羟甲基化木质素/纤维素气凝胶粒子的制备、表征及吸附性能

以羟甲基化木质素和纤维素为原料，NaOH/尿素水溶液为溶解体系，采用冷冻干燥法制备羟甲基化木质素/纤维素气凝胶粒子。采用扫描电子显微镜（SEM）、傅里叶变换红外光谱（FT-IR）仪、X射线衍射（XRD）仪、比表面积及孔径分析仪等对其结构进行了表征。研究结果表明：羟甲基化木质素分子通过氢键作用附着在纤维素骨架上，气凝胶内部仍保持三维网状结构，羟甲基化木质素的引入使得气凝胶表面出现明显收缩，网状结构的致密度随着羟甲基化木质素用量提高而逐渐降低；同时气凝胶粒子具有纤维素Ⅱ型红外吸收峰和XRD衍射峰；粒子表现出Ⅱ型吸附/脱附等温线，孔径均在15 nm以下，且随着羟甲基化木质素用量不断提高，比表面积、孔容均有所减小，HKL-4的比表面积为105.3m²/g，孔容为0.336 6cm³/g，孔径为13.67nm。吸附性能分析表明在25℃下吸附5 h，HKL-4气凝胶粒子对金胺O、亚甲基蓝和罗丹明B的吸附量分别为33.06、96.06和43.26mg/g，对亚甲基蓝的饱和吸附量可达208.7 mg/g，吸附过程更符合Langmuir等温吸附模型，主要为单分子层吸附。

Preparation,Characterization and Adsorption Performance of Hydroxymethylated Lignin/Cellulose Aerogel Particles

Hydroxymethylated lignin/cellulose composite aerogel particles were prepared by freeze-drying with NaOH/urea aqueous solution as the solution system using hydroxymethylated lignin and cellulose as raw materials. The structure of the product was characterized by scanning electron microscope(SEM), Fourier transform infrared spectroscopy(FT-IR), X-ray diffraction(XRD), specific surface area and aperture analyzer. The results showed that the methylated lignin was attached to the cellulose skeleton by hydrogen bonding, and the aerogel still maintained three-dimensional network structure. The aerogel surface shrank significantly with the introduction of methylated lignin, and the density of the network structure gradually decreased with the increase of the content of methylated lignin. At the same time, aerogel particles had cellulose Ⅱ type infrared absorption peak and XRD diffraction peak; the particles showed Ⅱ isothermal adsorption/stripping isotherm, and the apertures were all below 15 nm, and with hydroxymethyl lignin content increasing, the specific surface area, entrance reduced, and the specific surface area of HKL-4 was 105.3 m²/g, entrance was 0.336 6 cm³/g, pore size was 13.67 nm. The adsorption performance analysis showed that the unit adsorption capacities of HKL-4 aerogel particles to auramine O, methylene blue and rhodamine B at 25℃ for 5 h were 33.06, 96.06 and 43.26 mg/g, respectively, and the saturated adsorption capacity of methylene blue was up to 208.7 mg/g. The adsorption process was more consistent with the Langmuir isothermal adsorption model, mainly monolayer adsorption.