Institute of Chemistry, Federal University of Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9500, Postal Box 15003, 91501-970 Porto Alegre, RS, Brazil.
J Environ Manage. 2013 Nov 30;130:166-75. doi: 10.1016/j.jenvman.2013.09.003. Epub 2013 Sep 27.
Multi-walled carbon nanotubes (MWCNT) and powder activated carbon (PAC) were used as adsorbents for adsorption of Direct Blue 53 dye (DB-53) from aqueous solutions. The adsorbents were characterised using Raman spectroscopy, N2 adsorption/desorption isotherms, and scanning and transmission electron microscopy. The effects of initial pH, contact time and temperature on adsorption capacity of the adsorbents were investigated. At pH 2.0, optimum adsorption of the dye was achieved by both adsorbents. Equilibrium contact times of 3 and 4 h were achieved by MWCNT and PAC adsorbents, respectively. The general order kinetic model provided the best fit of the experimental data compared to pseudo-first order and pseudo-second order kinetic adsorption models. For DB-53 dye, the equilibrium data (298-323 K) were best fitted to the Sips isotherm model. The maximum sorption capacity for adsorption of the dye occurred at 323 K, with the values of 409.4 and 135.2 mg g(-1) for MWCNT and PAC, respectively. Studies of adsorption/desorption were conducted and the results showed that DB-53 loaded MWCNT could be regenerated (97.85%) using a mixture 50% acetone + 50% of 3 mol L(-1) NaOH. Simulated dye house effluents were used to evaluate the application of the adsorbents for effluent treatment (removal of 99.87% and 97.00% for MWCNT and PAC, respectively, were recorded).
多壁碳纳米管（MWCNT）和粉末状活性炭（PAC）被用作吸附剂，从水溶液中吸附直接蓝 53 染料（DB-53）。使用拉曼光谱、N2 吸附/解吸等温线、扫描和透射电子显微镜对吸附剂进行了表征。考察了初始 pH 值、接触时间和温度对吸附剂吸附容量的影响。在 pH 2.0 时，两种吸附剂对染料的吸附均达到最佳效果。MWCNT 和 PAC 吸附剂分别达到 3 和 4 h 的平衡接触时间。与拟一级和拟二级动力学吸附模型相比，一般的动力学模型为实验数据提供了最佳拟合。对于 DB-53 染料，平衡数据（298-323 K）最符合 Sips 等温线模型。在 323 K 时，染料的吸附最大吸附容量分别为 409.4 和 135.2 mg g(-1)，MWCNT 和 PAC 分别为 409.4 和 135.2 mg g(-1)。进行了吸附/解吸研究，结果表明，用 50%丙酮+50% 3 mol L(-1) NaOH 的混合物可使负载 DB-53 的 MWCNT 再生（再生率为 97.85%）。使用模拟染料厂废水评估了吸附剂在废水处理中的应用（MWCNT 和 PAC 的去除率分别为 99.87%和 97.00%）。
