Design of eco-friendly, non-formaldehyde and flame retardant wood adhesives is in high demand for the wood industry, which can help to alleviate environmental stress and human health concerns. Magnesium oxychloride cement (MOC) can reduce CO₂ emission and increase the value-added utilization of potash industry wastes, making it an ideal alternative to hazardous formaldehyde-based adhesives. However, its practical application usually suffers from poor water resistance and the filtering effect of wood. Inspired by the porous structure of cuttlebone, a facile yet powerful strategy is presented to prepare MOC adhesive with outstanding water resistance, compressive strength and adhesive ability to wood through introducing biochar. The naturally porous structure of biochar can form a protective core-shell structure and encapsulation with hydration products to stabilize phase 5 (5Mg(OH)₂·MgCl₂·8H₂O), avoid crack extension and mitigate the filtering effect of wood. Meanwhile, the abundant functional groups of biochar can construct multiple interactions with Mg²⁺, which contributes to forming an internal network with excellent cohesion strength. Compared with pristine MOC, the obtained MOC/Biochar exhibited 102.33%, 32.33% and 31.45% increases in water resistance, compressive strength and wet adhesion strength, respectively. This work provides a promising strategy in preparing eco-friendly MOC-based adhesive from agricultural and industrial by-products to reduce environmental hazards.

木材行业对环保、无甲醛和阻燃木材粘合剂的设计有很高的需求，这有助于缓解环境压力和人类健康问题。氯氧化镁水泥（MOC）可减少CO ₂排放和增加钾肥工业废物的增值利用，使其成为有害甲醛基粘合剂的理想替代品。然而，它的实际应用通常会受到防水性和木材过滤效果差的影响。受墨鱼骨多孔结构的启发，提出了一种简便而有效的策略，通过引入生物炭制备具有出色的耐水性、抗压强度和对木材的粘合能力的 MOC 粘合剂。生物炭的天然多孔结构可形成保护性核壳结构并与水合产物包封以稳定第5相(5Mg(OH) ₂ ·MgCl ₂ ·8H ₂O)、避免裂纹扩展，减轻木材的过滤作用。同时，生物炭丰富的官能团可以与Mg ²⁺构建多重相互作用，有助于形成具有优异内聚强度的内部网络。与原始 MOC 相比，得到的 MOC/Biochar 的耐水性、抗压强度和湿粘合强度分别提高了 102.33%、32.33% 和 31.45%。这项工作为从农业和工业副产品中制备环保型 MOC 粘合剂以减少环境危害提供了一种有前景的策略。