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Wykorzystanie pyłowego węgla aktywnego oraz selektywnego anionitu do zwiększenia skuteczności usuwania związków organicznych z wody po procesie koagulacji

Pruss A., Pruss P.

Ochrona Środowiska

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2016

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Vol. 38, nr 1

25–-28

PL

Określono możliwość zmniejszenia zawartości ogólnego węgla organicznego (OWO) w wodzie powierzchniowej przez dawkowanie pyłowego węgla aktywnego (PWA) przed filtracją pospieszna i wymianą jonową na selektywnym anionicie DOWEX™ TAN-1. Badania prowadzono równolegle w dwóch przepływowych układach modelowych. Pierwszy składał się z filtru pospiesznego oraz kolumny jonitowej, natomiast drugi z kolumny kontaktowej, przed którą dawkowano PWA, filtru pospiesznego oraz kolumny jonitowej. Do zasilania obu układów wykorzystano wodę po koagulacji w instalacji z flotacją realizowaną w pilotowej skali technicznej o wydajności 25 m3/h, zastosowanej do oczyszczenia wody powierzchniowej o małej zasadowości, dużej zmienności temperatury i okresowo bardzo dużej zawartości substancji organicznych. Na podstawie zmian zawartości w wodzie OWO oraz frakcji substancji organicznych wykazano, że zastosowanie po koagulacji adsorpcji na PWA w ilości do 20 g/m3 oraz po filtracji wymiany jonowej na selektywnym anionicie umożliwiło zmniejszenie ilości OWO w oczyszczonej wodzie do wartości poniżej 1 gC/m3.

EN

A possibility of TOC reduction in surface water through powdered activated carbon (PAC) dosing prior to the rapid filtration and ion exchange using selective anionite DOWEX™ TAN-1 was determined. The studies were conducted in two parallel flow-through model systems. The first system consisted of a rapid filter and an ion exchange column, while the second included PAC dosage point prior to a contact column, a rapid filter and an ion exchanger. Both systems were supplied with water after coagulation in installation with flotation implemented in a pilot industrial scale of 25 m3/h capacity. It was used for treatment of surface water with low alkalinity, high temperature variation and periodically very high organic content. On the basis of TOC and organic matter content variations in water it was demonstrated that application of adsorption on PAC in doses up to 20 g/m3 after coagulation process, and selective ion exchange following filtration made it possible to reduce the TOC amount in the treated water to the level below 1 gC/m3.

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Radio Analytical Nondestructive Technique in Performance Evaluation of Organic Base Ion Exchange Resins Purolite NRW-6000 and Duolite A-378

Singare P. U.

International Letters of Chemistry, Physics and Astronomy

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2013

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Vol. 13

77-89

EN

Nondestructive radioanalytical technique using short lived isotopes 131I and 82Br was used as tracers to study the kinetics of iodide and bromide ion-isotopic exchange reactions. The kinetic data so obtained was used to evaluate the performance of organic base anion exchange resins Purolite NRW-6000 and Duolite A-378. It was observed that for iodide ion-isotopic exchange reaction performed at 40.0 °C using 1.000 g of ion exchange resins and 0.003 mol/L labeled iodide ion solution, the values of specific reaction rate (min-1), amount of iodide ion exchanged (mmol), initial rate of iodide ion exchange (mmol/min) and log Kd were calculated as 0.332, 0.582, 0.193 and 16.2 respectively for Purolite NRW-6000 resin, which was higher than the respective values of 0.210, 0.421, 0.088 and 14.7 as that obtained for Duolite A-378 resins. Also at a constant temperature of 40.0 °C, as the concentration of labeled iodide ion solution increases from 0.001 mol/L to 0.004 mol/L, the percentage of iodide ions exchanged increases from 74.68 % to 79.48 % using Purolite NRW-6000 resins and from 52.30 % to 58.90 % using Duolite A-378 resins. The overall results indicate superior performance of Purolite NRW-6000 resins over Duolite A-378 resins under identical operational parameters. It is expected here that the present technique can be extended further for characterization of different ion exchange resins which will further help in the selection of those reins for the specific industrial application.

