烧烤竹炭表面结构特征及其对水体中铵氮的吸附行为

Surface structure characteristics of barbecue bamboo charcoal and its adsorption behavior of ammonium from aqueous solution

在运用X射线衍射仪(XRD)、扫描电子显微镜与能谱仪(SEM-EDS)和傅立叶红外光谱议(FTIR)等仪器分析烧烤竹炭表面结构特性基础上,研究其对水体中铵氮的静态吸附行为。结果表明,以微孔为主的烧烤竹炭表面含有多种含氧官能团,如羟基、羧基等,同时还含有亚甲基、反异烯烃、芳香族和脂肪族结构;烧烤竹炭对铵氮的吸附在80 min内基本达到吸附平衡,其吸附量随着水溶液中铵氮的增加而增加,Freundlich方程能够更好地描述铵氮在烧烤竹炭上的等温吸附行为;系统的ΔG<0,ΔH>0,烧烤竹炭对铵氮的吸附作用是一个自发的吸热过程;铵氮在烧烤竹炭上的吸附动力学数据符合准二级方程,吸附过程受外部液膜扩散、表面吸附和颗粒内扩散过程的影响。

The surface structure characteristics of barbecue bamboo charcoal was analyzed using X -ray diffraction （XRD）, scanning electron microscope and X-ray energy dispersive spectrometer （SEM-EDS）, and Fourier trans-form infrared spectrometer （ FTIR） .The adsorption behavior of ammonium onto bamboo charcoal was also investiga-ted by adsorption experiments .The results showed that the barbecue bamboo charcoal was dominated with micro -pore, and contained various oxygen-functional groups （-OH,-COOH）, methylene, trans-isoolefine, aromatic and ali-phatic compounds.Ammonium adsorption equilibrium was reached within about 80 min, and the adsorption capacity of barbecue bamboo charcoal tended to increase with elevated ammonium concentration in solutions .The Freundlich isotherm equation could well describe the isothermal adsorption behavior of ammonium on barbecue bamboo charcoal . The ΔG of the equation is negative , whileΔH is positive, indicating that the adsorption reaction of ammonia nitrogen is spontaneous .The pseudo-second-order model could effectively explain the adsorption kinetics .Pore diffusion , sur-face adsorption and intra-particle diffusion would affect the adsorption process .