Influence of porosity and surface chemistry of commercially available powdered activated carbons for the removal of dissolved organic carbon

2006 ◽  
Vol 6 (3) ◽  
pp. 27-34 ◽  
Author(s):  
R. Treguer ◽  
A. Couvert ◽  
D. Wolbert ◽  
H. Suty ◽  
G. Randon
Keyword(s):  
Drinking Water ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Surface Chemistry ◽  
Size Distribution ◽  
Activated Carbons ◽  
Size Exclusion ◽  
Drinking Water Resources ◽  
Exclusion Chromatography ◽  
Maximum Removal

More restricting legislation on Dissolved Organic Carbon (DOC) content in drinking water, especially when applied to waters with high DOC contents and low turbidity, urges the industry to improve, all along the processes, the removal of dissolved organic matter (DOM) in drinking water resources. This work focused on the characterisation of the performances of commercially available powdered activated carbons (PAC). Equilibrium isotherms were carried out on pre-treated water, i.e. after coagulation, flocculation and sedimentation. In order to determine the efficiency of the PAC, the DOM content was estimated through DOC and UV absorbance measures, as well as being characterised by size exclusion chromatography. The various experiments carried out showed some differences in the adsorption capacity, depending on their pore distribution and surface chemistry. The maximum removal ratio reached 82% and 45% for DOC and SUVA respectively. The isotherm equilibrium results can be used to define several kinds of DOC fractions, which were modelled by the Freundlich equation. Finally, the SEC chromatograms showed that the pore size distribution of the activated carbons affected significantly the compound size distribution of the removed DOM.

scholarly journals Determination of dissolved organic carbon in soils with UV spectroscopy, ultrasonic dispersion pre-treatment and separation with size exclusion chromatography .

2014 ◽  
Vol 4 ◽  
Author(s):  
Schomakers Jasmin ◽  
Mentler Axel ◽  
Herwig Mayer
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Size Exclusion Chromatography ◽  
Uv Spectroscopy ◽  
Energy Levels ◽  
Carbon Pool ◽  
Size Exclusion ◽  
Soil Types ◽  
Exclusion Chromatography ◽  
Pre Treatment

This study aimed to reveal differences in UV (ultraviolet) -absorbing dissolved organic carbon (DOC) between three prominent Austrian soil types: a Cambisol and a Chernozem developed from Tertiary marl, both under agricultural management, and a Podzol from a mixed coniferous beech forest stand. Topsoil samples (0–300 mm) were pre-treated, air-dried, sieved and four grams of each probe was added to 80 cm<sup>3</sup> of de-ionized water and subjected to ultrasonic treatment with specific energies of 6.7 J cm<sup>-3 </sup>and 161 J cm<sup>-3</sup>, respectively, which dispersed the macroaggregates and released formerly occluded soluble carbon. The soils were investigated for morphological differences with a scanning electron microscope after sonication. The suspensions were filtered &lt; 0.45 µm and UV-spectroscopy at 254 nm was performed after the dispersion pre-treatment. In addition the suspension was separated by high performance size exclusion chromatography linked to an UV-vis detector measuring at 254 nm and 210 nm and dissolved organic carbon (DOC) was determined. More DOC was released with higher specific energies for all soil types in the sequence Podzol &gt; Cambisol &gt; Chernozem but the differences in SOM/DOC ratio became less significant with increasing ultrasonic energy. The detected molecules were in the range of 1300-1600 Da for Cambisol, 1500-5400 Da for Chernozem and 1700-10400 Da for Podzol. The different energy levels reached different carbon pools. Based on a model according to von Lützow et al. (2008), the applied energy levels of 6.7 J cm<sup>-3</sup> reached the active carbon pool consisting of plant residues and exudates, and microbial/faunal biomass and residues. Sonication with 161 J cm<sup>-3</sup> dispersed more aggregate fractions and released carbon from the intermediate carbon pool where biogenic aggregation preserves the organic matter pool.

Dissolved organic carbon characteristics in an acidified groundwater-dependent ecosystem

2015 ◽  
Vol 66 (7) ◽  
pp. 582 ◽  
Author(s):  
Azra Mat Daud ◽  
Suzanne McDonald ◽  
Carolyn E. Oldham
Keyword(s):  
Molecular Structure ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Principal Component ◽  
Size Exclusion ◽  
Acidic Groundwater ◽  
Column Adsorption ◽  
Exclusion Chromatography ◽  
Doc Concentration ◽  
High Concentrations

Quantifying and characterising dissolved organic carbon (DOC) is critical to understanding its role in aquatic ecosystems. This is particularly challenging in acidic groundwater-dependent ecosystems, where low pH and high concentrations of Fe affect DOC characterisation. We investigated the variability in DOC concentrations and chemical structure in an acidic wetland, using UV visible spectrophotometry, a range of digestion methods and subsequent TOC analysis, high-pressure size exclusion chromatography (HPSEC) and rapid fractionation techniques. HPSEC results showed that increasing the pH from an original pH 2.3 to a neutral pH reduced the column adsorption of organic carbon, but did not change molecular weight distributions. Principal component analysis suggested that iron concentrations had a more direct effect on molecular structure than pH. The pH, Fe concentrations and DOC characteristics were highly dynamic and spatially variable, and were linked to surface water–groundwater connectivity, as well as horizontal connectivity of surface ponding. The changing pH and Fe concentrations affected DOC concentration and molecular structure with expected effects on bioavailability of DOC.

