Department of Chemistry and Environment, Universidade do Estado do Rio de Janeiro (UERJ), Resende, Brazil.
Universidade de Araraquara, Araraquara, Brazil.
J Environ Manage. 2021 Sep 1;293:112803. doi: 10.1016/j.jenvman.2021.112803. Epub 2021 Jun 2.
The reuse of açaí seeds is an organic approach for valorizing biomass, encouraging the public policies of circular economy, which reduces the human impact on the production chain processes. This research proposes an alternative for açaí seed as a filler in castor oil-based polyurethane, obtaining eco-sorbent to evaluate the sorption capacity for another impactful food industry by-product: waste cooking oil (WCO). Eco-sorbents were obtained with castor oil based-polyol and isocyanate (MDI) by mass mixing equal to 1:1 (OH:NCO), reinforced with açaí seed residue (5-20 wt%). The samples were characterized by techniques scanning electron microscopy (SEM), optical microscopy (OM), apparent density, contact angle, infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). Sorption capacity and efficiency were evaluated as a function of the fiber content, with tests performed in times of 30-180 s in two systems: oil and oil/water. The results showed that the eco-sorbents had a hydrophobic nature (θ > 98.3°) and macroporous morphology (pore size from 152 to 119 μm), which allowed the adsorption of residual cooking oil by the porous structure. The kinetics study showed that the sample with greater fiber content (15% wt.) reached the equilibrium in a short time compared to the neat PU for the oil system, with a sorption capacity of 9.50 g g in the first 30 s. For the oil/water system, an opposite behavior could be observed, with a sorption capacity of 9.98 g g in the 150 s equilibrium time. The Langmuir isotherm model presented a maximum adsorption capacity of 10.42 g g. However, the Freundlich isotherm model had a better fit to the experimental data with R (0.97) and lower chi-square (0.159), showing favorable adsorption (n = 1.496). Thus, it was proved that the weak interactions (connection H) and the binding energy of the predominant physisorption for the oil/water system. Thus, developed eco-sorbents are an excellent option for the sorption of WCO.
巴西莓籽的再利用是一种对生物质进行增值的有机方法，鼓励采用循环经济的公共政策，从而减少人类对生产链过程的影响。本研究提出了一种将巴西莓籽作为蓖麻油基聚氨酯的填料的替代方案，以获得生态吸附剂，用于评估另一种有影响力的食品工业副产物：废食用油（WCO）的吸附能力。生态吸附剂是通过质量混合等比例的蓖麻油多元醇和异氰酸酯（MDI）（OH:NCO），并加入巴西莓籽残渣（5-20wt%）制得。通过扫描电子显微镜（SEM）、光学显微镜（OM）、表观密度、接触角、红外光谱（FTIR）和热重分析（TGA）对样品进行了表征。吸附能力和效率作为纤维含量的函数进行了评估，测试在 30-180s 时间内，在两个系统：油和油水系统中进行。结果表明，生态吸附剂具有疏水性（θ>98.3°）和大孔形态（孔径为 152-119μm），这使得多孔结构能够吸附残留的食用油。动力学研究表明，与纯 PU 相比，纤维含量较大（15%wt.）的样品在油系统中达到平衡的时间较短，在 30s 内的吸附能力为 9.50gg。对于油水系统，观察到相反的行为，在 150s 的平衡时间内，吸附能力为 9.98gg。朗缪尔等温模型显示最大吸附能力为 10.42gg。然而，弗伦德利希等温模型对实验数据的拟合更好，R（0.97）和较低的卡方（0.159），显示出有利的吸附（n=1.496）。因此，证明了弱相互作用（连接 H）和主要物理吸附的结合能对油水系统的吸附有利。因此，所开发的生态吸附剂是吸附 WCO 的绝佳选择。
