含钛渣制备多孔沸石分子筛吸附剂及其CO_(2)吸附性能

Preparation and CO2 adsorption performance of porous zeolite molecular sieve adsorbents using titanium-bearing slag

以钒钛磁铁矿高炉冶炼产生的水淬渣为主要原料,经“酸处理-碱熔-水热晶化”制备了多孔沸石分子筛吸附剂(简称吸附剂,下同),采用XRD、SEM、FTIR对吸附剂进行了表征,考察了NaAlO_(2)添加量对吸附剂结构的影响,采用动态吸附法评价了吸附剂的CO_(2)吸附性能,考察了预处理温度、吸附温度和CO_(2)流量对吸附剂的CO_(2)吸附性能的影响,并利用动力学模型进行了数据拟合,分析了其吸附行为。结果表明,随着NaAlO_(2)添加量的增加,水热晶化产物依次完成了“无定形→初步结晶→FAU型→LTA型”沸石分子筛的结构转变;制备的吸附剂(Z-4)经350℃预处理,在吸附温度25℃、CO_(2)流量分别为1.4 mL/min(固定床反应装置)和50 mL/min(同步热分析仪)的条件下,CO_(2)吸附效果最佳,其CO_(2)穿透与饱和吸附量为2.16、3.39 mmol/g;其CO_(2)吸附行为符合拟二级动力学模型,吸附过程由物理和化学吸附共同主导,拟二级动力学模型吸附速率常数为0.0785mmol/(g·s);经5次循环吸附/再生后,其CO_(2)饱和吸附量保持率为96.8%。

Porous zeolite molecular sieve adsorbents were prepared by acid treatment-alkali meltinghydrothermal crystallization using titanium-containing blast furnace slag produced during smelting process of vanadium titanium magnetite concentrate as raw material,and characterized by XRD,SEM and FTIR,with the influence of NaAlO_(2) addition on its structure analyzed.The CO_(2) adsorption performance of the adsorbents obtained were evaluated via dynamic adsorption method,while the effects of pretreatment temperature,adsorption temperature and CO_(2) flow rate on its CO_(2) adsorption performance were further investigated and the adsorption behavior was analyzed by kinetic models.The results showed that,with the increase of NaAlO_(2) addition,the hydrothermally crystallized product exhibited zeolite structure transforming from"amorphous→preliminary crystallization→FAU type→LTA type".The prepared adsorbent(Z-4)activated at 350℃exhibited the best adsorption performance at adsorption temperature of 25℃and CO_(2) flow rate of 1.4 mL/min(fixed bed reactor)or 50 mL/min(simultaneous thermal analyzer),with the CO_(2) breakthrough and saturation adsorption capacities reaching 2.16 and 3.39 mmol/g,respectively.The CO_(2) adsorption behavior conformed to the pseudo-second-order kinetic model,mainly dominated by physical and chemical adsorption,while the adsorption rate constant could reach 0.0785 mmol/(g·s).After 5 cycles of adsorption/regeneration,the retention rate of CO_(2) saturation adsorption was 96.8%.