Tancredi Nestor, Medero Natalia, Möller Fabiana, Píriz Javier, Plada Carina, Cordero Tomás
Universidad de la República, Facultad de Química, Cátedra de Fisicoquímica y Laboratorio de Fisicoquímica de Superficies, Gral. Flores 2124, CC 1157, 11800 Montevideo, Uruguay.
J Colloid Interface Sci. 2004 Nov 15;279(2):357-63. doi: 10.1016/j.jcis.2004.06.067.
Eucalyptus grandis sawdust, a major waste from the growing Uruguayan wood industry, was used in previous work to prepare powdered activated carbon (PAC). In the present work, granular activated carbon (GAC) was prepared by mixing PAC, carboxymethyl cellulose as a binder, and kaolin as reinforcer. Ultimate analysis and surface characterization of GAC and PAC were performed. Phenol adsorption was used as a way to compare the characteristics of different PAC and GAC preparations. Kinetics and isotherms of the different GAC and PAC were performed in a shaking bath at 100 rpm and 298 K. Phenol concentrations were determined by UV spectroscopy. Some kinetics parameters were calculated; from kinetics results, external resistance to mass transfer from the bulk liquid can be neglected as the controlling step. Isotherms were fitted to Langmuir and Freundlich models, and corresponding parameters were determined. Maximum phenol uptakes for all carbons were determined and correlated with carbon characteristics. Thermogravimertic analysis (TGA) determinations were performed in order to study adsorption characteristics and conditions for GAC regeneration after its use. The results showed that phenol is preferentially physisorbed on the carbon of the granules, though some chemisorption was detected. No adsorption was detected in the kaolin-carboxymethyl cellulose mixture.
巨桉木屑是乌拉圭不断发展的木材工业产生的主要废弃物，在之前的研究中被用于制备粉末活性炭（PAC）。在本研究中，通过将PAC、作为粘结剂的羧甲基纤维素和作为增强剂的高岭土混合来制备颗粒活性炭（GAC）。对GAC和PAC进行了元素分析和表面表征。采用苯酚吸附来比较不同PAC和GAC制剂的特性。在100 rpm和298 K的振荡浴中对不同的GAC和PAC进行动力学和等温线研究。通过紫外光谱法测定苯酚浓度。计算了一些动力学参数；从动力学结果来看，作为控制步骤，来自主体液体的传质外部阻力可忽略不计。将等温线拟合到朗缪尔和弗伦德里希模型，并确定了相应参数。测定了所有碳材料对苯酚的最大吸附量，并将其与碳材料特性相关联。进行了热重分析（TGA）测定，以研究GAC使用后的吸附特性和再生条件。结果表明，苯酚优先物理吸附在颗粒碳上，不过也检测到了一些化学吸附。在高岭土 - 羧甲基纤维素混合物中未检测到吸附。