Minimization of the Disinfection by-Product Precursors in Treated Waters Exposed to Ozone and Chlorine

2014 ◽  
Vol 884-885 ◽  
pp. 91-95
Author(s):  
Shang Chao Yue ◽  
Le Jun Zhao ◽  
Xiu Duo Wang ◽  
Qi Shan Wang ◽  
Feng Hua He
Keyword(s):  
Drinking Water ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Water Supply ◽  
River Water ◽  
Water Samples ◽  
Full Scale ◽  
Ultraviolet Absorbance ◽  
Treatment Processes ◽  
Removal Efficiencies

The objectives of this study were to investigate impact of preoxidation on disinfection by-product (DBP) precursors in drinking water via two different preoxidation methods. The full-scale study was conducted on surface river water in a water supply plant in Tianjin, China. Two treatment trains were performed, with prechlorination and preozonation as preoxidation methods, respectively. The water samples were collected on different stages along the treatment processes and analyzed by following organic parameters: dissolved organic carbon (DOC), UV254 and specific ultraviolet absorbance (SUVA). The results indicated that Train 2 with preozonation was more effective to reduce DBP precursors. Preozonation possessed an excellent ability in the removal of UV254 and SUVA, the removal efficiencies were 25.14% and 18.77%, respectively, comparing to the removal rates of 6.66% and 5.64% during prechlorination, separately.

Practical application of a combined treatment process for removal of recalcitrant NOM - alum and PAC

2004 ◽  
Vol 4 (4) ◽  
pp. 89-94 ◽  
Author(s):  
R. Fabris ◽  
C.W.K. Chow ◽  
M. Drikas
Keyword(s):  
High Performance ◽  
Treatment Process ◽  
Activated Carbons ◽  
Combined Treatment ◽  
Size Exclusion ◽  
Practical Application ◽  
Aluminium Sulphate ◽  
Treated Water ◽  
Trihalomethane Formation Potential ◽  
Exclusion Chromatography

Three different powdered activated carbons were applied in combination with aluminium sulphate to treat a high dissolved organic carbon (DOC) source water with a focus on improving natural organic matter removal. Treated water quality was analysed using absorbance at 254 nm, DOC, trihalomethane formation potential (THM-FP), rapid fractionation, C13 NMR and molecular weight distribution by high performance size exclusion chromatography. Carbon C and B offered equivalent DOC removal but carbon C was considered superior as treated water THM-FP was reduced. It is postulated that an organic fraction around 1000 Daltons is responsible for differences in THM-FP shown in the treated waters.

scholarly journals Small-scale drinking water treatment unit of filtration and UV disinfection for remote area

2020 ◽  
Vol 20 (6) ◽  
pp. 2106-2118
Author(s):  
Kassim Chabi ◽  
Jie Zeng ◽  
Lizheng Guo ◽  
Xi Li ◽  
Chengsong Ye ◽  
...  
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Water Treatment ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Bacterial Community Composition ◽  
Drinking Water Treatment ◽  
Small Scale ◽  
Treatment Unit ◽  
Remote Areas

Abstract People in remote areas are still drinking surface water that may contain certain pollutants including harmful microorganisms and chemical compounds directly without any pretreatment. In this study, we have designed and operated a pilot-scale drinking water treatment unit as part of our aim to find an economic and easily operable technology for providing drinking water to people in those areas. Our small-scale treatment unit contains filtration and disinfection (UV–C irradiation) stages to remove pollutants from source water. The water quality index was determined based on various parameters such as pH, temperature, dissolved oxygen, nitrate, nitrite, ammonium, phosphorus, dissolved organic carbon and bacteria. Water and media samples after DNA extraction were sequenced using Illumina MiSeq throughput sequencing for the determination of bacterial community composition. After the raw water treatment, the reduction of bacteria concentration ranged from 1 to 2 log10. The average removal of the turbidity, ammonium, nitrite, phosphorus and dissolved organic carbon reached up to 95.33%, 85.71%, 100%, 28.57%, and 45%, respectively. In conclusion, multiple biological stages in our designed unit showed an improvement of the drinking water quality. The designed drinking treatment unit produces potable water meeting standards at a lower cost of operation and it can be used in remote areas.

scholarly journals Effects of ortho- and polyphosphates on lead speciation in drinking water

2018 ◽  
Vol 4 (4) ◽  
pp. 505-512 ◽  
Author(s):  
Benjamin F. Trueman ◽  
Wendy H. Krkošek ◽  
Graham A. Gagnon
Keyword(s):  
Drinking Water ◽  
Size Exclusion Chromatography ◽  
Size Exclusion ◽  
Lead Speciation ◽  
Exclusion Chromatography

Polyphosphates may increase lead solubilityviacomplexation, but the risk is not well characterized. Size-exclusion chromatography with multi-element detection could help determine the prevalence of lead-polyphosphate complexes in drinking water.

scholarly journals Concentration of Total Organic Carbon and Its Fractions in Surface Water in Poland and Germany

Proceedings ◽  
2020 ◽  
Vol 51 (1) ◽  
pp. 35
Author(s):  
Patrycja Sobczak ◽  
Agata Rosińska
Keyword(s):  
Drinking Water ◽  
Surface Water ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Total Organic Carbon ◽  
Rhine River ◽  
Bacteriological Quality ◽  
Quality Of Water ◽  
Biodegradable Dissolved Organic Carbon

Total organic carbon (TOC) present in surface water consists of different fractions like dissolved organic carbon (DOC) or biodegradable dissolved organic carbon (BDOC). BDOC may have an impact on the bacteriological quality of water as it can be a source of carbon and energy for microorganisms. It is important to consider this parameter in case of the distribution of drinking water. The aim of this research was to compare the qualities of chosen surface water in Poland and Germany in terms of concentration of total organic carbon and its fractions. The samples were taken from the reservoir in Poland and Rhine River in Germany. The first one is a source of drinking water for humans. The research showed that, considering the analyzed compounds, the water from the river has better quality.

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