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Nondestructive Radioactive Tracer Technique in Characterization of Anion Exchange Resins Purolite NRW-8000 and Duolite A-368

Singare P.U.

International Letters of Chemistry, Physics and Astronomy

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2013

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Vol. 12

14--27

EN

Radioactive tracer isotopes 131I and 82Br were used to characterize anion exchange resins Purolite NRW-8000 and Duolite A-368 by application of nondestructive technique. The resin characterization was based on their performance during iodide and bromide ion-isotopic exchange reactions. It was observed that during the iodide ion-isotopic exchange reaction at a constant temperature of 40.0 °C, as the concentration of labeled iodide ion solution increases from 0.001 mol/L to 0.004 mol/L, the percentage of iodide ions exchanged increases from 62.10 % to 68.10 % using Purolite NRW-8000 resins and from 44.20 % to 46.80 % using Duolite A-368 resins. Also at a constant temperature of 40.0 °C, 1.000 g of ion exchange resins and 0.003 mol/L labeled iodide ion solution, the values of specific reaction rate (min-1), amount of iodide ion exchanged (mmol), initial rate of iodide ion exchange (mmol/min) and log Kd were calculated as 0.260, 0.500, 0.130 and 11.8 respectively for Purolite NRW-8000 resin, which was higher than the respective values of 0.130, 0.345, 0.045 and 6.7 as that obtained for Duolite A-368 resins. The similar trend was observed for the two resins during bromide ion-isotopic exchange reaction. From the overall results it appears that under identical experimental conditions, Purolite NRW-8000 resins show superior performance over Duolite A-368 resins. It is expected here that the present nondestructive technique can be extended further for characterization of different industrial grade ion exchange resins, which will help in their selection for specific industrial application.

4

Membranowy proces wymiany anionów jako metoda zmiany składu jonowego wody

Kliber S., Wiśniewski J. A.

Rocznik Ochrona Środowiska

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2009

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Tom 11

995-1005

PL

Celem pracy było określenie wpływu wybranych parametrów procesowych (ze szczególnym uwzględnieniem temperatury) na efektywność usuwania uciążliwych anionów (azotanów, siarczanów i wodorowęglanów) z roztworów wodnych w procesie dializy Donnana z membraną anionowymienną. Azotany są szkodliwe dla zdrowia człowieka, toteż ich stężenie jest ściśle normowane w wodzie do picia. Z kolei siarczany i wodorowęglany są jonami uciążliwymi ze względu na odsalanie wody, ponieważ mogą wytrącać się w postaci osadów: CaSO4 i Ca(HCO3)2, na powierzchni membran. Zatem wymiana tych anionów na jony obojętne (tj. chlorki) w procesie dializy Donnana pozwala na bardziej efektywne odsalanie wody słonawej metodą elektrodializy.

