Puss Kait Kaarel, Paaver Peeter, Loog Mart, Salmar Siim
Institute of Bioengineering, Nooruse 1, Tartu, Estonia; Institute of Chemistry, University of Tartu, Ravila 14a, Tartu, Estonia.
University of Tartu, Institute of Ecology and Earth Sciences, Ravila 14a, Tartu, Estonia.
Ultrason Sonochem. 2024 Dec;111:107071. doi: 10.1016/j.ultsonch.2024.107071. Epub 2024 Sep 14.
Forest biorefineries provide multiple new avenues for applied research. The main concept lies in the malleability of the processes and their stepwise organization. The core element of the biorefinery concept addressed in the present study is the pretreatment step; here, wood biomass is converted into free hemicellulosic sugars, lignin and cellulose. In traditional approaches, the pretreatment step is a starting point for isolating and separating lignin or cellulose through different processes. In this study, instead of performing any separation, a lignin-cellulose mixture was used as its own material, and the effects of ultrasound treatment with a probe system at 20 kHz, with various amplitude, sonication time and dry matter content were investigated with the aim of assessing the formation of a nanocellulose structure with a high lignin content (>30 %) and investigating the stability of the lignin-cellulose mixture under aqueous conditions. We demonstrated the importance of dry matter content for the specific particle size and water retention values for this mixture. US treatment of lignin-cellulose mixtures <4 % dry matter formed a gel-like material, with low particle size (90 % below 30 μm and smallest at nanoscale). Low dry matter loading led to better US transfer and higher conversion of cellulose to <100 nm nanoparticles. Our study can serve as a baseline for future developments in the field of stable emulsions, filtering materials or inputs for material synthesis.
森林生物精炼厂为应用研究提供了多条新途径。其主要概念在于工艺的可延展性及其逐步组织。本研究中所探讨的生物精炼概念的核心要素是预处理步骤；在此步骤中，木质生物质被转化为游离的半纤维素糖、木质素和纤维素。在传统方法中，预处理步骤是通过不同工艺分离木质素或纤维素的起点。在本研究中，并未进行任何分离操作，而是将木质素 - 纤维素混合物作为自身材料使用，并研究了在20kHz下使用探头系统进行超声处理时，不同振幅、超声处理时间和干物质含量的影响，目的是评估高木质素含量（>30%）的纳米纤维素结构的形成，并研究木质素 - 纤维素混合物在水性条件下的稳定性。我们证明了干物质含量对于该混合物特定粒径和保水值的重要性。对干物质含量<4%的木质素 - 纤维素混合物进行超声处理形成了一种凝胶状材料，粒径较小（90%低于30μm，在纳米尺度上最小）。低干物质负载导致更好的超声传递以及纤维素向<100nm纳米颗粒的更高转化率。我们的研究可为稳定乳液、过滤材料或材料合成原料领域的未来发展提供基线。
