NaHCO_(3)活化荞麦皮生物炭对碘帕醇的吸附  

Adsorption of Iopamidol by NaHCO_(3)-activated Buckwheat Biochar

作　　者：魏红[1] 赵江娟 景立明 钮金芬[3] 付冉 董雯[1] WEI Hong;ZHAO Jiang-juan;JING Li-ming;NIU Jin-fen;FU Ran;DONG Wen(State Key Laboratory of Eco-Hydraulics in Northwest Arid Region,Xi'an University of Technology,Xi'an 710048,China;School of Environmental Science and Engineering,Shaanxi University of Science&Technology,Xi'an 710021,China;Department of Applied Chemistry,Xi'an University of Technology,Xi'an 710048,China)

机构地区：[1]西安理工大学西北旱区生态水利国家重点实验室,西安710048 [2]陕西科技大学环境科学与工程学院,西安710021 [3]西安理工大学应用化学系,西安710048

出　　处：《环境科学》2023年第12期6811-6822,共12页Environmental Science

基　　金：国家自然科学基金项目(51979223);陕西省自然科学基金项目(2022JM-093,2021JM-329);陕西省重点研发计划项目(2020SF-406)。

摘　　要：采用NaHCO_(3)活化荞麦皮生物炭,优化得到生物炭0.25N-BC[m(NaHCO_(3))∶m(荞麦皮)=0.25∶1],通过SEM、BET、XRD、Raman、FTIR和XPS等方法进行表征,分析NaHCO_(3)对生物炭理化性质的影响,探究其对非离子型碘代X射线造影剂碘帕醇(IPM)的吸附性能和机制.结果表明,与荞麦皮生物炭相比(BC),NaHCO_(3)活化生物炭的结构缺陷程度更高(比表面积和孔体积分别由480.40 m^(2)·g^(-1)和0.29 cm^(3)·g^(-1)增至572.83 m^(2)·g^(-1)和0.40 cm^(3)·g^(-1),ID/IG是BC的1.22倍),表面含碳和含氧官能团数量发生显著变化,极性增强[(N+O)/C由0.15增至0.24],能够有效吸附IPM,0.25N-BC对IPM最大吸附量达到74.94 mg·g^(-1),是BC(7.88 mg·g^(-1))的9.51倍.拟二级吸附动力学和Langmuir、Freundlich等温线模型可很好地拟合0.25N-BC对IPM的吸附,吸附过程主要以化学吸附和单层、非均质多层吸附为主;孔隙填充、氢键、π—π和n—π相互作用是0.25N-BC吸附IPM的主要机制.对比不同碱[KOH、Na_(2)CO_(3)、NaHCO_(3)、KHCO_(3)和Ca(HCO_(3))_(2)]活化荞麦皮生物炭对IPM的吸附,0.25N-BC吸附效率高,达到吸附平衡时间短,能有效去除实际水体(二沉池出水和湖水)中IPM的残留,并具有良好的循环使用性能,吸附-解吸3次后对IPM的去除率仍保持在74.91%.研究表明NaHCO_(3)活化荞麦皮生物炭是一种绿色有效,可持续去除含碘有机物的优良吸附剂.NaHCO_(3)-activated buckwheat biochar was studied,and an optimal biochar of 0.25N-BC[m(NaHCO_(3)):m(buckwheat bark)=0.25:1]was selected.SEM,BET,XRD,Raman,FTIR,and XPS methods were applied to analyze the effects of NaHCO_(3) on the physicochemical properties of buckwheat biochar.The adsorption properties and mechanism of NaHCO_(3)-activated buckwheat biochar for iopamidol(IPM),a nonionic iodol X-ray contrast agent,were also investigated.The results showed that compared with buckwheat skin biochar(BC),NaHCO_(3)-activated biochar had higher structural defects(surface area and pore volume increased,respectively,from 480.40 m^(2)·g^(-1) and 0.29 cm^(3)·g^(-1) to 572.83 m^(2)·g^(-1) and 0.40 cm^(3)·g^(-1),with ID/IG being 1.22 times that of BC),the carbon and oxygen functional groups on the BC surface changed significantly,and the polarity increased[(N+O)/C from 0.15 to 0.24].The maximum adsorption capacity of 0.25N-BC for IPM was 74.94 mg·g^(-1),which was 9.51 times that of BC(7.88 mg·g^(-1)).The pseudo-second-order adsorption kinetics and Langmuir and Freundlich isotherm models could well fit the adsorption of 0.25N-BC for IPM.The adsorption processes were mainly chemical,monolayer,and heterogeneous multilayer adsorption.Pore filling,hydrogen bonding,π-π,and n-π interactions were the main mechanisms of 0.25N-BC adsorption for IPM.Comparing the activated buckwheat biochar by different bases[KOH,Na_(2)CO_(3),NaHCO_(3),KHCO_(3),and Ca(HCO_(3))2],0.25N-BC exhibited high adsorption capability and short equilibrium time and could effectively remove the IPM residue in the actual water(secondary sedimentation tank effluent and lake).The removal rate of IPM remained at 74.91% after three adsorption-desorption cycles.The results showed that NaHCO_(3)-activated buckwheat biochar was a green,effective,and sustainable adsorbent for the removal of iodine-containing organic matter.

关 键 词：荞麦皮生物炭 NaHCO_(3)活化 碘帕醇(IPM) 吸附行为 吸附机制 

分 类 号：X131.2[环境科学与工程—环境科学]