陈佳琪, 曹飞, 游佳琪, 余盛禄, 卢鼎新, 孙德四, 徐建平. O—正丁基—N—异丁基硫氨酯在黄铜矿表面的吸附热力学和动力学[J]. 工程科学学报, 2023, 45(8): 1264-1271. DOI: 10.13374/j.issn2095-9389.2022.04.28.001
引用本文: 陈佳琪, 曹飞, 游佳琪, 余盛禄, 卢鼎新, 孙德四, 徐建平. O—正丁基—N—异丁基硫氨酯在黄铜矿表面的吸附热力学和动力学[J]. 工程科学学报, 2023, 45(8): 1264-1271. DOI: 10.13374/j.issn2095-9389.2022.04.28.001
CHEN Jia-qi, CAO Fei, YOU Jia-qi, YU Sheng-lu, LU Ding-xin, SUN De-si, XU Jian-ping. Adsorption thermodynamics and kinetics of O—butyl—N—isobutyl thionocarbamate on chalcopyrite surfaces[J]. Chinese Journal of Engineering, 2023, 45(8): 1264-1271. DOI: 10.13374/j.issn2095-9389.2022.04.28.001
Citation: CHEN Jia-qi, CAO Fei, YOU Jia-qi, YU Sheng-lu, LU Ding-xin, SUN De-si, XU Jian-ping. Adsorption thermodynamics and kinetics of O—butyl—N—isobutyl thionocarbamate on chalcopyrite surfaces[J]. Chinese Journal of Engineering, 2023, 45(8): 1264-1271. DOI: 10.13374/j.issn2095-9389.2022.04.28.001

O—正丁基—N—异丁基硫氨酯在黄铜矿表面的吸附热力学和动力学

Adsorption thermodynamics and kinetics of O—butyl—N—isobutyl thionocarbamate on chalcopyrite surfaces

  • 摘要: O—正丁基—N—异丁基硫氨酯(NBIB)是一种新型铜硫分离捕收剂。利用紫外−可见分光光度计进行吸附量测定,研究吸附温度、pH值、时间和捕收剂浓度等对NBIB在黄铜矿表面吸附量的影响,并进行吸附热力学和动力学研究。纯矿物浮选实验表明,NBIB对黄铜矿具有较强的捕收能力,且受pH影响很小。在温度分别为288、298、308 K,pH值为6、9、12条件下,NBIB在黄铜矿表面的吸附量随NBIB浓度的增加而增大,当平衡浓度达到0.5×10−4 mol·L−1,吸附量增加幅度变小。相同pH值时,吸附量随温度的升高而增加,推测NBIB捕收剂在黄铜矿表面的吸附为吸热过程。pH值对吸附量影响不大。将吸附量数据进行Langmuir和Freundlich方程线性拟合,NBIB在黄铜矿表面的吸附过程更符合Langmuir单分子层吸附模型。热力学计算结果表明,吸附的吉布斯自由能变(∆G)均为负值,焓变(∆H)和熵变(∆S)均为正值,说明黄铜矿吸附NBIB的过程可能为自发进行的、熵驱动的、吸热的化学吸附。吸附温度从288 K到308 K,吸附量随吸附时间和温度的增加而增大,当吸附时间达到20 min之后,吸附量的增加趋势变缓。动力学计算表明,二级反应速率方程的线性拟合结果更好,利用二级反应速率方程计算所得的平衡吸附量更接近于实验平衡吸附量,推测NBIB在黄铜矿表面的吸附符合二级吸附动力学模型。

     

    Abstract: O—butyl—N—isobutyl thionocarbamate (NBIB) is a novel collector for copper sulfur flotation separation. The adsorption capacity of NBIB was measured using a UV–vis spectrophotometer. The effects of the adsorption temperature, pH value, stirring time, and collector concentration on the adsorption capacity of NBIB on chalcopyrite surfaces, as well as its adsorption thermodynamics and kinetics, were investigated. Results of a pure mineral flotation experiment indicate that NBIB has a high recovery rate for chalcopyrite, strong collection capacity, and little influence by pH. The adsorption capacity of NBIB on a chalcopyrite surface increases with an increase in the collector concentration at 288, 298, and 308 K and pH 6, 9, and 12, respectively. When the equilibrium concentration reaches 0.5×10−4 mol·L−1, the adsorption capacity has a small increase range. At the same pH value, the adsorption capacity increases with an increase in the adsorption temperature. It is speculated that NBIB adsorption on a chalcopyrite surface is an endothermic process. At pH 6 and 9, little difference exists in adsorption capacity, which slightly decreases when pH increases to 12. Meanwhile, the pulp pH value has little effect on the adsorption capacity, which is consistent with the flotation test results. The adsorption capacity data were linearly fitted by Langmuir and Freundlich isotherms, and the Langmuir equation has a better correlation coefficient of the fitting curve. The adsorption process of NBIB on the chalcopyrite surface is more consistent with the Langmuir adsorption model, and it is speculated that the adsorption process may be monolayer adsorption. The parameters of the Langmuir equation are considered based on a thermodynamic formula. The results indicate that the linear fitting results are good, ∆G is negative, and ∆H and ∆S are positive. Therefore, the process of chalcopyrite adsorbing NBIB may be spontaneous, entropy-driven, and endothermic chemical adsorption. Meanwhile, the adsorption capacity of NBIB on the chalcopyrite surface increases with an increase in the adsorption time at temperatures from 288 K to 308 K. The increasing trend of adsorption capacity slows down after the adsorption time reaches 20 min. Moreover, the adsorption capacity increases with increasing temperature. Evidently, the adsorption is an endothermic process, which is consistent with the results of the thermodynamic analysis. The kinetic calculation shows that the correlation coefficients of the second-order reaction fitting curve are greater than those of first-order reaction, indicating that the second-order reaction rate equation has a better linear fitting result. The equilibrium adsorption capacity calculated by the second-order reaction rate equation is closer to the experimental equilibrium adsorption capacity. Therefore, it is speculated that the NBIB adsorption on the chalcopyrite surface conforms to the second-order adsorption kinetic model.

     

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