硼掺杂介孔炭吸附四环素的效能与机制

Efficacy and Mechanism of Tetracycline Adsorption by Boron-doped Mesoporous Carbon

以椰壳和硼酸为原料,通过简单的一步热解法制备出新型硼掺杂椰壳介孔炭材料(B-CSC)用于水中四环素类污染物的高效吸附去除.系统研究了关键制备条件热解温度和硼碳质量比对其吸附性能的影响,使用比表面积及孔径分析仪(BET)、场发射扫描电镜(SEM)、X射线光子能谱仪(XPS)、拉曼光谱仪(Raman)以及Zeta电位仪(Zeta)对其微观结构及物化性质进行了表征分析.系统考察了初始pH值、不同金属阳离子以及不同背景水质条件对其吸附效果的影响.结合材料表征与相关分析等对其强化吸附机制进行了深入讨论与分析.结果表明,一步热解能够将硼掺入椰壳炭的表面及晶格,导致其拥有更大的比表面积和孔体积,引入硼的形态主要是H_(3)BO_(3)、B_(2)O_(3)、B和B_(4)C.B-CSC对四环素的吸附量达到297.65 mg·g^(-1),是原始椰壳介孔炭(CSC)的8.9倍.同时,B-CSC对于水环境中常见污染物罗丹明B(RhB)、双酚A(BPA)和亚甲基蓝(MB)的吸附量分别高达372.65、255.24和147.82 mg·g^(-1).B-CSC对四环素的吸附过程是物理化学作用共同主导的,主要涉及液膜扩散、表面吸附、介孔与微孔内扩散和活性位点吸附,H3BO3是其主要吸附位点.吸附强化机制主要是硼掺杂降低了其碳网络的化学惰性,增强了其与四环素分子的π—π相互作用和氢键作用.

Using coconut shell and boric acid as raw materials,a new boron-doped coconut shell mesoporous carbon material(B-CSC)was prepared using a simple one-step pyrolysis method for efficient adsorption and removal of tetracycline pollutants in water.The effects of pyrolysis temperature and boron-carbon mass ratio on the adsorption performance under key preparation conditions were systematically studied,and their microstructure and physicochemical properties were characterized using a specific surface area and pore size analyzer(BET),field emission scanning electron microscopy(SEM),X-ray photon spectroscopy(XPS),Raman spectrometer(Raman),and Zeta potentiometer(Zeta).The effects of initial pH,different metal cations,and different background water quality conditions on the adsorption effect were systematically investigated.Combined with material characterization and correlation analysis,the enhanced adsorption mechanism was discussed and analyzed in depth.The results showed that one-step pyrolysis could incorporate boron into the surface and crystal lattice of coconut shell charcoal,resulting in a larger specific surface area and pore volume,and the main forms of boron introduced were H_(3)BO_(3),B_(2)O_(3),B,and B4C.The adsorption capacity of B-CSC to tetracycline reached 297.65 mg·g^(-1),which was 8.9 times that of the original coconut shell mesoporous carbon(CSC).At the same time,the adsorption capacity of B-CSC for rhodamine B(RhB),bisphenol A(BPA),and methylene blue(MB),common pollutants in aquatic environments,was as high as 372.65,255.24,and 147.82 mg·g^(-1),respectively.The adsorption process of B-CSC to tetracycline was dominated by physicochemical interaction,mainly involving liquid film diffusion,surface adsorption,mesoporous and microporous diffusion,and active site adsorption,and H3BO3 was the main adsorption site.The adsorption strengthening mechanism mainly reduced the chemical inertness of the carbon network and enhanced its π—π interaction and hydrogen bonding with tetracycline molecules.