 300 nm was stronger than that at 226.5 nm. Then, the standard curve method was used to measure concentration of the standard samples with different concentrations, and the data set was fitted linearly. It was shown that linear correlation was good at both wavelengths of 226.5 and 300 nm, and better correlation could be found at 300 nm. Therefore, high concentration xanthate solution could be measured at 226.5 nm, whereas low concentration xanthate solution could be measured at 300 nm. Afterwards, quantitative analysis of xanthate solution at different concentrations was carried out at 300 nm. The results showed that either absorbance was at maximum of 1.672 or minimum of 0.032, the linear correlation of standard curve of xanthate solution still remained good. Correlation coefficient decreased as absorbance increased continuously. It should be noted that concentration of xanthate needed to be limited less than 20 mg·L^-1 while conducting quantitative analysis. In addition, concentration of xanthate solution was measured at 300 nm under different PH of xanthate solution. It was found that at pH 3, absorbance decreased and xanthate began to decompose. When pH reached 2, absorbance became 0 and xanthate completely finished decomposition. High adsorption performance of xanthate by chalcopyrite could be explored at pH range of 5~10, and highest performance occurred at pH 9. Furthermore, adsorption capacity of xanthate by chalcopyrite surface was also measured at 300 nm. The experimental data were respectively fitted by different equation models, i. e., Freundlich and Langmuir isothermal adsorption equation model, pseudo-first-order and pseudo-second-order kinetic equation model. Sequentially, adsorption kinetics and thermodynamics of xanthate by chalcopyrite surface were studied. The results indicated that in the range of 288 to 303 K, temperature change exerted little effect on the adsorption capacity. The adsorption isotherm of xanthate by chalcopyrite surface was more consistent with Langmuir isothermal model. The actual equilibrium adsorption capacity of xanthate on chalcopyrite Q_e was less than or close to theoretical monolayer saturated adsorption capacity, and Q_m values were very close to the experimental values, indicating that adsorption of xanthate by chalcopyrite surface was dominated by monolayer chemical adsorption. With the increase of temperature, the adsorption capacity increased, meaning that temperature increment was beneficial to promote adsorption. The adsorption of xanthate on chalcopyrite was predicted to be exothermic but only small increasing extent of adsorption capacity could be observed. Thus, it would be reflected that the adsorption of xanthate on chalcopyrite is less affected by temperature. The adsorption process was spontaneous, with entropy increase and heat adsorption. The thermodynamic parameters could be calculated by Van’t Hoff equation, namely, adsorption enthalpy change Δ H=48.703 41 kJ·mol^-1, entropy change Δ S=219.403 88 J·(mol·K)^-1, and the adsorption free energy change Δ G=-16.054 93 kJ·mol^-1. Therefore, the adsorption process could be defined as chemical adsorption. Adsorption of xanthate on chalcopyrite was more consistent with pseudo-second-order kinetic equation model. Q_t value increased with temperature elevation, and the change range was very small. Consequently, it revealed that adsorption process of xanthate by chalcopyrite surface was endothermic, however, it was affected by temperature to a small extent. This was in agreement with the conclusion of thermodynamic analysis, and the value of Q_e obtained by fitting was very close to experimental value.