Iron amended gravity-driven membrane (IGDM) system for heavy-metal-containing groundwater treatment

Reduction of Ultrafiltration Membrane Fouling by the Pretreatment Removal of Emerging Pollutants: A Review

“…As a pretreatment process, adsorption has the outstanding advantages of low cost, high efficiency, and no driving force, but also has the disadvantages of high regeneration costs and easy secondary release [ 79 ]. Through the combination of adsorption and ultrafiltration (A-UF), the process originally belonging to two units can be integrated into one process, reducing the footprint of the water purification unit [ 18 , 20 , 25 , 74 ]. Carbon-based materials have the characteristics of high-specific surface area and many adsorption sites.…”

“…They can adsorb various pollutants through hydrophobic interaction, hydrogen bonding, and π–π stacking [ 20 ]. Due to the characteristics of the large specific surface area and the low particle size of pretreatment materials, improper use will lead to the deposition of adsorption materials on the surfaces of UF membranes, which will further aggravate membrane pollution [ 18 , 25 , 74 ]; therefore, A-UF has high requirements regarding the combination of materials and the actual operation process.…”

“…When the rust falls off, a new iron surface will be exposed, and the adsorption process will continue. The fallen rust will be completely rejected by the UF film [ 18 ]. The results revealed that the thickness of the filter cake layer increased by 143%, the content of adenosine triphosphate decreased by 75%, the removal rate of HMIs exceeded 90% (iron adsorption > 80%), and the rust was able to prevent bacteria growth [ 18 ].…”

“…Ultrafiltration (UF) processes represent a water purification method that is able to achieve relative energy savings, and which is widely used in biological protein separation, medical treatments, and wastewater purification [ 1 , 12 , 13 , 14 ]. Based on the interception effect of UF membranes on organics with different molecular weights, these processes can be adopted to separate macromolecular organics such as proteins, nucleic acids, polysaccharides, humic acids (HAs), and bacteria in wastewater purification [ 12 , 13 , 15 , 16 , 17 , 18 , 19 ]. Yasui et al reported that adopting UF strategies to remove the median of viruses can achieve 2.9 log, much lower than the indicators of human enteroviruses [ 19 ].…”

“…In addition, the staggered state between pores will further increase the compromise of the latter on the interception effect. As one of the main consumables, the filter membrane significantly changes the membrane flux and retention capacity due to the adsorption, blockage, corrosion, and other effects of pollutants [ 12 , 18 , 31 ], resulting in an inability to achieve 100% reuse, which seriously affects the costs of UF processes when they are in actual use [ 32 , 33 ]. Membrane pollution can be divided into reversible membrane pollution and irreversible membrane pollution.…”