N，N′-二异丙氧基丙基-N″，N'''-氧二乙氧羰基硫脲在黄铜矿表面的吸附动力学和热力学特性

摘要

A novel surfactant, N, N′-dipropoxypropyl-N″, N′′-oxydiethylenedicarbonyl bis(thiourea) (DiPODECTU) was introduced, and its adsorption kinetics and thermodynamics with chalcopyrite were investigated. The results indicate that the recommended pHs for DiPODECTU adsorbing on chalcopyrite surface are 5−10 and the adsorption decreases with the increase of temperature. The isothermal adsorption model conforms to Langmuir model, and the adsorption enthalpy change and free energy change are−19.56 kJ/mol and−28.70 kJ/mol (298 K), respectively, which demonstrates that DiPODECTU adsorbes on chalcopyrite surface mainly through monolayer chemisorption. The adsorption process conforms to second-order kinetics equation and the adsorption rate constant is 0.144 m−2/(mol·h). The calculated equilibrium adsorptionQe (5.72×10−5 mol/m2) is close to the experimental valueQe (5.41×10−5 mol/m2). DiPODECTU adsorbs on chalcopyrite surface mainly through chemisorption.%研究一种新型结构的双硫脲表面活性剂—— N, N′-二异丙氧基丙基-N″, N′′-氧二乙氧羰基硫脲(DiPODECTU)在黄铜矿表面的吸附动力学和热力学。研究结果表明：黄铜矿吸附DiPODECTU较佳的pH范围为5~10，吸附量随着温度的升高而减小。等温吸附模型符合Langmuir模型，其吸附焓变ΔH为−19.56 kJ/mol，吸附自由能变ΔG为−28.70 kJ/mol(298 K)，说明DiPODECTU在黄铜矿表面为单层化学吸附。吸附过程符合二级动力学方程，吸附速率常数Ks为0.144 m−2/(mol·h)，平衡吸附量Qe为5.72×10−5 mol/m2，与实测值5.41×10−5 mol/m2接近。DiPODECTU主要以化学作用方式吸附在黄铜矿表面。