Junias Adusei-Gyamfi. Supervisors: University of Lille: Justine Criquet, Baghdad Ouddane TU Delft: Bas Heijman, Luuk Rietveld. Second DOC2C's workshop

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1 Characterization of Natural Organic Matter and processes during drinking water treatments Junias Adusei-Gyamfi 1 Supervisors: University of Lille: Justine Criquet, Baghdad Ouddane TU Delft: Bas Heijman, Luuk Rietveld Second DOC2C's workshop

2 Summary 2 Introduction Problem context Methodology Results Conclusions and Perspectives

3 Introduction 3 Natural organic matter (NOM) refers to a complex mixture of different organic compounds that are present in fresh water Increase in quantity and a change in quality Threat to drinking water treatment processes Source Great influence on its properties

4 Problem Context 4 Effects of NOM in water; Aesthetic effects (colour, taste and odour) Biological growth in distributing network channels Complexation with other pollutants present e.g. trace metals Increase in the dosage of treatment chemicals Production of disinfection by-products (DPB) Competition with target pollutants

5 5 Characterization Parameters Parameters Colour, Aromaticity TOC, DOC, BDOC Assimilable organic Carbon (AOC), Bacterial regrowth Functional groups Hydrophobicity/Hydrophilicity **Molecular weight distribution Analytical tools UV-visible spectrometry DOC analyser Bacterial regrowth potential GC-MS, Infra red spectrometry (FTIR), NMR Rapid refraction High performance Size Exclusion Chromatography (HPSEC)

6 Objectives 6 Focus on NOM-Metal complexation Historical research theme in our lab Innovative apparatus Study of the complexation of various NOM fractions with metal Impacts on drinking water processes Coagulation, membrane filtration, disinfection by-product formation, trace metal leaching, ion exchanges (MIEX), The effect of treatment processes on each fraction

7 Methodology 7 Analytical tools Size-Exclusion Chromatography HP-SEC Spectral Dectectors Elemental dectector (metals, P, Br, I.) UV Fluorescence ICP-MS Column: Bio SEC-5 Column Spherical, porous silica with hydrophilic polymeric coating

8 8 PWN pilot water samples (Andijk) Two separate treatment lines Raw water Raw water Clarification Suspended Ion Exchange (SIX) Ultrafiltration Ceramic Filtration (Ceramac)

9 Signal response (a.u) Signal response (a.u) Results Chromatograph for the two separate lines Humic substances Order of decreasing size Clarification Building blocks Low molecularweight acids Suspended Ion Exchange Biopolymers ultrafiltration Low molecularweight neutrals Retention time (min) Ceramac Retention time (min) Ceramic microfiltration removes the biopolymers (hardely seen with UV detector)

10 A B C D 6FE CFE 10 E CFI UFE UFI

11 Removal efficiency of UV absorbing components at 254 nm (aromatic & unsaturated structures) % 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% 100% Biopolymers Clarification 38% 4% Humic Substance 3% Building blocks Ultrafiltration Less absorption in UV 8% Lower mol wgt acids 17% 32% Lower mol wgt neutrals 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% 14% Ion exchange resin 100% Biopolymers 75% Humic Substance 70% Building blocks CeraMac (micro filteration) 78% Lower mol wgt acids 81% Lower mol wgt neutrals UV absorbance measurement not purely quantitative

12 Absorbance Signal response (a.u) Changes in spectral properties with NOM-metal complexation 12 0,6 Cu, Al, Zn, Mn from ~ 0 up to 150 µmol/l (11 samples) Zn Complexation -UV 25 Zn Complexation -HPLC 0,5 0,4 0,3 0,2 0,1 0 Inadequate information on the UV spectra Spectral shift Wavelenght nm Decrease of UV absorbance with metal addition Retention time (min) Shift of size of the Low molecular acids And increase of absorbance The quenching of UV absorbance is well documented not the shift of size

13 13 0,6 25 Al Complexation -UV Signal Response (a.u) Absorbance 0,5 0,4 0,3 0, Wavelenght nm Higher decrease of UV absorbance Shift of size of the Low molecular acids without absorbance modification 10 0,1 240 Al Complexation - HPLC 6 7 Retention time (min) Different behaviour : Al better complexant than Zn The quenching depends on the humic substance molecular weight 8

14 Excitation Cu complexation - Excitation emission matrix (EEM) fluorescence 14 [Cu] = 0µmol/L [Cu] = 4 µmol/l [Cu] = 40 µmol/l Humic-Like Protein-like Emission A decrease in fluoresence intensity with increase in metal concentration Matrix to be fully treated

15 Signal response (cps) Mn, Cr Signal response (cps) - Cu, As, Pb, Zn SEC-ICP-MS chromatograph - Andijk raw water, natural metal concentration Element Concentration (µg/l) Mn Cr Cu As Pb Retention time (min) 0 Zn 50.9 Mn Cr Zn Cu As Pb

16 Comparing UV and ICP-MS Chromatographs 16 UV-6FE UV-6FE Each metal deplays a Almost all fractions Cu Low mol. weight acids Cr peak corresponding to its complexed Building blocks Pb Building blocks Zn fraction

17 Signal response (cps) Signal response (cps) Cation competition for binding sites 17 [Cu] = 4.25 µg/l, [Zn] = 50.9µg/L Addition of 20 µg/l of Cu UFI 6000 UFI Cu 20ug/L Cu Zn Cu Zn Zn is no more complexed to NOM Retention time (min) Retention time (min)

18 Conclusions & Perspectives 18 HPSEC-UV-Fluorescence-ICP-MS Effective technique for understanding the characteristics of NOM, NOM-metal complexation & effect of treatment on each fraction Quantitative measurement of complexed metals- SEC-ICP-MS Well classify the various broad functional groups of my samples; SEC-ICP-MS Detailed explanation to the possible quenchings and shifts

19 Conclusions & Perspectives 19 Applicability; Impact on drinking water processes Coagulation Membrane filtration, Lime-soda softening Disinfection by-product formation, Trace metal leaching Ion exchanges (MIEX) Activated Carbon

20 20 Thank you

21 Reference 21 Abbt-Braun, G., Lankes, U. and Frimmel, F.H Structural characterization of aquatic humic substances The need for a multiple method approach. Aquatic Sciences 66, Aiken, G. and Cotsaris, E Soil and hydrology: Their effect on NOM. J. Am. Water Works Assoc. 87(1), Huber, S.A., Balz, A., Abert, M. and Pronk, W Characterisation of aquatic humic and non-humic matter with size-exclusion chromatography organic carbon detection organic nitrogen detection (LC-OCD-OND). Water Res. 45, Reemtsma, T., These, A., Springer, A. and Linscheid, M Differences in the molecular composition of fulvic acid size fractions detected by size-exclusion chromatography on line Fourier transform ion cyclotron resonance (FTICR ) mass spectrometry. Water Res. 42, Weishaar, J.L Evaluation of Specific Ultraviolet Absorbance as an Indicator of the Chemical