热活化水化高铝水泥颗粒吸附氟化物行为研究

对水化高铝水泥颗粒(ALC)进行热活化改性,制备成活化温度t不同的吸附剂(ALCt),研究了热活化温度、pH值、共存离子和离子强度等因素对ALCt吸附氟化物性能的影响,同时利用热重分析(TGA)、X射线衍射(XRD)、傅里叶转换红外光谱(FTIR)、扫描电镜(SEM)等分析了其表面形态、内部结构特征和吸附机理.结果表明:在25℃、pH=7、初始氟浓度100mg/L条件下,热活化温度为600℃的吸附剂ALC600平衡吸附量高达17.42mg/g,且能在较宽的pH值范围(5~9)具有良好的除氟性能;共存离子Cl^-、NO3^-、SO4^2-和离子强度对ALC600的吸附效果影响不明显;ALC600的吸附过程遵循准二级动力学模型,符合Langmuir等温线模型,其理论最大吸附容量为223.72mg/g.结合吸附氟化物前后ALC600的晶体结构、化学键、表面形态的变化,确定其吸附机理是以化学吸附为主,通过内部络合和表面沉淀来实现氟离子的去除,同时也涉及离子交换和静电作用.

Behavior of Fluoride Adsorption onto Thermally DehydratedAluminate Cement Granules

Effect of activation temperature, pH value, co-existing anion and ionic strength on fluoride adsorption by the thermally dehydrated aluminate cement granules(ALC) were investigated, and TGA, XRD, FTIR, SEM were used to analyze their surface morphology, internal structure characteristics and adsorption mechanisms. The results show that the equilibrium adsorption capacity of ALC is higher than 17.42 mg/g at 25℃, the activation temperature of ALC is 600℃(ALC600), pH=7, and the initial fluoride concentration is 100 mg/L. ALC600 can efficiently remove fluoride from water in a wide pH range of 5-9. Co-existing anion(Cl^-,NO3^- and SO4^2-) and ionic strength do not evidently inhibit fluoride removing by ALC600. The adsorption processes can be fitted as pseudo-second-order model and Langmuir model, and maximum adsorption capacity is over 223.72 mg/g. According to the change of crystal structure, chemical bond and surface morphology of ALC600, the process of fluoride removed by ALC600 is mainly due to chemical adsorption, internal complexion and surface precipitation, the ion exchange and electrostatic interaction are also involved.