以固体废弃物煤矸石为主要原料,经过焙烧、酸浸和聚合等工艺制备出无机高分子絮凝剂聚合氯化铝铁(CG-PAFC)。将Al/Fe-Ferron逐时络合比色法应用于不同碱化度下CG-PAFC产品中铝铁物种形态分布测定,利用傅立叶变换红外光谱仪(FTIR)、扫描电子显微镜-能谱仪(SEM-EDS)、X射线光电子能谱仪(XPS)对CG-PAFC的分子结构和微观形貌及CG-PAFC中铁的价态进行了表征,考察了浊度、pH、投加量等因素对CG-PAFC吸附模拟水样中腐植酸的影响,并对吸附过程进行了吸附热力学、吸附动力学及吸附等温线模型拟合,探究了吸附反应的机理。结果表明:随着碱化度的增加,Al(Ⅲ),Fe(Ⅲ)的物种分布呈现相同的趋势。此外,在铝铁水解聚合过程中,Fe3+具有极强的亲OH-能力,会优先于Al3+水解,当Fe3+水解至饱和后,Al3+才开始水解聚合。FTIR分析表明CG-PAFC内部存在多种成键作用,如Al—O—Fe,Si—O—Al,Fe—OH—Al等。SEM-EDS分析显示CG-PAFC形貌呈现出致密的空间网状结构和十分发达的孔隙结构,使其具有较好的吸附性能。XPS分析表明CG-PAFC产品表面铁的化学形态呈三价。在浊度为15NTU、CG-PAFC投加量为0.2g/L、腐植酸初始质量浓度为10mg/L、温度为25℃的条件下,CG-PAFC对模拟废水中腐植酸的最大吸附量为38.47mg/g,UV254去除率达到73.68%。吸附热力学拟合结果表明腐植酸在CG-PAFC上的吸附过程为自发且无序的吸热反应。通过吸附动力学和等温线拟合结果可得出准二级动力学模型能更好地描述吸附动力学过程,颗粒内扩散拟合结果表明其吸附分多步进行。CG-PAFC对腐植酸的吸附过程符合Langmuir等温吸附模型,可见其吸附过程属于单分子层化学吸附。

In this study, coal gangue, a solid waste, was used as the main raw material to prepare inorganic polymer flocculant polymeric aluminum ferric chloride (CG-PAFC), through roasting, acid leaching, and polymerization processes. Furthermore, the distribution of Al(Ⅲ) and Fe(Ⅲ) species in CG-PAFC products at different basicity was determined by Al/Fe-Ferron timed complex colorimetric method. The molecular structure and microstructure of CG-PAFC, and the chemical form of iron on the surface of the product were characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy-energy dispersive spec- trometer (SEM-EDS) and X-ray photoelectron spectroscopy (XPS). The effect of turbidity, pH, and dosage on the adsorption of humic acid in simulated water samples by CG-PAFC were investi- gated. The adsorption process was fitted with adsorption thermodynamics, adsorption kinetics, and adsorption isotherm models to explore the mechanism of adsorption reaction. The results show that with the increasing basicity, the species distribution of Al(Ⅲ) and Fe(Ⅲ) follows the same trend. In addition, during the aluminum and iron hydrolysis polymerization process, Fe has a strong affinity for OH  , which leads to its priority over Al hydrolysis. When Fe hy- drolysis reaches saturation, Al begins hydrolysis polymerization. The FTIR analysis reveals that multiple bonding interactions, such as Al—O—Fe, Si—O—Al, Fe—OH—Al, exist in CG- PAFC. The SEM-EDS analysis shows that the morphology of CG-PAFC has a dense spatial net- work structure and a highly developed pore structure, endowing it with favorable adsorption per- formance. XPS analysis proves that the chemical form of iron on the surface of the CG-PAFC product is trivalent. Under the conditions of NTU turbidity, CG-PAFC dosage of 0.2 g/L, in- itial humic acid mass concentration of mg/L, and temperature of ℃, the maximum adsorp- tion capacity of CG-PAFC for humic acid in simulated wastewater is 38.47 mg/g, and the remov- al ratio of UV reaches 73.68%. Thermodynamic experiments with varying adsorption tempera- tures show that the adsorption process of humic acid on CG-PAFC is spontaneous and disordered endothermic. The adsorption kinetics and isotherm fitting results show that a pseudo-second-or- der model best describes the adsorption kinetics, while the intraparticle diffusion kinetics model suggests that the adsorption occurs in multiple steps. The adsorption process of HA by modified CG-PAFC is well-fitted to a Langmuir adsorption isotherm, which reveals that the adsorption process is chemical adsorption by single layer monolayer.