摘要
采用脱硅—酸析联用技术预处理芦苇浆造纸黑液,考察了不同条件下的脱硅、酸析效果。结果表明,最佳脱硅条件为Ca(OH)2/Si O2(摩尔比)为6,65℃恒温振荡60 min。此时,黑液中Si O2质量浓度可由6.68 g/L降至0.12 g/L,脱硅率高达98.20%。最佳酸析条件为pH0.5,25℃反应30 min,然后于70℃下保温30 min,陈放8 h。此时,黑液COD可由220 141.7 mg/L降至54 000 mg/L左右,COD去除率可达75%以上。最佳脱硅—酸析预处理下,每100 mL黑液可回收8.5 g木质素。回收的木质素颗粒细小,不成纤维状,以紫丁香基单体结构和对羟基单体结构为主。
The desilication-acidification combined process was applied for pretreatment of reed pulping black liquor,and the effect of experiment conditions on treatment performance were investigated.The results showed that the optimum desilication conditions was adding certain dosage of Ca（OH）2 until the mole ration of Ca（OH）2/SiO2 was 6∶1,and reacted at 65 ℃ for 60 min,then the residual SiO2 in black liquor would decreased from 6.68 g/L to 0.12 g/L,given the SiO2 removal rate of 98.20%.Then,lignin was recovered from black liquor by acidulation-precipitation after adding sulfuric acid.The optimal acidification conditions were demonstrated as follow： pH value was 0.5,reacted at 25 ℃ for 30 min,heat preservation at 70 ℃ for 30 min and then depositing for 8 h.Under these acidification conditions,the residual COD could be reduced to about 54 000 mg/L from 220 141.7 mg/L,the COD removal rate maintained above 75%.After pretreated by desilication-acidification process,8.5 g of lignin can be got from 100 mL of black liquor.The lignin was characterized by FTIR,EDX and SEM,which showed that the main structures of lignin were syringyl monomers and hydroxyl groups and lignin particles were not fibrous but granular.
出处
《环境污染与防治》
CAS
CSCD
北大核心
2011年第6期26-31,共6页
Environmental Pollution & Control
基金
国家自然科学基金资助项目(No.50830301)
国家杰出青年科学基金资助项目(No.50925417)
国家科技支撑计划重点项目(No.2007BAC25B01)
教育部科技重大项目(No.308019)
关键词
芦苇浆造纸黑液
脱硅
酸析
木质素
reed pulping black liquor
desilication
acidulation
lignin
