南湖新聞網訊（通訊員 李楚儀）近日，我校yl7703永利牛文娟副教授課題組和農業農村部規劃設計研究院孟海波研究員的研究成果以“Microwave–assisted hydrothermal conversion of crop straw: Enhancing the properties of liquid product and hydrochar by varying temperature and medium”為題在Energy Conversion and Management發表。該研究報道了稭稈在不同溫度和不同水熱介質條件下進行微波水熱反應，探索了稭稈微波水熱反應過程機理，并且優化了最佳反應條件。
稭稈微波水熱液體的組成成分
稭稈是天然的有機物，以木質纖維素為主，包括纖維素（40–50%）、半纖維素（15–35%）和木質素（20–30%）。木質纖維素是自然界豐富存在的天然有機物，可以通過生物精煉創造多種産品，包括生物衍生聚合物等，具有多種潛在應用價值。微波水熱技術可以實現稭稈的多組分轉化與利用，極大地回收了稭稈中的碳元素，減少了碳元素向大氣中的遷移，有利于促進我國“碳中和”目标的實現，環境效益顯著。同時，稭稈水熱固液産物具有較高的附加值，微波水熱技術有利于實現稭稈的高效轉化與高值化利用。
該研究探究了不同水熱溫度和不同介質下，稭稈微波水熱液體和水熱炭的形成機制和産物理化特性。提高水熱溫度以及添加磷酸和乙酸鎂，均提高了水熱液體的有機物和營養離子的濃度。乙酸鎂促進了稭稈水熱反應中的糖類向酸類的轉化，使水熱液體産物中的總有機化合物、總有機酸的濃度和電導率最高。
稭稈微波水熱炭活性位點與潤濕性分析
随着水熱溫度的升高，水熱炭的結晶度和孔隙結構增加，但水熱炭産率和表面活性基團減少，如C-O和N-5。乙酸鎂介質有利于水熱炭有序碳結構的生成，并能增加水熱炭表面含氮和含氧基團，同時降低水熱炭的結晶度。水熱炭的潤濕性仍然保持在較高的水平，這表明它有作為高品質多孔炭前驅體和碳基吸附材料的潛力。在乙酸鎂介質中，當水熱溫度為180 °C時，液體産物中積累的有機物最多，有機碳濃度為12662 mg/L，水熱炭擁有更多活性基團。通過水熱炭産率和液體有機碳濃度的相關文獻比較表明，乙酸鎂介質對提高水熱炭産率和水熱液體總有機碳濃度的作用顯著。水熱溫度和介質的工藝優化有利于提高稭稈微波水熱産物性能，為稭稈的微波水熱轉化技術和固液産物的增值利用提供理論基礎和技術支持，有利于實現稭稈的高效轉化與高值化利用。
水熱炭産率和液體有機碳濃度的相關文獻比較
yl7703永利2020級碩士研究生李楚儀為論文的第一作者，yl7703永利牛文娟副教授和農業農村部規劃設計研究院孟海波研究員為論文共同通訊作者，袁巧霞教授和鐘菲副教授等為參與作者，永利為第一完成單位。該研究得到了湖北省自然科學基金面上項目和農業農村部重點實驗室的支持。
審核人 袁巧霞
【英文摘要】
Crop straw is gaining increasing attention as a green resource to be converted into biofuels, chemicals, and biomaterials through microwave-assisted hydrothermal conversion (MHTC). To reduce the energy consumption and improve the product quality, this research investigated the properties and formation mechanisms of products obtained from crop straws through MHTC by varying media and temperature. Increasing temperature, phosphoric acid, and magnesium acetate could promote the liquid yield, and increase the concentrations of organic matter and nutrient ions such as K+, Ca2+,and Mg2+of liquid product. Magnesium acetate, whose liquid product exhibited the highest concentration of total organic carbon, further facilitated the conversion of sugars to acids, resulting in acidic liquid products with high electrical conductivity. Increasing temperature improved the crystallinity and pore structure of hydrochar, but reduced the hydrochar yield and surface active groups. Magnesium acetate was beneficial to generate ordered carbon structure, surface nitrogen- and oxygen-containing groups, and reduced the crystallinity of the hydrochar. The pH of liquid product in the phosphoric acid medium was the lowest, which improved the pore volume, the particle size of carbon microspheres, and the amount of carbon microspheres of hydrochar. Hydrochar exhibited good wettability and could be used as a precursor for high quality activated carbon. Compared with previous research, under the temperature of 180 °C in the magnesium acetate medium, nutrients were more preferentially accumulated in the liquid products and the hydrochar possessed more active groups. This work provides a theoretical reference and technical support for MHTC of crop straws and value-added utilization of the solid-liquid products.
論文鍊接：https://www.sciencedirect.com/science/article/pii/S0196890423005381
來源：南湖新聞網http://news.hzau.edu.cn/2023/0603/66774.shtml
