超声波处理对木质素磺酸钠物化性能的影响

Effect of Ultrasonic Treatment on Physicochemical Properties of Sodium Lignosulfonate

直接使用超声波处理木质素磺酸钠（ LS）水溶液,探索了超声波作用时间、功率以及体系的pH值对超声波作用效果的影响,并通过UV、FT-IR、1H NMR和TGA来考察超声波对木质素磺酸钠物化性能的影响。结果显示：超声波作用15、45、60和120 min,木质素磺酸钠的酚羟基质量分数由0.65%分别提高到0.71%、0.74%、0.81%和0.87%。10 g的LS在100 mL水中经超声波处理,超声波功率从100 W增强到300 W时,酚羟基的质量分数从0.69%提高到0.92%。超声波体系的pH值对超声波结果具有最明显的影响,当用H2 SO4调节体系的pH值为0时,超声波处理得到最高质量分数的酚羟基,高达1.58%。 UV、FT-IR和1H NMR综合结果显示,超声波对木质素磺酸钠分子的整体结构影响不大,但也会造成局部结构如苯环的部分破裂和磺酸基团的破坏。 TGA结果显示超声波对木质素磺酸钠热稳定性能的影响比较复杂,原因是超声波使降解和交联作用同时发生。300 W,20 kHz超声波处理LS水溶液60 min时,超声波的降解效应使超声波木质素磺酸钠（ ULS）在200~600℃温度区间的热稳定性低于LS；当超声波150 W 40 kHz,pH值为0（浓硫酸调节）,超声波处理60 min时处理所得的ULS,交联效应使其在680℃以上高温区的耐热性能比LS有所提高。

Sodium lignosulfonate （ LS） was treated directly by ultrasonication. The effects of ultrasonication time, power and pH on the sodium lignosulfonate were studied in present study. The physicochemical properties of sodium lignosulfonate （ LS） and sodium lignosulfonate treated with ultrasonication （ ULS） were investigated by UV, FT-IR, 1H NMR and TGA. The application of ultrasonication on sodium lignosulfonate for different time （15, 45, 60 and 120 minutes） resulted in the increment of phenolic hydroxyl to 0. 71 %, 0. 74 %, 0. 81 % and 0. 84 % from 0. 65 %, respectively. Ultrasonication was applied to 10 g sodium lignosulfonate that dissolved in 100 mL distilled water. With the ascending powder of ultrasonication from 100 to 300 W, phenolic content of sodium lignosulfonate increased from 0. 69 % to 0. 92 %. The pH exhibited the most noticeable effect on the ultrasonication. Phenolic content reached to 1. 58 % as the pH was 0. FT-IR, UV and 1H NMR showed that ultrasound might cause partial disruption of aromatic rings and sulfonic acid groups of sodium lignosulfonate. TG analysis illustrated that ultrasonication had a complex influence on thermal ability of sodium lignosulfonate due to the simultaneous degradation and cross linking reactions. When sodium lignosulfonate aqueous solution was treated by ultrasonication （300 W, 20 kHz） for 60 min, degradation had an disadvantageous effect on the thermal stability of ULS between 200 -600 ℃. However, when sodium lignosulfonate aqueous solution （pH=0,adjusted by concentrated sulfuric acid） was treated by ultrasonication （150 W, 40 kHz） for 60 min, ULS showed that the better one was over 680 ℃ because of the cross linking reactions.