da Cruz Ricardo Ribeiro, da Silva Thiago Lopes, da Silva Meuris Gurgel Carlos, Vieira Melissa Gurgel Adeodato
School of Chemical Engineering, State University of Campinas-Universidade Estadual de Campinas, Albert Einstein Av., 500, Campinas, SP, 13083-852, Brazil.
Environ Sci Pollut Res Int. 2025 Aug;32(36):21576-21595. doi: 10.1007/s11356-025-36923-1. Epub 2025 Sep 10.
Bisphenol A (BPA) is a persistent organic pollutant with toxic effects on human health and ecosystems. In this study, the performance of MWCNT-OH functionalized with iron nanoparticles (MWCNT-OH@Fe) using sugarcane bagasse extract as a reducing agent (green synthesis) was evaluated for BPA adsorption. The kinetics are fast, between 10 and 20 min in the range of concentrations evaluated and the resistance to external film diffusion (external film mass transfer) identified as the rate-limiting step of the process. The q was 0.301 mmol/g, determined by the Langmuir model, at 40 °C. The adsorption process was spontaneous and exhibited a transition in thermodynamic behavior: endothermic from 12 to 40 °C and exothermic from 40 to 55 °C. Among these methods, thermal regeneration showed the highest regeneration efficiency. The material was characterized before and after BPA adsorption using SEM/EDS, BET, FTIR, TGA, XRD, and ELS techniques. The main properties include a specific surface area of 100.3 m/g, thermal stability up to 500 °C, and a pH of 8.69. FTIR and XRD analyses confirmed iron functionalization and the presence of reduced iron species in the synthesized material. Regeneration of the adsorbent used was evaluated over three adsorption-desorption cycles using different eluent solutions, including NaCl, CaCl₂, NaOH, HNO₂, and ethanol, as well as thermal regeneration. Among these methods, thermal regeneration showed the highest efficiency, preserving the adsorption capacity of the material throughout the three adsorption/desorption cycles.
双酚A（BPA）是一种持久性有机污染物，对人类健康和生态系统具有毒性作用。在本研究中，评估了以甘蔗渣提取物作为还原剂（绿色合成法）制备的铁纳米颗粒功能化多壁碳纳米管（MWCNT-OH@Fe）对双酚A的吸附性能。吸附动力学很快，在所评估的浓度范围内10至20分钟即可完成，且外部膜扩散阻力（外部膜传质）被确定为该过程的限速步骤。根据朗缪尔模型，在40℃下测定的q为0.301 mmol/g。吸附过程是自发的，并且在热力学行为上表现出转变：在12至40℃为吸热，在40至55℃为放热。在这些方法中，热再生显示出最高的再生效率。使用扫描电子显微镜/能谱仪（SEM/EDS）、比表面积分析仪（BET）、傅里叶变换红外光谱仪（FTIR）、热重分析仪（TGA）、X射线衍射仪（XRD）和电泳光散射仪（ELS）技术对双酚A吸附前后的材料进行了表征。其主要特性包括比表面积为100.3 m/g、热稳定性高达500℃以及pH值为8.69。傅里叶变换红外光谱仪和X射线衍射仪分析证实了铁功能化以及合成材料中存在还原态铁物种。使用包括氯化钠（NaCl）、氯化钙（CaCl₂）、氢氧化钠（NaOH）、亚硝酸（HNO₂）和乙醇在内的不同洗脱液以及热再生，对所使用的吸附剂在三个吸附-解吸循环中进行了再生评估。在这些方法中，热再生显示出最高的效率，在整个三个吸附/解吸循环中均保持了材料的吸附能力。
