活性氮化硼的制备、表征及其对重金属离子的吸附性能
Preparation and Characterization of Actived Boron Nitride And Its Adsorption Properties for Heavy Metal Ions
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摘要: 本研究制备出一种纤维状、具有丰富孔洞的活性BN材料,其比表面积和介孔孔体积分别为944.526m2/g和0.324cm3/g。同时探究废水中Cu2 、Pb2 和Cd2 的相互作用以及活性BN的吸附行为机理,发现在单一体系中,BN吸附量遵循Pb2 >Cd2 >Cu2 ,但在三元体系中重金属离子会发生相互作用,即Cu2 对Pd2 的吸附具有协同作用,而对Cd2 的吸附具有拮抗作用,Pd2 对Cd2 的吸附在30min内具有拮抗作用,30min后具有协同作用。相反,Pd2 对Cu2 的吸附具有协同作用,而Cd2 对Cu2 的吸附具有拮抗作用,Cd2 对Pd2 的吸附具有协同作用。活性BN相较于活性炭在重金属溶液中展现较强的吸附能力,对于重金属Cu2 、Pb2 和Cd2 ,活性BN的最大吸附量分别是活性炭的1.32倍、24.75倍和20倍。针对活性BN吸附Cu2 、Pb2 和Cd2 ,发现其对Cu2 、Pb2 和Cd2 的吸附均符合Langmuir模型,说明吸附过程主要受化学吸附控制。利用XPS分析活性BN吸附后表面化学态,发现Cu2 与活性BN结合形成Cu(OH)2和-OCu,Pb2 和Cd2 与BN结合,形成PbCO3、Cd(OH)2和CdCO3。活性BN的吸附机理包括表面-NH2与重金属离子形成络合物、-OH的H与重金属离子发生离子交换、-O与重金属离子通过静电相互作用结合形成的三种吸附机制。Abstract: In this study, a fibrous activated boron nitride material with abundant pores was prepared. Its specific surface area and mesoporous pore volume were 944.526m2/g and 0.324cm3/g, respectively. At the same time, the interaction of Cu2 、Pb2 and Cd2 in wastewater and the adsorption behavior mechanism of activated boron nitride were explored. It was found that in single system, the adsorption capacity of activated boron nitride follows Pb2 >Cd2 >Cu2 , but in ternary system, heavy metal ions will interact, that is, Cu2 has a synergistic effect on the adsorption of Pb2 , and has an antagonistic effect on the adsorption of Cd2 . The adsorption of Pb2 on Cd2 has an antagonistic effect within 30 min, and has a synergistic effect after 30 min. On the contrary, Pb2 has a synergistic effect on the adsorption of Cu2 , while Cd2 has an antagonistic effect on the adsorption of Cu2 , and Cd2 has a synergistic effect on the adsorption of Pb2 . Compared with activated carbon, activated boron nitride showed stronger adsorption capacity in heavy metal solution. For heavy metals Cu2 、Pb2 and Cd2 , the maximum adsorption capacity of activated boron nitride was 1.32 times, 24.75 times and 20 times that of activated carbon, respectively. For the adsorption of Cu2 、Pb2 and Cd2 by activated boron nitride, it was found that the adsorption of Cu2 、Pb2 and Cd2 all conformed to the Langmuir model indicating that the adsorption process was mainly controlled by chemical adsorption. XPS was used to analyze the surface chemical state of activated boron nitride after adsorption. It was found that Cu2 combined with activated boron nitride to Cu(OH)2 and -OCu, Pb2 and Cd2 combine with activated boron nitride to PbCO3, Cd(OH)2 and CdCO3. The adsorption mechanism of activated boron nitride includes three adsorption mechanisms: the formation of complexes between surface-NH2 and heavy metal ions, the ion exchange between H in -OH and heavy metal ions, and the combination of B-O and heavy metal ions through electrostatic interaction.
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