摘要：

精制棉黑液（简称黑液）是棉短绒在加碱高温蒸煮生产精制棉过程中产生的高COD、高色度、可生化性差的黑褐色废水，对其进行有效处理是精制棉废水达标排放的关键。本研究充分利用黑液中的余热、余碱活化过硫酸盐（K₂S₂O₈）产生强氧化性的过硫酸根自由基（SO₄^·－）和羟基自由基（HO·）去除黑液中的COD和色度。结果表明：当黑液的温度为70 ℃、pH=11.0时，1 L黑液中添加50 mL 2 mmol/L的K₂S₂O₈，黑液中COD、色度、果胶的去除率达到最大，分别为94.6%、96.5%和96.3%。自由基猝灭实验结果表明，SO₄^·－和HO·对COD去除率的贡献值分别为40.6%和59.4%，说明K₂S₂O₈活化产生的HO·的氧化分解作用大于SO₄^·－。初步的研究表明，利用黑液的余热余碱活化过硫酸盐可实现黑液中COD和色度的高效、低成本去除。

关键词: 精制棉黑液, 过硫酸盐, 高级氧化, 有机污染物, 色度

Abstract:

Refined cotton black liquor（referred to as black liquor）refers to the steaming and cooking black liquor produced during the alkaline steaming and cooking process of cotton linters. Because of high COD，high chroma，and poor biodegradability，effective treatment of black liquor was key factor for refined cotton wastewater standard discharge. In present work，potassium persulfate was activated by waste heat and waste alkali in the black liquor to form sulfate radical（SO₄^·－） and hydroxyl radical（HO·），which were strong oxidant and capable of effectively removing COD and chroma. The results showed that when the condition followed temperature 70 ℃，pH 11.0，and K₂S₂O₈ dosage 50 mL with the concentration of 2 mmol/L for the 1 L black liquor，the maximum removal rates for COD，chroma and pectin from black liquor were 94.6%，96.5%，and 96.3%，respectively. Free radical quenching experiments confirmed that the role of SO₄^·－ and HO· contributed to the COD removal were 40.6% and 59.4%，respectively，which showed that the effect of pollutants removal by HO· was stronger than that of SO₄^·－ for activated potassium persulfate. This primary study results approved that using the waste heat and alkali of black liquor to activate persulfate could achieve efficient and low-cost removal of COD and chromaticity from black liquor.

Key words: refined cotton black liquor, persulfate, advanced oxidation processes, organic pollutants, chroma

中图分类号: 

• X703.1