Cholico-González Diana, Ortiz Lara Noemi, Fernández Macedo Ana María, Chavez Salas Jorge
CONACYT, Universidad Michoacana de San Nicolás de Hidalgo. Instituto de Investigación en Metalurgia y Materiales, Francisco J. Múgica S/N. Edif. "U" Ciudad Universitaria, Morelia, Michoacán 58030, Mexico.
Facultad de Ingeniería Química, Universidad Michoacana de San Nicolás de Hidalgo, Francisco J. Múgica S/N. Edif. "M" Ciudad Universitaria, Morelia, Michoacán 58030, Mexico.
ACS Omega. 2020 Feb 12;5(7):3302-3314. doi: 10.1021/acsomega.9b03385. eCollection 2020 Feb 25.
Biosorption is an alternative procedure to remove metal ions from aqueous media using agricultural waste. In this work, the adsorption capacity and removal efficiency of agave bagasse (AB) toward Pb(II), Cd(II), and Zn(II) were analyzed. Parameters such as equilibrium pH, particle size, AB dosage, time, and initial metal ion concentration were discussed. The results showed that pH 5.5, 0.4 g (<250 μm), and only 15 min of contact assured conditions for maximum adsorption capacity. The kinetic studies were fitted to the pseudo-second-order model, whereas the isotherms showed good agreement with the Langmuir model. AB has a higher affinity for Pb(II) over Cd(II) and Zn(II), and the maximum adsorption capacities were 93.14, 28.50, and 24.66 mg g, respectively. The results of the characterization evidenced two adsorption mechanisms. Scanning electron microscopy and X-ray diffraction displayed adsorption via the ion exchange mechanism by releasing Ca(II). The C cross-polarization mode with magic-angle spinning nuclear magnetic resonance analysis demonstrated a complexation mechanism by cellulose, hemicellulose, and lignin groups with Pb(II) and Cd(II), whereas the complexation is mainly observed by cellulose groups for Zn(II). AB is a good alternative for the removal of metals without prior thermal or chemical treatment, with rapid kinetics, suitable adsorption capacity, and high removal efficiency contributing to waste management.
生物吸附是一种利用农业废弃物从水介质中去除金属离子的替代方法。在这项工作中，分析了龙舌兰蔗渣（AB）对Pb(II)、Cd(II)和Zn(II)的吸附容量和去除效率。讨论了诸如平衡pH值、粒径、AB用量、时间和初始金属离子浓度等参数。结果表明，pH值为5.5、0.4 g（<250μm）且仅接触15分钟可确保达到最大吸附容量的条件。动力学研究符合准二级模型，而异等温线与朗缪尔模型吻合良好。AB对Pb(II)的亲和力高于Cd(II)和Zn(II)，最大吸附容量分别为93.14、28.50和24.66 mg/g。表征结果证明了两种吸附机制。扫描电子显微镜和X射线衍射显示通过释放Ca(II)经由离子交换机制进行吸附。具有魔角旋转核磁共振分析的C交叉极化模式表明纤维素、半纤维素和木质素基团与Pb(II)和Cd(II)发生络合机制，而对于Zn(II)，络合主要由纤维素基团观察到。AB是一种无需预先进行热处理或化学处理即可去除金属的良好替代物，具有快速的动力学、合适的吸附容量和高去除效率，有助于废物管理。
