硝酸和硝酸铈铵协同氧化改性木质活性碳纤维

采用0.005~0.050 mol/L的硝酸铈铵,协同1.0~7.0 mol/L的硝酸,在23~83 ℃条件下,对木质活性碳纤维(WACF)浸渍5 h进行氧化改性.通过 XPS、RAMAN、水吸附和汞吸附表征其表面和结构性能.结果表明,改性后 WACF的氧/碳比平均值为0.160,酚基和醇基含量提高,羧酯含量与氧化强度总体成反比.样品表面石墨化程度降低,样品芯部的石墨化程度提高.协同改性后,WACF孔体积降低,水吸附的比表面积显著提升.WACF对汞的吸附能力和水吸附比表面积与氧原子浓度呈线性关系.硝酸可以增加官能团含量,对结构影响较小.硝酸铈铵在增加官能团含量的同时,对结构和孔径有一定调控作用,对不同直径的吸附对象有一定的选择性,拓展了 WACF的应用范围.

Synergetic Oxidation Modification of Wooden Activated Carbon Fiber with Nitric Acid and Ceric Ammonium Nitrate

The wooden activated carbon fiber(WACF)was immersed 5 h for oxidative modification,0.005 mol/L to 0.050 mol/L ammonium ceric nitrate and 1.0 mol/L to 7.0 mol/L nitric acid were added,the modification temperature was 23 ℃ to 83 ℃. The surface and structural properties were characterized by XPS,RAMAN,water vapor adsorption and mercury adsorption.The re-sults showed that the average value of oxygen/carbon ratio of modified WACF was 0.160,the content of phenolic groups and alcohol groups increased,it presented an inverse correlation between the content of carboxyeste and the intensity of oxidation.The degree of graphitization on the sample surface reduced slightly,and the degree of graphitization of the sample core increased.The pore volume decreased after synergistic modification,the specific surface area for water adsorption increased significantly.The adsorption capacity for mercury and the specific surface area for water adsorption were linearly related to the concentration of oxygen atoms.Nitric acid can increase the content of functional groups,and has little effect on the structure.While increasing the content of the functional group,ceric ammonium nitrate has a certain adjustment on the structure and pore,and definite selectivity for the adsorbed objects of diffe-rent diameters,which extends the application range of WACF.