Abstract An alternative use for the Kraft Black liquor, the main byproduct of the pulping process, is presented in this work. It is a promising route for new biorenewable materials production, reducing dependence on petrochemicals. The synthesis of the novel biobased composites from a blend of tannin and Kraft black liquor involved a polycondensation reaction followed by a crosslinking process. This paper is the first one emphasizing the synthesis of a novel biobased composite from a blend of Kraft black liquor and tannin by performing the conventional and hydrothermal crosslinking. The hydrothermal conditions proved to be an effective strategy to obtain an oxygen-rich functional material. Besides being environmental-friendly, the hydrothermal process successfully replaced conventional curing, providing a higher yield and better chemical, functional, and structural properties. The role of two different processes, hydrothermal and pyrolysis, on the properties and adsorption performance of the final composites, was also assessed. RFA was obtained by hydrothermal conversion, processed at relatively mild conditions when compared to the pyrolysis performed to produce its carbon counterpart, RFC. Pyrolysis promoted a mesoporous structure on the RFC and the textural properties were improved. On the other hand, the severe thermal treatment degraded the RFC functional groups, increasing its basicity and decreasing the number of polar groups on the surface. RFA exhibited a smaller surface area than RFC, but it retained volatile organic matter and functional oxygen groups. These surface characteristics are known to be relevant in adsorption processes since the adsorbate-adsorbent chemical linkages and electrostatic interactions are favored. Paracetamol and aspirin adsorption onto RFA achieved the equilibrium at 480 and 720 min. On the other hand, the equilibrium for the adsorption onto RFC was achieved at 720 and 240 min. The maximum aspirin adsorption capacities onto RFA and RFC were 50.17 mg g−1 and 91.66 mg g−1, respectively. On the other hand, for paracetamol, the maximum adsorption capacities were 49.95 mg g−1 onto RFA and 73.58 mg g−1 onto RFC. The kinetic study suggested fast adsorption through a chemisorption process and the equilibrium implies the multilayer adsorption. Additionally, the major advantages of using the raw Kraft black liquor blended with tannin to synthesize the novel composites are their great availability and low cost, enabling the material large-scale production. Therefore, the results confirm the great potential of these new biomaterials as alternative adsorbents for wastewater treatment.

中文翻译：

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硫酸盐黑液和单宁混合水热合成生物基碳质复合材料及其在去除阿司匹林和扑热息痛中的应用

摘要 本文介绍了制浆过程中的主要副产品硫酸盐黑液的替代用途。这是生产新的生物可再生材料的有希望的途径，减少对石化产品的依赖。从单宁和牛皮纸黑液的混合物合成新型生物基复合材料涉及缩聚反应，然后是交联过程。本文是第一篇强调通过常规和水热交联从硫酸盐黑液和单宁的混合物合成新型生物基复合材料的论文。水热条件被证明是获得富氧功能材料的有效策略。除了环保之外，水热工艺成功地取代了传统的固化，提供了更高的产量和更好的化学、功能和结构特性。还评估了两种不同的过程，水热和热解，对最终复合材料的性质和吸附性能的作用。RFA 是通过水热转化获得的，与产生其碳对应物 RFC 的热解相比，在相对温和的条件下加工。热解促进了 RFC 上的介孔结构，并改善了质地特性。另一方面，严重的热处理使 RFC 官能团降解，增加其碱性并减少表面极性基团的数量。RFA 的表面积比 RFC 小，但它保留了挥发性有机物和功能性氧基团。已知这些表面特征与吸附过程相关，因为吸附物-吸附剂化学键和静电相互作用是有利的。扑热息痛和阿司匹林在 RFA 上的吸附在 480 和 720 分钟达到平衡。另一方面，在 720 分钟和 240 分钟时实现了 RFC 吸附的平衡。对 RFA 和 RFC 的最大阿司匹林吸附容量分别为 50.17 mg g-1 和 91.66 mg g-1。另一方面，对于扑热息痛，RFA 上的最大吸附容量为 49.95 mg g-1，RFC 上为 73.58 mg g-1。动力学研究表明通过化学吸附过程进行快速吸附，平衡意味着多层吸附。此外，使用与单宁混合的原料牛皮纸黑液合成新型复合材料的主要优点是它们的可用性高且成本低，可以实现材料的大规模生产。因此，结果证实了这些新型生物材料作为废水处理的替代吸附剂的巨大潜力。