疏水木质纤维气凝胶的制备及其油水分离性能

Preparation of Hydrophobic Lignocellulose Aerogels for Oil-water Separation

关键词:  木质纤维  气凝胶  液相反应  疏水改性  油水分离

Key Words:lignocellulose  aerogel  liquid phase reaction  hydrophobic modification  oil-water separation

摘要:本研究以苯甲酰氯和不同碳链长度的脂肪酰氯（乙酰氯、辛酰氯和硬脂酰氯）为酯化剂、吡啶为催化剂，在二氯甲烷中对大豆茎秆气凝胶进行疏水改性，并对气凝胶的羟基取代度（DS）、多孔结构、压缩强度、水接触角（CA）、油水分离效果及循环使用性能进行探究。结果表明，疏水酯化后气凝胶的孔隙率减少，导致其吸油倍率略微降低，但压缩强度和CA显著增加。乙酰氯改性气凝胶的DS值较高（1.07），但疏水效果不佳；空间位阻和共轭效应使得苯甲酰氯改性气凝胶的DS值较低（0.58），CA仅为91°，但压缩强度显著提高，为855 kPa；辛酰氯和硬脂酰氯改性气凝胶的DS值分别为0.88和0.64，CA分别为123°和144°，具有良好的油水分离效果和循环使用性。

Abstract:In this study， the hydrophobic modification of soybean straw aerogels was carried out in methylene chloride using benzoyl chloride and fatty chlorides with different carbon chain lengths （acetyl chloride， octanoyl chloride， and stearoyl chloride） as esterifying agents， and pyridine as the catalyst. The hydroxyl substitution （DS）， porous structure， compressive strength， water contact angle （CA）， oil-water separation performance， and recycling properties of the aerogels were investigated. The results showed that the porosity of the aerogel decreased after hydrophobic esterification， resulting in a slight decrease in its oil absorption multiplicity， but the compressive strength and CA increased significantly. The DS value of acetyl chloride-modified aerogel was higher （1.07）， but the hydrophobic effect was not good. The steric effect and conjugated effect made the DS value of benzoyl chloride-modified aerogel lower （0.58）， and the CA value was only 91°， but the compressive strength was significantly increased to 855 kPa. The DS values of octanoyl chloride- and stearoyl chloride-modified aerogels were 0.88 and 0.64， respectively， and the CA values were 123° and 144°， with good oil-water separation performance and recyclability.