介孔碳及其铁改性材料吸附水中对硝基苯酚

Adsorption of p-Nitrophenol From Aqueous Solution by Mesoporous Carbon and Its Fe-Modified Materials

采用水热合成法以F127为模板剂制备介孔碳材料(MC),一步合成法引入Fe(NO_3)_3·9H_2O得到铁改性介孔碳材料(Fe/MC-x,x为合成原料中铁源与间苯二酚的摩尔比,x=0.5、1.0、1.5),对改性前后的材料进行TEM、N_2吸-脱附、XRD及FI-TR表征,通过考察吸附剂量、吸附等温线、吸附动力学对其吸附水中对硝基苯酚(p-NP)进行了研究。结果表明,所得MC和Fe/MC-x的孔径分布集中于3～4nm,比表面积分别为643.6、635.6、636.0和587.2 m^2/g。实验条件下,Fe/MC-x的吸附性能优于MC,其中Fe/MC-1.0有最大吸附量220.35mg/g,对应去除率为92.33%;平衡吸附量均与初始浓度呈正相关,与吸附剂投加量呈负相关,高温不利于吸附,p-NP在MC和Fe/MC-x上的吸附行为符合Freundlich模型;改性行为加快了吸附速率,吸附过程符合准二级动力学模型,主要为化学吸附控制吸附速率。

Mesoporous carbon (MC)was prepared in the approach of hydrothermal synthesis, with F127 as template.Iron(Ⅲ) nitrate nonahydrate Fe(NO3)3·9H2O was added into the synthesis system to prepare Fe-modified mesoporous carbon(Fe/MC-x, x is the molar ratio of Fe to resorcinol, x=0.5, 1.0, 1.5)by one-step method.TEM, N2 adsorption-desorption, XRD and FT-IR were used to characterize the textural properties of MC and Fe/MCx(x=0.5, 1.0, 1.5)).The adsorption behavior of p-nitrophenol (p-NP) by these materials in aqueous solution was investigated, including the dosage of the adsorbent, adsorption isotherm and adsorption kinetics.Results show that the pore sizes of MC and Fe/MC-x are around 3-4 nm, and the BET specific surface areas are 643.6 m^2/g (for MC) and 635.6 m^2/g (for Fe/MC-0.5), 636.0 m^2/g (for Fe/MC-1.0) and 587.2 m^2/g (for Fe/MC-1.5), respectively.The adsorption performance of Fe/MC-x is better than MC and Fe/MC-1.0 has the highest adsorption capacity of 220.35 mg/g under the experimental conditions, and the corresponding removal rate is 92.33%.For these two kinds of materials, the equilibrium adsorption capacities are positively related to the initial concentration, and negatively related to the dosage of the adsorbent.High temperature is unfavorable for adsorption.p-NP adsorption by MC and Fe/MC-x fits well with the Freundlich adsorption isotherms, the adsorption rates are accelerated by the modification.The adsoption processes are described well using pseudo-second-order kinetics, and the main control processes of adsorption rates are chemical adsoption.