Chemical Cleaning of Ultrafiltration Membrane Fouled by Humic Substances: Comparison between Hydrogen Peroxide and Sodium Hypochlorite

Abstract

Chemical cleaning is indispensable for the sustainable operation of ultrafiltration (UF) system in water and wastewater treatment. Sodium hypochlorite (NaClO) is an established cleaning agent for membranes subject to organic and microbial fouling, but concerns have been raised about the generation of toxic halogenated by-products during NaClO cleaning. Hydrogen peroxide (H2O2) is a potential “green” cleaning agent that can avoid the formation of halogenated by-products. In this work, cleaning efficacy of H2O2 and NaClO for UF membrane fouled by humic substances (HS) was evaluated under a wide pH range, and change of HS’s properties due to reaction with cleaning agents was examined. The cleaning efficacy of H2O2 was lower than that of NaClO at pH 3–9, but it increased to a level (91.4%) comparable with that of NaClO at pH 11. The extents of changes in properties and fouling potential of HS due to reacting with cleaning agents were consistent with their cleaning efficacy. H2O2 treatment at pH 11 significantly increased negative charge of HS molecules, decomposed high-MW molecules, and reduced its fouling potential. Therefore, considering treatment/disposal of cleaning waste and cleaning efficacy, H2O2 cleaning under strong alkaline condition can be a good choice for HS-fouled membrane.

Effects of Hydrogen Peroxide and Sodium Hypochlorite Aging on Properties and Performance of Polyethersulfone Ultrafiltration Membrane

“…Combining Figure 1, Figure 2 and Figure 3, it can be concluded that degradation of the PES membrane due to NaClO exposure was much more serious than that by H 2 O 2 exposure under the aging conditions in this work. Considering the comparable efficiency of H 2 O 2 cleaning with NaClO cleaning [18], H 2 O 2 is a better oxidative cleaning agent than NaClO because of the minimization of membrane degradation.…”

“…Hydrogen peroxide (H 2 O 2 ) is a strong oxidant with a standard reduction potential of 1.78 V, but its reactivity is restricted by a relatively high activation energy barrier [18,19]. Although its application as an oxidative cleaning agent is not as wide as that of NaClO, its effectiveness for permeability recovery has been demonstrated in several studies [20,21].…”

“…Although its application as an oxidative cleaning agent is not as wide as that of NaClO, its effectiveness for permeability recovery has been demonstrated in several studies [20,21]. It was found that H 2 O 2 cleaning under strong alkaline condition can achieve comparable cleaning efficacy with NaClO for cleaning of UF membrane fouled by humic substances [18]. Moreover, compared with NaClO cleaning, H 2 O 2 cleaning can avoid the formation of toxic halogenated by-products.…”

Reducing the Impacts of Biofouling in RO Membrane Systems through In Situ Low Fluence Irradiation Employing UVC-LEDs

“…The cleaning of the system included flushing with 0.1% NaOH (Merck, Darmstadt, Germany) to remove organic matter [ 71 ]. Sterilization was done by autoclaving at 121 °C for 20 min or soaking in 0.25% H 2 O 2 solution (Merck, Darmstadt, Germany), analogous to [ 71 , 72 , 73 , 74 , 75 ]. Reassembling of the skid: After cleaning and sterilization, the skid was reassembled under sterile conditions.…”

Protein recovery as a resource from waste specifically via membrane technology—from waste to wonder

“…Also, it is more likely that most of the pollutants that stick on the surface of the membrane were soluble to the permeate (Beyer et al 2017 ). The other method used for the sustainable operation of the membrane process is chemical cleaning of both UF and NF membranes, using different chemical agents such as sodium hypochlorite (NaClO) (Li et al 2019a ), which is effective for membrane fouling via organic wastewater treatment and microbial fouling (Malczewska and Żak 2019 ). Table 11 presents the cost analysis of protein recovery using membrane technology from different waste streams.…”