Ammonia recovery from agricultural wastes by membrane distillation: Fouling characterization and mechanism

Fouling analysis and control in a DCMD process for SWRO brine

“…The peak 1084 cm −1 is indicative of alcohol groups in carbohydrates emanating from polysaccharide [14][15][16]. Proteins were represented by secondary amides at the peaks of 1481, 1489, 1498 cm −1 or carboxylic acid group at 1614 cm −1 [17][18][19]. The peak at wave numbers of 854, 856 cm −1 indicates the hydrogen-bonded OH stretching vibration of carboxylic groups reflecting the humic substances [20].…”

“…However, NaCl is among the salts to form on the membrane surface in cases of drying out membranes [23]. The organic and inorganic foulants adhered on the membrane surface with the existence of the divalent cations (Ca 2+ and Mg 2+ ) can strengthen the fouling layer, as they may act as bridging ions between the protein fouling layer and hydrophilic side chains of polysaccharides, proteins, and humic like substances to create a highly compacted fouling layer [17]. In addition, during the MD process, macromolecules such as humic or hydrophobic fraction of the organic foulants as well as less negatively charged organic fouling constituents such as the aforementioned calcium-bound organic matter preferentially can deposit onto the negatively charged membrane surface.…”

Cleaning ceramic membranes used in treating desizing wastewater with a complex-surfactant SDBS-assisted method

“…6, the main resistance that led to flux decline was the concentration polarization resistance, which can be recovered by rinsing the membrane with pure water. It can be explained by the disruption of the boundary layer, the increase in back-diffusion of the feed solution, and the decrease in osmotic pressure [16,38,39]. The industrial membrane system operation results also showed that the flux could be well recovered using hot water (about 60-80°C) cleaning after filtration step.…”

“…However, membrane fouling is one of the main obstacles to the stable operation of membrane separation plant. Researches have shown that membrane fouling can cause decline in permeate flux and water quality, and increase in the operating pressure, which ultimately increases the operational costs [14][15][16][17]. A general classification of membrane fouling includes colloidal fouling, biofouling, organic fouling and inorganic fouling.…”

Fouling in Membrane Distillation, Osmotic Distillation and Osmotic Membrane Distillation

“…The membrane having higher values of crystallization fouling factor exhibited the lower value of the water contact angle. Zarebska, et al [58] measured the water contact angles of new and fouled PP membranes used in MD. Figure 4 shows the water drops on the surface of these membranes.…”