Membranowy proces wymiany anionów jako metoda zmiany składu jonowego wody

• Autorzy: Kliber S. , Wiśniewski J. A.

Warianty tytułu

EN

Membrane process of anion exchange as a method of Ion composition conversion in water

• Języki publikacji: PL

Abstrakty

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).

Słowa kluczowe

PL

wymiana anionów; skład jonowy wody; membranowy proces

EN

anion exchange; ion composition of water; membrane process; process exchange

• Wydawca: Politechnika Koszalińska
• Czasopismo: Rocznik Ochrona Środowiska
• Rocznik: 2009
• Tom: Tom 11
• Strony: 995--1005
• Opis fizyczny: bibliogr. 12 poz.

Twórcy

autor

Kliber S.

autor

Wiśniewski J. A.

• Politechnika Wrocławska

Bibliografia

• 1. Garmes H., Persin F., Sandeaux J., Pourcelly G., Mountadar M., Defluoridation of groundwater by a hybrid process combining adsorption and Donnan dialysis. Desalination 145, 287-291, 2002.
• 2. Hichour M., Persin F., Molenat J., Sandeaux J., Gavach C., Fluoride removal from diluted solutions by Donnan dialysis with anion-exchange membranes. Desalination 122, 53-62, 1999.
• 3. Hichour M., Persin F., Sandeaux J., Gavach C., Fluoride removal from waters by Donnan dialysis, Separation and Purification Technology 18, 1-11, 2000.
• 4. Matos C. T., Velizarov S., Crespo J. G., Reis M. A., Simultaneous removal of perchlorate and nitrate from drinking water using the ion exchange membrane bioreactor concept. Water Research 40, 231-240, 2006.
• 5. Nightingale E.R., Phenomenological theory of ion solvation. Effective radii of hydrated ions, J. Phys. Chem., 63, 1381-1387, 1959.
• 6. Różańska A., Wiśniewski J., Winnicki T., Donnan dialysis with anion-excahnge membranes in a water desalination system, Desalination, 198, 236-246, 2006.
• 7. Strathmann H., Ion-exchange membrane separation processes. Membrane Science and Technology Series, 9, Elsevier, Amsterdam 2004.
• 8. Velizarov S., Reis M.A., Crespo J.G., Integrated transport and reaction in an ion exchange membrane bioreactor. Desalination 149, 205-210, 2002.
• 9. Velizarov S., Matos C., Reis M., Crespo J., Removal of inorganic charged micropollutants in an ion-exchange membrane bioreactor. Desalination 178, 203-210, 2005.
• 10. Wallace R.M., Concentration and separation of ions by Donnan membrane equilibrium. J. Phys. Chem., 6(4), 423-431, 1967.
• 11. Wiśniewski J., Ion exchange by means of Donnan dialysis as a pretreatment process before electrodialysis. Environment Protection Engineering, vol. 32, 2006.
• 12. Wiśniewski J., Różańska A., Donnan dialysis with anion-exchange membranes as a preatreatment step before electrodialytic desalination. Desalination, 191, 210-218, 2006.