摘要
目的粉煤灰(FA)具有多孔结构和较大的比表面积,且富含铁铝氧化物使其对重金属具有一定的吸附效果。但对重金属的去除能力仍然有限,为了提高对重金属的吸附移除效率对FA进行了负磁改性。方法为进一步提高粉煤灰对重金属的吸附能力,采用共沉淀法制备了磁性粉煤灰(MFA)。通过批量实验和SEM、XRD、FTIR和XPS等方法考察其对铅(Pb)和铜(Cu)的吸附效果。结果SEM分析表明负磁改性破坏了FA的玻璃微球结构,MFA的比表面积较FA增加了13.4倍;XRD和XPS分析表明MFA中新增了Fe_(3)O_(4)和Fe_(2)O_(3)特征峰,显著增加了Fe_(3)O_(4)的含量,表明成功对MFA进行了负磁改性。FA和MFA对Pb和Cu的等温吸附过程符合Langmuir模型,且MFA对Pb和Cu的最大吸附量达到28.1和90.1mg/g,较FA分别提高了35.6%和69.9%。解吸实验显示MFA和FA吸附Pb后基本不解吸,且MFA对Cu的解吸率显著低于FA。拟二阶动力学模型可以较好地拟合FA和MFA对Pb和Cu的吸附动力学过程,R^(2)达到0.961~0.999。随着溶液pH的增加,FA和MFA对Pb和Cu吸附逐渐增加,且MFA对Pb和Cu吸附能力是FA的1.22~6.17倍。结论本研究表明负磁改性显著增加了MFA对Pb和Cu的吸附固定能力,在Pb和Cu污染废水的吸附移除方面具有较好的应用潜力,为粉煤灰的资源化利用提供了新的方法。
Objective Fly ash(FA)is characteristic of porous structure and large specific surface area and rich in iron and aluminum oxides,therefore with a certain but limited capacity to adsorb heavy metals.In order to enhance the absorption efficiency,the FA was magneticly modified.Methods The magnetic fly ash(MFA)was prepared by the co-precipitation method.The effect of the adsorption to Pb and Cu was investigated through the batch experiments,SEM,XRD and FTIR,and XPS.Results SEM analysis showed that the magnetic modification destroyed the glass microsphere structure of FA,and enhanced the specific surface area of MFA by 13.4 times than that of FA.XRD and XPS analysis showed that the characteristic peaks of Fe_(3)O_(4) and Fe_(2)O_(3) appeared in MFA,meaning the significant increase of the Fe_(3)O_(4) content,which verified the success of the magnetic modification of MFA.The isothermal adsorption process of Pb and Cu by FA and MFA was well fitted with the Langmuir model,and the maximum adsorption capacities of Pb and Cu by MFA reached 28.1mg/g and 90.1mg/g,35.6%and 69.9%higher than that of FA respectively.The desorption experiment showed that there was little desorption phenomenon after Pb was adsorbed by MFA and FA,and the desorption rate of Cu by MFA was significantly lower than that by FA.The pseudo-second-order kinetic model fit the adsorption kinetic process of Pb and Cu by FA and MFA well,with R^(2)reaching 0.961~0.999.With the increase of solution pH,the adsorption of Pb and Cu by FA and MFA gradually increased,and the adsorption capacity of Pb and Cu by MFA was 1.22~6.17 times higher than that of FA.Conclusion The magnetic modification increases significantly the adsorption and fixation capacity of MFA for Pb and Cu and have great application potential in the adsorption and removal of Pb and Cu polluted wastewater,providing a new method for the resource utilization of fly ash.
作者
崔红标
郭腾飞
徐志
张世文
张晨光
CUI Hongbiao;GUO Tengfei;XU Zhi;ZHANG Shiwen;ZHANG Chenguang(School of Earth and Environment,Anhui University of Science and Technology,Huainan Anhui 232001,China;Wuhan ourheroes Technology Co.LTD,Wuhan Hubei 430020,China)
出处
《安徽理工大学学报(自然科学版)》
2024年第6期25-34,共10页
Journal of Anhui University of Science and Technology:Natural Science
基金
采煤地表沉陷区水面种植关键技术及模式研究与示范(HX2024012395)。
关键词
粉煤灰
磁性
吸附
fly ash
magnetic
adsorption
作者简介
崔红标(1985-),男,安徽凤台人,教授,博士,研究方向:土壤重金属污染修复。
