Chafi Safae, Cuevas-Aranda Manuel, Martínez-Cartas Mª Lourdes, Sánchez Sebastián
Department of Chemical, Environmental and Materials Engineering, Science & Technology Campus of Linares, University of Jaén, Avda. de la Universidad s/n, 23700 Linares, Spain.
Olive Grove and Olive Oils Research Institute, 23071 Jaén, Spain.
Molecules. 2025 Aug 3;30(15):3254. doi: 10.3390/molecules30153254.
In this work, biochars were produced by pyrolysis of exhausted olive pomace and evaluated as low-cost adsorbents for the removal of methylene blue (MB) from aqueous solutions. The biochar obtained at 400 °C for 1 h, which exhibited the best adsorption performance, was characterized by FTIR, N adsorption-desorption isotherms, SEM-EDX, and proximate analysis, revealing a mesoporous structure with a relatively low specific surface area but enriched in surface functional groups, likely due to the partial degradation of lignocellulosic components. Adsorption experiments were conducted to optimize operational parameters such as solid particle size (2-3 mm), agitation speed (75 rpm), and bioadsorbent dosage (1 g per 0.05 L of MB solution), which allowed for dye removal efficiencies close to 100%. Kinetic studies showed that MB adsorption followed a pseudo-second-order model, while equilibrium data at 30 °C were best described by the Langmuir isotherm ( = 0.999; = 4.25%), suggesting monolayer coverage and strong adsorbate-adsorbent affinity. Desorption trials using water, ethanol, and their mixtures resulted in low MB recovery, whereas the addition of 10% acetic acid significantly improved desorption performance. Under optimal conditions, up to 52% of the retained dye was recovered.
在本研究中，通过对废弃橄榄果渣进行热解制备生物炭，并将其作为低成本吸附剂用于去除水溶液中的亚甲基蓝（MB）。在400℃下热解1小时得到的生物炭表现出最佳吸附性能，通过傅里叶变换红外光谱（FTIR）、氮吸附-脱附等温线、扫描电子显微镜-能谱分析（SEM-EDX）和工业分析对其进行了表征，结果表明该生物炭具有介孔结构，比表面积相对较低，但表面官能团丰富，这可能是由于木质纤维素成分的部分降解所致。进行了吸附实验以优化操作参数，如固体颗粒尺寸（2-3毫米）、搅拌速度（75转/分钟）和生物吸附剂用量（每0.05升MB溶液1克），这些参数使得染料去除效率接近100%。动力学研究表明，MB吸附遵循准二级模型，而30℃下的平衡数据用朗缪尔等温线描述最佳（ = 0.999； = 4.25%），表明为单层覆盖且吸附质与吸附剂之间具有很强的亲和力。使用水、乙醇及其混合物进行的解吸试验导致MB回收率较低，而添加10%的乙酸显著提高了解吸性能。在最佳条件下，高达52%的保留染料被回收。
