摘要
本文首先简要介绍了木质素的来源、分类、结构和性质，其次概括了木质素基水凝胶的制备方法，然后综述了具有吸附性木质素基水凝胶和具有刺激响应性木质素基水凝胶的研究进展，最后展望了木质素基水凝胶的潜在应用。
水凝胶是一种通过交联作用形成的可以发生溶胀作用的三维多孔网络结构的高聚物。水凝胶具有柔性、生物相容性等优点，广泛应用于组织工
木质素是木质纤维的3大组分之一，是自然界含量最丰富的天然可再生芳香族聚合
木质素具有抗氧化、抗微生物、生物降解性、生物相容性等优点。因此，木质素基水凝胶是木质素高值化研究利用的一个新方向。目前，吸附性水凝胶和刺激响应性水凝胶是木质素基水凝胶的研究热点，可用于废水处理、药物缓
根据植物纤维原料的不同，木质素可以分为针叶木木质素、阔叶木木质素和禾本科木质素；根据制浆工艺的不同，木质素又可以分为硫酸盐木质素、木质素磺酸盐、有机溶剂木质素等。不同来源木质素的化学组成、结构和性质都存在明显差
木质素是由苯丙烷单元通过碳碳键和醚键连接而成的具有三维网络结构的天然大分
化学交联法是由交联剂和木质素进行化学反应制备的水凝胶。反应过程中交联剂和木质素形成了稳定的共价键，化学交联法形成过程不可逆，产物具有结构稳定的优点。化学交联木质素基水凝胶的制备方法分为直接交联聚合法和接枝交联聚合法。
木质素或改性木质素与水溶性高聚物直接交联聚合可制备木质素基水凝胶，水溶性高聚物主要包括聚氨酯、聚乙二醇二缩水甘油醚、聚乙二醇等。直接交联聚合法制备的水凝胶可通过调控木质素的含量获得良好的溶胀度、热稳定性和力学性能，并广泛应用于农业、医学等领域。Peng等
Ciolacu等
Li等
Meng等
Musilová等
接枝交联聚合法是在引发剂作用下，将单体（大多数是烯类单体）接枝至木质素上，再与交联剂进行反应制备具有功能性的木质素基水凝胶。根据单体响应性设计制备环境敏感型的刺激响应性木质素基水凝胶。Jin等
Liu等
物理交联法指木质素与交联剂通过物理作用形成的水凝胶。物理作用主要是指氢键、静电作用、范德华力等，因此物理交联木质素基水凝胶的形成过程具有可逆性。与化学交联法相比，物理交联法具有形成速度较快、环境影响小等优点，但该方法所制水凝胶稳定性较差，在特定的条件（如强酸或强碱）下，结构易被破坏。
Li等
Ravishankar等
互穿网络结构法是指将木质素以互穿或半互穿的形式引入水凝胶结构中，木质素与其他物质相互独立，具有此类结构的水凝胶网络密度较大，力学性能较强。Jesus等
Xue等
木质素的引入不仅提高了水凝胶的力学性能，而且丰富了水凝胶的特殊功能。根据木质素基水凝胶的功能，可分为吸附性木质素基水凝胶、刺激响应性木质素基水凝胶等。
木质素分子结构中的羟基、羰基和甲氧基等活性基团，不仅能与有机溶剂中的羟基形成氢键或与脂肪基形成弱相互作用（范德华力），而且能与重金属离子发生螯合（配位），因此木质素基水凝胶对有机溶剂和重金属离子等污染物具有良好的吸附（清除）作用。
Yu等
Sun等
根据外界环境变化做出刺激响应的木质素基水凝胶称为刺激响应性木质素基水凝胶，又称为智能型木质素基水凝胶。根据外界环境变化的不同，又分为温敏性、pH响应性、光敏性、磁敏性等，因此水凝胶的应用方向也不尽相同。
由于pH响应性木质素基水凝胶的溶胀度随着pH值的变化而发生变化，因此其多应用于药物控释、生物医学等领域。袁志林等
Zhu等
除单一响应性外，多重响应性是目前木质素基水凝胶的研究热点和重点，但多重响应性木质素基水凝胶还处于起步阶段，亟需进一步研究。Liu等
近几十年来，生物质资源由于可再生、生态友好性、可生物降解性等优点引起人们的关注。从前期的基础研究扩展到现在的应用领域，包括组织工程、生物医学、农业等。以可再生的木质素为原料制备水凝胶是木质素高值化利用研究的热点和难点。虽然木质素基水凝胶具有可再生、可生物降解等优点和广阔地应用前景，但仍面临着亟待解决的瓶颈问题：①进一步解构木质素的组分及结构。木质素不均一性和结构复杂性，导致其水凝胶的结构和性质存在缺陷，限制了木质素基水凝胶的应用范围。②进一步提高木质素基水凝胶的力学性能。目前，木质素基水凝胶具有一定的力学强度，但与实际应用要求仍然存在较大差距，限制了木质素基水凝胶的广泛应用。③进一步扩大木质素基水凝胶的应用。目前，木质素基水凝胶主要用于废水中重金属离子的去除、药物控释等，通过赋予新性能拓展其应用领域，如3D打印等前沿领域。
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