Activated carbon monolith (ACM) was prepared from waste corrugated cardboard box (WCCB) via slurrying in seawater (SW) followed by dewatering, molding and heating under CO₂ atmosphere. The thermal process was analyzed by thermogravimetric analyzer coupled with Fourier transform infrared spectrometer (TG-FTIR). ACM was characterized by N₂-adsorption/desorption, FTIR, Raman spectroscopy and ultraviolet–visible-near infrared (UV–Vis-NIR) spectroscopy. The adsorption behavior of ACM for methylene blue (MB) and its solar steam generation performance were investigated. Results showed alkali and alkaline earth metals (AAEMs) in SW promoted the occurrence of pyrolysis of cellulose in WCCB at lower temperatures but inhibited the formation of organic volatiles, and the activation energy was reduced by 24.53 kJ mol⁻¹. AAEMs catalyzed the formation of more CO during CO₂ gasification of WCCB char between 755 and 860 °C, and the activation reaction with higher degree led to the formation of more micro- and mesopores in ACM at 785 °C. The adsorption behavior of ACM for MB fitted Langmuir model with a monolayer adsorption capacity of 174 mg g⁻¹, and ACM in floating state was also effective in adsorption of MB from water. ACM exhibited high optical absorption above 90% within a broadband wavelength, and 66.7% higher water evaporation can be achieved with the assistance of ACM during solar steam generation under the same condition.

由废瓦楞纸箱（WCCB）通过在海水（SW）中制浆，然后进行脱水，成型和在CO ₂气氛下加热来制备活性炭整料（ACM）。通过热重分析仪和傅立叶变换红外光谱仪（TG-FTIR）进行热过程分析。ACM的特征在于N ₂-吸附/解吸，FTIR，拉曼光谱和紫外可见近红外（UV-Vis-NIR）光谱。研究了ACM对亚甲基蓝（MB）的吸附行为及其太阳蒸汽产生性能。结果表明，SW中的碱金属和碱土金属（AAEMs）促进了WCCB中较低温度下纤维素热解的发生，但抑制了有机挥发物的形成，活化能降低了24.53 kJ mol ^-1。AAEMs在CO ₂期间催化了更多CO的形成WCCB炭在755至860°C之间发生气化，并且较高程度的活化反应导致在785°C下ACM中形成更多的微孔和中孔。ACM对MB拟合的Langmuir模型的吸附行为具有174 mg g ^-1的单层吸附能力，且ACM处于悬浮状态对从水中吸附MB也有效。ACM在宽带波长内显示出90％以上的高光吸收率，并且在相同条件下在太阳能蒸汽产生过程中，借助ACM可以实现66.7％的更高水分蒸发。