Novel AOPs-Based Dual-Environmental Digestion Method for Determination of Total Dissolved Nitrogen in Water

Based on a synergistic digestion method of ultraviolet combined with ozone (UV/O3), this article investigates the reaction characteristics of nitrogen-containing compounds (N-compounds) in water and the influence of ions on digestion efficiency. In this respect, a novel and efficient AOPs-based dual-environmental digestion method for the determination of total dissolved nitrogen (TDN) in waters with complex components is proposed, in the hopes of improving the detection efficiency and accuracy of total nitrogen via online monitoring. The results show that inorganic and organic N-compounds have higher conversion rates in alkaline and acidic conditions, respectively. Meanwhile, the experimental results on the influence of Cl−, CO32−, and HCO3− on the digestion process indicate that Cl− can convert to radical reactive halogen species (RHS) in order to promote digestion efficiency, but CO32− and HCO3− cause a cyclic reaction consuming numerous •OH, weakening the digestion efficiency. Ultimately, to verify the effectiveness of this novel digestion method, total dissolved nitrogen samples containing ammonium chloride, urea, and glycine in different proportions were digested under the optimal conditions: flow rate, 0.6 L/min; reaction temperature, 40 °C; pH in acidic conditions, 2; digestion time in acidic condition, 10 min; pH in alkaline conditions, 11; digestion time in alkaline conditions, 10 min. The conversion rate (CR) of samples varied from 93.23% to 98.64%; the mean CR was greater than 95.30%. This novel and efficient digestion method represents a potential alternative for the digestion of N-compounds in the routine analysis or online monitoring of water quality.

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Investigations on Ozone-Based and UV/US-Assisted Synergistic Digestion Methods for the Determination of Total Dissolved Nitrogen in Waters

Processes ◽

10.3390/pr8040490 ◽

2020 ◽

Vol 8 (4) ◽

pp. 490 ◽

Cited By ~ 1

Author(s):

Xiaofang Sun ◽

Huixuan Chen ◽

Zhengyu Liu ◽

Mengfei Zhou ◽

Yijun Cai ◽

...

Keyword(s):

Water Sample ◽

Reaction Temperature ◽

Conversion Rate ◽

Digestion Method ◽

Dissolved Nitrogen ◽

Total Dissolved Nitrogen ◽

On Line ◽

Digestion Efficiency ◽

Uv Lamp ◽

N Compounds

Over the past two decades, the alkaline persulfate oxidation (PO) with thermal and/or ultraviolet (UV) assisted digestion method has been widely used for digestion of nitrogen containing compounds (N-compounds) in water quality routine analysis in laboratory or on-line analysis, due to its simple principle, high conversion rate, high percent recovery, low-cost. However, this digestion method still has some inevitable problems such as complex operations, high contamination potential, batch N blanks, higher reaction temperature (120–124 °C) and time-consuming (30–60 min). In this study, ozone (O3) was selected as the oxidant for digestion of N-compounds through analysis and comparison firstly. Secondly, we proposed and compared the UV and/or ultrasound (US) combined with ozone (UV/O3, US/O3 and UV/US/O3) synergistic digestion methods based on O3 with sole O3 oxidation method on digestion efficiency (digestion time and conversion rate) of standard N-compounds. Simultaneously, the influence of reaction temperature, pH of water sample, concentration of O3 and mass flow rate, UV intensity, US frequency and power on digestion efficiency were investigated, and then the optimum parameters for digestion system were obtained. Experimental results indicated that UV radiation can effectively induce and promote the decomposition and photolysis of O3 in water to generate hydroxyl radicals (•OH), while US can promote the diffusion and dissolution of O3 in water and intensify the gas-liquid mass transfer process for the reaction system. Meanwhile, results showed that the UV/US/O3 synergistic digestion method had the best digestion efficiency under the optimum conditions: water sample volume, 10 mL; pH of water sample, 11; O3 mass flow rate, 3200 mg/h; reaction temperature, 30 °C; digestion time, 25 min; UV lamp power, 18 W; distance between UV lamp and reactor, 2 cm; US frequency, 20 kHz; US power, 75 W. The conversion rate (CR) of synthetic wastewater samples varied from 99.6% to 101.4% for total dissolved nitrogen (TDN) in the range of 1.0~4.0 mg/L. The UV/US/O3 synergistic digestion method would be an effective and potential alternative for digestion of N-compounds in water quality routine analysis in laboratory or on-line analysis.

