对硝基苯酚在高炉水淬渣上的吸附机制及表面分形研究  

Mechanism and Surface Fractal Characteristics for the Adsorption of p-nitrophenol on Water-quenched Blast Furnace Slag

作　　者：王哲[1,2] 黄国和[1] 安春江 陈莉荣[2] 张思思[2] 

机构地区：[1]华北电力大学环境研究院区域能源系统优化教育部重点实验室,北京102206 [2]内蒙古科技大学能源与环境学院,包头014010 [3]Institute for Energy,Environment and Sustainable Communities,University of Regina

出　　处：《环境科学》2016年第6期2211-2219,共9页Environmental Science

基　　金：教育部重点项目(311013)

摘　　要：研究了对硝基苯酚(p-NP)在高炉水淬渣(WBFS)上的吸附情况,用电镜扫描(SEM)、X射线衍射仪(XRD)、红外光谱仪(FTIR)、比表面积测定仪(BET)等对高炉水淬渣的理化性质进行了表征.通过批量平衡实验,从动力学和热力学角度探讨了对硝基苯酚在高炉水淬渣上的吸附作用机制.结果表明,吸附等温线能较好地用Freundlich模型来描述.ΔH和ΔS值分别为3.29 k J·mol^(-1)和4.66 J·(mol·K)^(-1),表明对硝基苯酚在高炉水淬渣上的吸附是属于吸热熵增的过程,无化学键等强作用力.ΔG值随着温度的升高而逐渐降低,说明高炉水淬渣对对硝基苯酚吸附的自发性与温度呈正比.高炉水淬渣对对硝基苯酚的吸附可分为快速的表面覆盖和慢速的内部扩散吸附2个过程,整个吸附过程符合伪二级动力学模型.运用Freundlich吸附分形模型计算了不同温度下高炉水淬渣表面的分形维数D分别为2.78、2.80、2.84以及2.87,表明高炉水淬渣的表面确实存在着分形现象,温度越高,D值越大.In the present study, the removal of p-nitrophenol （p-NP） from aqueous solution through the adsorption on water-quenched blast furnace slag （WBFS） was investigated. The physicochemical properties of the slag were characterized by SEM, XRD, FTIR and BET. Batch experiments were conducted to investigate the mechanism, kinetics and thermodynamics of adsorption process. The results showed that the experimental data could fit to Freundlich model. The enthalpy change （△H） and entropy change （△S） were 3. 29 kJ-mol - 1 and 4. 66 J·（mol-K） - 1 , respectively. It indicated that the adsorption of p-NP on WBFS was an endothermic and entropy-increasing process. The values of △G decreased with increasing temperature, indicating the spontaneous adsorption proportional to the temperature. The adsorption could be divided into two parts, one was high-speed surface coverage, and the other was slow-speed internal diffusion adsorption. It was also found that the adsorption process followed the pseudo-second-order kinetic model. The fractal dimensions of WBFS surface calculated by Freundlich adsorption fractal model were 2. 78, 2. 80, 2. 84 and 2. 87 at different temperatures, respectively. It indicated the existence of fractal phenomenon with higher fractal dimension of WBFS at higher temperature.

关 键 词：高炉水淬渣 对硝基苯酚 等温线 热力学 动力学 分形 

分 类 号：X753[环境科学与工程—环境工程]