无汞测试高氯低有机物浓度模拟工业废水COD的原理
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摘要
从讨论Cl~-对COD的贡献出发,发现Cl~-浓度与COD的线性关系和有机物种类无关的规律,在此基础上提出一种无汞测试高氯低有机物浓度废水的COD分析方法的原理。以含氯模拟工业废水为研究对象,该原理的关键技术在于利用活性炭固定床将模拟废水中的有机物彻底分离而保留Cl~-,穿透时间是评价有机物与Cl~-分离效果的关键影响因素,并关联分析穿透时间与活性炭填充高度、进水流量和有机物初始浓度等因素的作用。结果表明,当活性炭填充高度为13.5 cm,进水流量为1.0 mL/min和有机物初始浓度为100 mg/L时,含氯模拟工业废水均可利用活性炭固定床彻底分离有机物和Cl~-;无汞COD分析方法与国家标准方法对含氯模拟工业废水的COD分析存在显著性差异,当Cl~-浓度不超过2 000 mg/L时,无汞COD分析方法的实测值在误差范围内与理论值相吻合,标准偏差处在4.11～11.34 mg/L范围内,变异系数的范围为2.19%～11.02%。综合研究认为,基于活性炭分离原理的无汞COD分析方法有望发展成为一种低污染的替代分析技术。
The contribution of Cl~- to COD was discussed and the law that the linear relationship between Cl~-concentration and COD is independent of organic species was found. A mercury-free COD analysis method for high-chlorine ion and low-organic concentration wastewater was proposed. The key step about this method is that organics are absorbed completely by activated carbon fixed bed and Cl~- is still remained in wastewater using the simulated industrial wastewater as samples. The breakthrough time is the key factor for evaluating separation effectiveness between organics and Cl~-. The influence factors of breakthrough time which are activated carbon bed height, influent flow rate and initial organic concentration was analyzed. Results indicatedthat organics are absorbed completely by activated carbon fixed bed by bed height 13.5 cm, influent flow rate1.0 mL/min and initial organic concentration 100 mg/L. There is a significant difference between the proposed mercury-free COD analysis method and national standard method. COD measured value of wastewater samples using the mercury-free COD analysis method is closed to theoretical value within error range on condition of Cl~- concentration less than 2 000 mg/L. Meanwhile, the standard deviation is in the range of4.11 mg/L to 11.34 mg/L and the coefficient of variation ranges from 2.19% to 11.02%. In summary, the mercury-free COD analysis method is expected to develop into a low-pollution alternative analysis technique.
The contribution of Cl~- to COD was discussed and the law that the linear relationship between Cl~-concentration and COD is independent of organic species was found. A mercury-free COD analysis method for high-chlorine ion and low-organic concentration wastewater was proposed. The key step about this method is that organics are absorbed completely by activated carbon fixed bed and Cl~- is still remained in wastewater using the simulated industrial wastewater as samples. The breakthrough time is the key factor for evaluating separation effectiveness between organics and Cl~-. The influence factors of breakthrough time which are activated carbon bed height, influent flow rate and initial organic concentration was analyzed. Results indicatedthat organics are absorbed completely by activated carbon fixed bed by bed height 13.5 cm, influent flow rate1.0 mL/min and initial organic concentration 100 mg/L. There is a significant difference between the proposed mercury-free COD analysis method and national standard method. COD measured value of wastewater samples using the mercury-free COD analysis method is closed to theoretical value within error range on condition of Cl~- concentration less than 2 000 mg/L. Meanwhile, the standard deviation is in the range of4.11 mg/L to 11.34 mg/L and the coefficient of variation ranges from 2.19% to 11.02%. In summary, the mercury-free COD analysis method is expected to develop into a low-pollution alternative analysis technique.
引文
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[2]韦聪,李磊,吕文英,等.工业废水CODCr测定方法与技术发展过程分析[J].中国测试, 2017, 43(7):1-9.
[3]曹臣,韦朝海,杨清玉,等.废水处理生物出水中COD构成的解析——以焦化废水为例[J].环境化学, 2012(10):1494-1501.
[4]YANGW,WANGJ,HUAM,etal.Characterization of effluent or ganicmatter from different coking waste water treatment plants[J]. Chemosphere, 2018, 203(3):68-75.
[5]ZHANGX,YEC,PIK,etal.Sustainab letreatment of desulfurization waste water byionex change and bipolar membrane electrodialysishy bridtechnology[J].Separation and PurificationTechnology,2019,211:330-339.https://www.sciencedirect.com/science/article/pii/S1383586618321634.
[6]XU H, JIA W, REN S, et al. Novel and recyclable demulsifier of expanded perlite grafted by magnetic nanoparticles for oil separation from emulsified oil wastewaters[J].Chemical Engineering Journal, 2018, 337(4):10-18.
[7]XIEY,CHENL,LIUR,etal.Reduction of AO Xin pharmaceutical waste water in the catho dechamber of bioelectrochemicalreactor[J].BioresourceTechnology,2018,265(6):437-442.
[8]GEERDINKRB,BROUWERJ,EPEMAOJ.Areliable mercury free chemicaloxygendemand(COD)method[J].ANALYTICAL METHODS, 2009, 1(2):108-114.
[9]VAIDYAB,WATSONSW,COLDIRONSJ,etal.Reduction of chlorideion interference inchemical oxygen demand(COD)determination susingbismuth-based adsorbents[J].AnalyticaChimicaActa,1997,357(1):167-175.
[10]李刘刚,吴晓芙,冀泽华,等.粟米糠-耐Pb菌株复合吸附剂固定床穿透曲线特性[J].环境科学学报, 2017, 37(7):2658-2666.
[11]龙腾,易筱筠,党志.改性花生壳对水中镉的动态吸附研究[J].环境科学, 2012, 33(9):3177-3181.
[12]RAO K S, ANAND S, VENKATESWARLU P. Modeling the kinetics of Cd(II)adsorptionon SyzygiumcuminiLleaf powder in a fixed bed mini column[J]. Journal of Industrial and Engineering Chemistry, 2011, 17(2):174-181.