Chemical oxygen demand: Historical perspectives and future challenges

Geerdink, R.B.; Hurk, Rick S. van den; Epema, Onno Jacob

doi:10.1016/j.aca.2017.01.009

Cited by 132 publications

(81 citation statements)

References 72 publications

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“…In Japan, COD Mn is used as the environmental water quality standard of organic matter in lakes, reservoirs, and coastal water [7]. The oxidation power of KMnO 4 significantly varies depending on substances [8][9][10], and hence, COD Mn covers only a limited range of organic matter and the exact components of COD Mn , which are oxidized by potassium permanganate, are unknown. This is one of the major disadvantages of this index.…”

Section: Introductionmentioning

confidence: 99%

Molecular-Level Changes in Dissolved Organic Matter Compositions in Lake Inba Water during KMnO<sub>4</sub> Oxidation: Assessment by Orbitrap Mass Spectrometry

Yuthawong

Kasuga

Kurisu

et al. 2019

J. of Wat. & Envir. Tech.

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In 2016, only 56.7% of the lakes and reservoirs in Japan complied with the standard of chemical oxygen demand determined by permanganate (COD Mn). The dissolved organic matter (DOM) contributing to COD Mn in lakes is heterogenous in nature; hence, DOM compositions in different lake waters are not well known. In this study, molecular components contributing to dissolved COD Mn (DCOD Mn) in lake water were identified via high-resolution Orbitrap mass spectrometry (Orbitrap MS). Water samples were collected from Lake Inba in September 2016. The filtered samples were oxidized by KMnO 4 according to the JIS method K0102 for different durations (ranging between 0-120 min). The DOM extracted via solid phase extraction was analyzed using Orbitrap MS, and molecular formulas were assigned. In all, 1,115 components were observed before oxidation. During time-course oxidation, components with higher unsaturation were selectively oxidized, suggesting that they contributed to the DCOD Mn in lake water. DCOD Mn components were screened for DOM in Lake Inba, and other DOM references were isolated from the Suwannee River and Lake Biwa. Only 14%-32% of the total components were regarded as DCOD Mn components, indicating the limited coverage of COD Mn. The compositions of DCOD Mn components were highly diverse, depending on the sources.

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Section: Introductionmentioning

confidence: 99%

Molecular-Level Changes in Dissolved Organic Matter Compositions in Lake Inba Water during KMnO<sub>4</sub> Oxidation: Assessment by Orbitrap Mass Spectrometry

Yuthawong

Kasuga

Kurisu

et al. 2019

J. of Wat. & Envir. Tech.

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“…This dilemma brings huge troubles to the wastewater disposal departments, local environmental monitoring and law enforcement departments as well as the water quality analysis workers. Therefore, how to eliminate the interferences of Cl − on the COD Cr determination has become a research hot for environmental monitoring workers [9].…”

Section: Introductionmentioning

confidence: 99%

A Modified Method for the Accurate Determination of Chemical Oxygen Demand (COD) in High Chloride Oilfield Wastewater

Zhang¹,

Chen²,

Liu³

et al. 2018

OJOGas

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In this work, in order to find a method for the accurate determination of chemical oxygen demand (COD Cr) in high chloride oilfield wastewater, the interferences of chloridion (Cl −) on COD Cr determination were first studied based on the Chinese national standard GB 11914-89. The results showed that the COD Cr values and deviations determined by the classical potassium dichromate (K 2 Cr 2 O 7) method increased gradually with the increase of Cl − mass concentration in water samples. Then, theoretical and experimental studies on reducing interferences of Cl − on COD Cr determination were carried out. The results showed that different concentrations of K 2 Cr 2 O 7 exhibited different oxidation capacities on Cl − , while having little effects on the oxidation of organic compounds. More specifically, when the concentration of K 2 Cr 2 O 7 was 0.025 mol•L −1 and the mass ratio of HgSO 4 :Cl − was 10:1, the interferences of Cl − on COD Cr determination were the slightest. Finally, a low concentration oxidant method was proposed for the accurate determination of COD Cr in high chloride oilfield wastewaters. The performances of the proposed method were verified by the simulated and actual high chloride oilfield wastewater. The results showed that when Cl − ≤ 20,000 mg•L −1 and COD < 100 mg•L −1 , the relative prediction errors of COD Cr provided by the proposed method were acceptable, which revealed that the low concentration oxidant method is feasible and reliable for the determination of COD Cr in high chloride oilfield wastewater.

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“…[22][23][24][25] Indeed, the two former disadvantages are satisfactorily surmounted, but the chloride still remains as a critical source of errors for that analysis. In a quantitative basis, the maximum acceptable amount of chlorides for PeCOD operation is proportional to the COD range; this information is provided by the instrument manufacturer (Table 2).…”

Section: Introductionmentioning

confidence: 99%

“…24 Because the PeCOD TM uses a flow injection (FI) process and depends on the efficiency of the photoactivation effect, the sample turbidity can cause an adverse outcome, varying the intensity according to the assay conditions; nevertheless, the limits for the presence of suspended solids are not published. The present work aims to highlight that even at acceptable concentrations of chloride and turbidity when regarding each one individually, the combined influence of both interferents can produce a synergistic effect that upsets the PeCOD TM performance.…”

Section: Introductionmentioning

confidence: 99%

The Dichromate Method versus the Photoelectrochemical Method: the Synergistic Influence of Turbidity and Chlorides on Chemical Oxygen Demand Analysis

Quintana¹,

Fagnani²,

Candello³

et al. 2017

J. Braz. Chem. Soc.

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This paper compares the dichromate method with the photoelectrochemical method (PeCOD), with regards to the influence of chloride and turbidity with chemical oxygen demand (COD) determination. Whereas the upper limits of chloride concentration are well established for both techniques, the influence of turbidity and the combined interference of underdosing chlorides and turbidity together have never been reported. When only potassium hydrogen phthalate or sorbitol were analyzed, the results show no significant difference in either method when 607 mg Cl -L -1 or 230 NTU of turbidity were added to the samples within the range of 100-900 mg L -1 COD. However, a combined effect of these two interferents leads to significantly different results, mainly for low COD range, as evidenced by the Student's t-test for paired samples (p = 0.05).

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Chemical oxygen demand: Historical perspectives and future challenges

Cited by 132 publications

References 72 publications

Molecular-Level Changes in Dissolved Organic Matter Compositions in Lake Inba Water during KMnO<sub>4</sub> Oxidation: Assessment by Orbitrap Mass Spectrometry

Molecular-Level Changes in Dissolved Organic Matter Compositions in Lake Inba Water during KMnO<sub>4</sub> Oxidation: Assessment by Orbitrap Mass Spectrometry

A Modified Method for the Accurate Determination of Chemical Oxygen Demand (COD) in High Chloride Oilfield Wastewater

The Dichromate Method versus the Photoelectrochemical Method: the Synergistic Influence of Turbidity and Chlorides on Chemical Oxygen Demand Analysis

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