Retention of organic matter by cellulose acetate membranes cleaned with hypochlorite

Degradation of polymeric membranes in water and wastewater treatment

“…Signifi cant peak reduction compared to virgin membrane suggests the oxidative degradation of CA to form carboxyl, aldehydes and ketone end products, also confi rmed by XPS studies (Arkhangelsky et al, 2008). In addition, a decline in mechanical strength (2006) PA Electrophilic substitution of the aromatic ring/chlorination of amide nitrogen followed by rearrangement to form ring chlorinated products Glater et al (1994), Soice et al (2003), Gabelich et al (2005) PVP Chain scission and oxidation of PVP leading to ring opening of pyrrolidine Wienk et al (1995) and pore enlargement was also demonstrated as a consequence of oxidative degradation.…”

“…Membrane degradation caused by chemical exposure is generally observed to embrittle the macromolecules resulting in the loss of material ductility (Arkhangelsky et al, 2008(Arkhangelsky et al, , 2007a(Arkhangelsky et al, , 2007bGaudichet-Maurin and Thominette, 2006;Rouaix et al, 2006;. However Wang et al (2010) reported the reverse; hypochlorite exposure of PVDF membranes resulted in a decline of tensile strength and Young's modulus, but ultimate elongation increased revealing that the membrane becomes more fl exible.…”

“…The attenuated total refl ectance (ATR)-FTIR spectrum of CA membranes exposed to 18 g h l -1 hypochlorite showed a considerable reduction in the intensities of characteristic peaks corresponding to the O-C-O vibration (1760 cm -1 ), C-O vibration (1230 cm -1 ) and C-H vibration (1340 cm -1 ) (Arkhangelsky et al, 2007a(Arkhangelsky et al, , 2008. Signifi cant peak reduction compared to virgin membrane suggests the oxidative degradation of CA to form carboxyl, aldehydes and ketone end products, also confi rmed by XPS studies (Arkhangelsky et al, 2008).…”

“…Attenuated total refl ectance -ATR -FTIR and XPS are two complementary techniques that are used by researchers to elucidate the chemical modifi cation mechanism and degradation of membranes Leckie, 2006a, 2006b;Antony et al, 2010;Arkhangelsky et al, 2008Arkhangelsky et al, , 2007bKang et al, 2007;Puspitasari et al, 2010;Rouaix et al, 2006). ATR -FTIR allows the detection of changes in the functional groups of the membrane by detecting bonds between atoms in a molecule and thus providing information about the functional groups and chemical structures of the membrane.…”

Separation of metal ions by complexation-microfiltration process

“…Ova ograničenja obuhvataju pH, temperaturu, toleranciju na hlor i peroksid. Kada se odrede granice tolerancije određenog membranskog sistema i odaberu odgovarajuća sredstva za čišćenje membrane, može se početi sa postupkom za čišćenje [88]. Glavni faktori koje treba uzeti u obzir su zapremina i koncentracija sredstva za čišćenje, kao i redosled, temperatura, protok i trajanje čišćenja.…”