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Flow injection analysis method for determination of total dissolved nitrogen in natural waters using on-line ultraviolet digestion and vanadium chloride reduction

Microchemical Journal ◽

10.1016/j.microc.2021.105993 ◽

2021 ◽

Vol 164 ◽

pp. 105993

Author(s):

Kunning Lin ◽

Jin Xu ◽

Huige Guo ◽

Yunlong Huo ◽

Yuanbiao Zhang

Keyword(s):

Flow Injection ◽

Flow Injection Analysis ◽

Natural Waters ◽

Analysis Method ◽

Dissolved Nitrogen ◽

Total Dissolved Nitrogen ◽

On Line ◽

Vanadium Chloride

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Determination of total dissolved nitrogen in seawater based on Sequential Injection Analysis

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/461/1/012017 ◽

2020 ◽

Vol 461 ◽

pp. 012017

Author(s):

Y M Zhang ◽

Y Zou ◽

Q Shi ◽

Y Wang ◽

Z L Sun ◽

...

Keyword(s):

Sequential Injection Analysis ◽

Sequential Injection ◽

Dissolved Nitrogen ◽

Total Dissolved Nitrogen

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Simultaneous Determination of Dissolved Organic Carbon and Total Dissolved Nitrogen on a Coupled High-Temperature Combustion Total Organic Carbon-Nitrogen Chemiluminescence Detection (HTC TOC-NCD) System

Journal of Automated Methods and Management in Chemistry ◽

10.1155/jammc.2005.240 ◽

2005 ◽

Vol 2005 (4) ◽

pp. 240-246 ◽

Cited By ~ 11

Author(s):

Xi Pan ◽

Richard Sanders ◽

Alan D. Tappin ◽

Paul J. Worsfold ◽

Eric P. Achterberg

Keyword(s):

High Temperature ◽

Organic Carbon ◽

Dissolved Organic Carbon ◽

Data Acquisition ◽

Simultaneous Determination ◽

Dissolved Nitrogen ◽

Total Dissolved Nitrogen ◽

Temperature Combustion ◽

High Temperature Combustion

The marine biogeochemistries of carbon and nitrogen have come under increased scrutiny because of their close involvement in climate change and coastal eutrophication. Recent studies have shown that the high-temperature combustion (HTC) technique is suitable for routine analyses of dissolved organic matter due to its good oxidation efficiency, high sensitivity, and precision. In our laboratory, a coupled HTC TOC-NCD system with a sample changer was used for the automated and simultaneous determination of dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) in seawater samples. TOC control software was used for TOC instrument control, DOC data acquisition, and data analysis. TDN data acquisition and manipulation was undertaken under LabVIEW. The combined system allowed simultaneous determination of DOC and TDN in the same sample using a single injection and provided low detection limits and excellent linear ranges for both DOC and TDN. The risk of contamination has been remarkably reduced due to the minimal sample manipulation and automated analyses. The optimised system provided a reliable tool for the routine determination of DOC and TDN in marine waters.

