净水技术2025，Vol.44Issue(4)：134-140,196,8.DOI:10.15890/j.cnki.jsjs.2025.04.016
湿式氧化工艺对己内酰胺污泥处置效果与氧化液特征
Effect of Wet Oxidation Process on Caprolactam Sludge Disposal and Characteristics of Oxidation Solution
摘要
Abstract
[Objective]During the treatment of wastewater from caprolactam production,complex sludge is generated.This study investigates the detoxification and reduction efficiency of wet oxidation(WO)under various conditions,as well as the compositional changes of volatile fatty acids(VFAs)and dissolved organic matter(DOM)in the oxidation solution with increasing temperature.[Methods]The removal efficiency of detoxification and reduction was evaluated by measuring the total chemical oxygen demand(TCODCr)and volatile suspended solids(VSS)of caprolactam sludge before and after the WO process.Gas chromatography(GC)equipped with a chromatographic column and flame ionization detector(FID)was used to identify and quantify VFAs,while ultraviolet-visible absorption spectroscopy(UV-Vis)combined with three-dimensional excitation-emission matrix(3D-EEMs)and fluorescence regional integration(FRI)was employed to analyze the composition and changes of DOM at different reaction temperatures.[Results]The result showed that,compared to sludge with a moisture content of 86.8%,the TCODCr and VSS removal rates of sludge with a moisture content of 97.8%increased by 23.3%and 19.7%,respectively.Under the conditions of 97.8%moisture content,a reaction temperature of 260℃,a reaction time of 1 hour,and an initial oxygen pressure of 1 MPa,the maximum removal rates of TCODCr and VSS reached over 70%and 95%,respectively.Acetic acid accumulated with increasing reaction temperature,and the acetic acid/volatile fatty acids ratio reached a maximum of 89.6%.The 3D fluorescence spectrum-regional integral revealed two characteristic fluorescence peaks of caprolactam sludge oxidation solution located at excitation wavelength(Ex)/emission wavelength(Em)=220～235 nm/375～410 nm and Ex/Em=290～315 nm/375～405 nm.As the reaction temperature increased,the fluorescence peaks shifted to shorter emission wavelengths,and the main components of DOM were identified as tryptophan-like substances,fulvic acid-like substances,and soluble microbial metabolites.UV-Vis analysis combined with 3D fluorescence spectrum showed a decreasing trend in UV absorption coefficient at 254 nm(α254),UVt absorption coefficient at 355 nm(α355),specific ultraviolet absorbance at 254 nm(SUVA254),and humification index(HIX),while ratio of absorbance at 254 nm to absorbance at 365 nm(E2/E3)and ratio of absorbance at 300 nm to absorbance at 400 nm(E3/E4)showed an increasing trend.[Conclusion]WO demonstrates a significant treatment effect on caprolactam sludge,there is no requirement for prior dehydration.After treatment,as the temperature increases,both the concentration and molecular weight of DOM in the oxidation solution decrease,and the degree of humification and aromaticity also declines.Temperature has a pronounced effect on promoting acetic acid production,and acetic acid can serve as a potential carbon source for denitrification in subsequent wastewater treatment processes.关键词
湿式氧化(WO)/己内酰胺污泥/溶解性有机质(DOM)/紫外-可见吸收光谱(UV-Vis)/三维激发发射矩阵-荧光区域积分(3D-EEMs-FRI)Key words
wet oxidation(WO)/caprolactam sludge/dissolved organic matter(DOM)/ultraviolet-visible absorption spectroscopy(UV-Vis)/three-dimensional excitation-emission matrix integration(3D-EEMs-FRI)分类
资源环境引用本文复制引用
吴太行,李姝琪,秦树林,郑威城,刘新超..湿式氧化工艺对己内酰胺污泥处置效果与氧化液特征[J].净水技术,2025,44(4):134-140,196,8.基金项目
中国煤炭科工集团有限公司科技创新项目(2022-3-KJHZ001) （2022-3-KJHZ001）
