Fouling mechanizm of immersed membrane for arsenic removal from water

Kombinacija adsorpcije na Fe(OH)3 i mikrofiltracije je vrlo učinkovita metoda za uklanjanje arsena iz vode za piće. U ovom radu istraživano je čepljenje membrane uronjene u suspenziju Fe(OH)3, metodom određivanja kritiĉnog fluksa pri različitim uvjetima aeracije i koncentracijama filtrirane tvari u suspenziji. Cilj istraživanja bio je odrediti optimalne uvjete pri kojima bi rad u hibridnom sustavu imerzne membranske filtracije bio održiv kroz dulji vremenski period. Iz dobivenih rezultata utvrđeno je da se kritični fluks povećavao s povećanjem inteziteta aeracije i sa smanjenjem koncentracije suspenzije u koju je membrana uronjena. Radom pri subkritičnom fluksu, visokoj koncentraciji suspenzije i intezitetu aeracije, proces se pokazao održivim tijekom sedam dana, bez zaustavljanja i čišćenja membrane. Pri ovim uvjetima došlo je do sporog, ali kontinuiranog čepljenja membrane, što se vidi i iz permeabilnosti membrane koja se tijekom filtracije suspenzije smanjila za 57,7 %. Pranjem membrane s otopinom oksalne kiseline bilo je moguće potpuno očistiti membranu.The combination of adsorption on Fe(OH)3 and microfiltration is very effective method for arsenic removal from drinking water. In this study I investigated fouling of the membrane immersed in a suspension of Fe(OH)3, by determining the critical flux under different conditions of aeration and suspended matter concentration. The aim of this study was to determine the optimal conditions in which process would be sustainable over a long period of time. From the results it was found that the critical flux increased with increasing intensity of aeration and with decreasing concentration of suspension in which the membrane was immersed. Working at subcritical flux, high concentration of suspension and intensity of aeration, the process has proven to be sustainable over seven days without stopping and cleaning the membrane. In these conditions, slow but continuous fouling has occurred, as seen from the permeability of the membrane which has decreased by 57,7%. By washing the membrane with a solution of oxalic acid it was possible to completely clean the membrane