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Determination of total dissolved nitrogen in natural waters1

Limnology and Oceanography ◽

10.4319/lo.1980.25.4.0751 ◽

1980 ◽

Vol 25 (4) ◽

pp. 751-754 ◽

Cited By ~ 226

Author(s):

Lucia Solórzano ◽

Jonathan H. Sharp

Keyword(s):

Dissolved Nitrogen ◽

Total Dissolved Nitrogen

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Fast method to determine the elements in maize flour: reduction in preparation time and reagent consumption

BRAZILIAN JOURNAL OF FOOD TECHNOLOGY ◽

10.1590/1981-6723.9117 ◽

2017 ◽

Vol 21 (0) ◽

Cited By ~ 1

Author(s):

Irineo Kelte Filho ◽

Mariane Butik ◽

Ana Caroline Jaski ◽

Sueli Pércio Quináia

Keyword(s):

Fast Method ◽

Maize Flour ◽

Digestion Time ◽

Preparation Time ◽

Digestion Method ◽

Sample Digestion ◽

Accuracy And Precision ◽

Reagent Consumption ◽

Validation Tests

Abstract The aim of this work was to develop and validate methodology to reduce the digestion time and reagent consumption in the determination of minerals in maize flour. The standard methodology employed in Brazil is that described by AOAC. It consists of the calcination of the sample at high temperatures for a long period of time, making the process expensive and slow. In this work, a wet sample digestion method using HNO3 was employed, heating on a block digester with final dissolution in an ultrasonic bath. The validation tests involved linearity and working range studies, and the determination of the detection and quantification limits, accuracy and precision. The sample digestion time was 1:30 h and the percent recoveries for the metals were 93% for Ca, 98% for Cu, 110% for Fe, 97% for Mg, 101% for Mn and 106% for Zn.

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A modified segmented continuous flow analysis method for simultaneous determination of total dissolved nitrogen and phosphorus in marine environments

Limnology and Oceanography Methods ◽

10.4319/lom.2014.12.577 ◽

2014 ◽

Vol 12 (8) ◽

pp. 577-591 ◽

Cited By ~ 8

Author(s):

Evgeny V. Dafner ◽

Alina M. Szmant

Keyword(s):

Simultaneous Determination ◽

Continuous Flow ◽

Flow Analysis ◽

Marine Environments ◽

Analysis Method ◽

Nitrogen And Phosphorus ◽

Dissolved Nitrogen ◽

Total Dissolved Nitrogen ◽

Continuous Flow Analysis

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Development of Optimal Digesting Conditions for Microplastic Analysis in Dried Seaweed Gracilaria fisheri

Foods ◽

10.3390/foods10092118 ◽

2021 ◽

Vol 10 (9) ◽

pp. 2118

Author(s):

Rizky Prihandari ◽

Weeraya Karnpanit ◽

Suwapat Kittibunchakul ◽

Varongsiri Kemsawasd

Keyword(s):

Raman Spectroscopy ◽

Recovery Rate ◽

Combination Method ◽

High Polymer ◽

Digestion Time ◽

Digestion Method ◽

Marine Food Web ◽

Marine Food ◽

Digestion Efficiency ◽

Digestion Methods

Currently, research on the accumulation of microplastics (MPs) in the marine food web is being highlighted. An accurate and reliable digestion method to extract and isolate MPs from complex food matrices has seldom been validated. This study aimed to compare the efficacy of MP isolation among enzymatic-, oxidative-, and the combination of two digestion methods on red seaweed, Gracilaria fisheri. The dried seaweed sample was digested using three different methods under various conditions using enzymes (cellulase and protease), 30% H2O2, and a combination of enzymes and 30% H2O2. The method possessing the best digestion efficiency and polymer recovery rate of MPs was selected, and its effect on spiked plastic polymer integrity was analyzed by Raman spectroscopy. As a result, the enzymatic method rendered moderate digestion efficiency (59.3–63.7%) and high polymer recovery rate (94.7–98.9%). The oxidative method using 30% H2O2 showed high digestion efficiency (93.0–96.3%) and high polymer recovery rate (>98%). The combination method was the most effective method in terms of digestion efficiency, polymer recovery rate, and expenditure of digestion time. The method also showed no chemical changes in the spiked plastic polymers (PE, PP, PS, PVC, and PET) after the digestion process. All the spiked plastic polymers were identifiable using Raman spectroscopy.

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