EN

Qualification of influence of selected process parameters (with special regard of temperature) on efficiency of noxious anions (nitrates, sulphates and bicarbonates) removal from aqueous solutions in the process of Donnan dialysis with anion-exchange membrane was the aim of the work. Nitrates are harmful for human health, therefore their concentration is closely standardized in the drinking water. Sulphates and bicarbonates are noxious ions during desalination of water, because they can precipitate in the form of CaSO4 and Ca(HCO3)2, on surface of membranes. Therefore exchange of those anions on inactive ones (e.g. chlorides) during Donnan dialysis allows to desalinise salty water with application of electrodialysis more effectively. Donnan dialysis (DD) is ion-exchange membrane technique which consists in exchange of ions with the same sign between two solutions divided by ion exchange membrane. Gradient of chemical potentials of solutions on two sides of membrane is the driving force of process. Donnan dialysis with anion-exchange membrane is at present applied for removal of fluorides from water [1, 2, 3]. The process allows to conduct effective defluorisation. Fluorides concentration after the process is lower than admissible value (1.5 mg/dm3). Donnan dialysis process with the anion-exchange membrane (Selemion AMV) was applied for the removal of troublesome anions (NO3-, SO42-, HCO3-) from water solutions. It was found that ions removed with the highest rate are nitrates, however sulphates are removed with the highest efficiency (91%). As a result of anion exchange, advantageous conversion in the water ionic composition occurs: molar share of sulphates decreases from 25,8 to 2,1%, molar share of nitrates - from 28,1 to 5,2% and that of bicarbonates - from 24,1 to 11,2%. It was observed that the increase of NaCl concentration (from 100 to 300 mM) in the receiving solution caused the increase of removed anion flux as well as the process efficiency. Analyzing the effect of the solution temperature on the Donnan dialysis process it was found that with the higher temperature of the solutions, anion exchange was faster: average flux of nitrates and sulphates increased by 50-60% and that of bicarbonates increased by over 90% (with the increase of temperature from 17 to 37°C).

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Usuwanie bromianów z roztworów wodnych w membranowym procesie wymiany anionowej

Wiśniewski J., Kliber S.

Ochrona Środowiska

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2009

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Vol. 31, nr 2

35-39

PL

Przedstawiono wyniki badań nad usuwaniem bromianów z roztworów wodnych w membranowym procesie wymiany anionowej. Proces dializy Donnana przeprowadzono w laboratoryjnej instalacji do dializy (Goemasep 136) wyposażonej w 20 par komór z membranami anionowymiennymi Selemion AMV, Neosepta AFN i Neosepta ACS. Największą skuteczność usuwania bromianów - 89% i 100% - uzyskano stosując membranę Selemion AMV, odpowiednio przy stężeniach NaCl w roztworze odbierającym 200 mol/m3 i 300 mol/m3. Zaobserwowano, że proces wymiany anionów przy użyciu membrany Neosepta AFN (charakteryzującej się luźną strukturą) przebiegał z większą szybkością, lecz skuteczność usuwania bromianów była mniejsza. Zastosowanie w procesie wymiany anionów membrany Neosepta ACS (o zwartej strukturze powierzchniowej) spowodowało, że zarówno szybkość, jak i skuteczność usuwania anionów (w tym bromianów) były najmniejsze spośród badanych membran. Wykazano, że proces wymiany anionowej na membranach anionowymiennych umożliwił skuteczne usunięcie z wody szkodliwych bromianów i azotanów i zastąpienie ich jonami neutralnymi (chlorkami). Szybkość i skuteczność usuwania anionów z wody w tym procesie zależała m.in. od rodzaju membrany anionowymiennej i stężenia NaCl w roztworze odbierającym.

EN

The objective of the study was the removal of bromates from water solutions by an anion-exchange membrane process. Donnan dialysis was conducted in a laboratory dialytic set-up (Goemasep 136) equipped with 20 cell pairs and three types of anion-exchange membranes: Selemion AMV, Neosepta AFN or Neosepta ACS. The highest efficiencies of bromate removal, 89% and 100%, were obtained with Selemion AMV, at NaCl concentrations in the receiving solution amounting to 200 mol/m3 and 300 mol/m3, respectively. It has been observed that when use was made of the Neosepta AFN membrane (characterized by a loose structure), anion exchange proceeded at a faster rate as compared to the other membranes tested, but the efficiency of bromate removal was lower. The application of the Neosepta ACS membrane (of a dense surface structure) produced the lowest values of both rate and efficiency of anion removal (including those for bromates). It has been demonstrated that the process of anion exchange conducted with anion-exchange membranes not only brought about a highly efficient removal of the harmful bromates and nitrates from the water, but also enabled their substitution with neutral ions (chlorides). The rate and efficiency with which the anions were removed during the process depended, inter alia, on the type of the anion-exchange membrane and the concentration of NaCl in the receiver.