|
| MP purification technologies | Removal efficiency | Advantages | Limitation | Reference |
|
| Physical methods of removal |
| Rapid sand filtration (RSF) | 97% | This filter removes suspended particles, microorganisms, and nutrients. It is effective in filtering small particles | It is necessary to add a coagulant to improve the adhesive ability | [109] |
| Dissolved air flotation (DAF) | 95% | Low investment costs due to compact design, short retention time, and small dimensions of flocculation and flotation chambers | There are concerns about how interactions between bubbles/particles (aggregates), particularly in relation to adhesion through hydrophobic forces, work | [68] |
| Disc filter (DF) | 89.7% | It has lower energy consumption, high resistance to various chemical contaminants, and is effective in reducing the presence of microplastics in wastewater effluents | Needs to be cleaned through high-pressure backwashing or using sodium hypochlorite to remove sludge buildup | [110, 111] |
| Ultrafiltration | 86–97.96% | High retention capacity, optimal recovery rate, high-speed filtration, versatility in different application contexts, reduced cost, and absence of phase transfer | Water passing through the membrane forms a concentrated polarization layer, which negatively affects filtration efficiency due to fouling | [112, 113] |
| Dynamic membrane (DM) | 99% | Low resistance to filtration, low transmembrane pressure, ease of operation, and absence of chemical treatment | Due to its oily nature, frequent cleaning is necessary to prevent excessive membrane fouling and sediment accumulation, which leads to high-energy consumption | [99] |
| Magnetic nanoparticle method | <92% | By removing organic, inorganic, microbial, and microplastic pollutants from water, the magnetic compound can be easily retrieved using a conventional magnet | It causes fragmentation of more fragile particulate matter and requires filtration suitable only for small water volumes | [103, 114, 115] |
|
| Chemical methods of removal |
| Coagulation/flocculation | 61% | Suitable for removing small microparticles, operating under adjustable conditions, and utilizing simple mechanical mechanisms | Chemicals must be added to the medium for small microplastics | [116] |
| Electrocoagulation | >90% | No risk of contamination, effective for small particle removal, cost-efficient, and flexible for automation while minimizing sludge | Repeated replacement of sacrificial anodes is necessary to prevent cathode passivation. In addition, this product is not suitable for use in areas without access to electricity | [100] |
| Micromotors | 67% | Water is utilized as a nontoxic source for the effective removal of suspended particles and microplastics, while sunlight is harnessed as a renewable energy resource | It takes a chain of magnetic clusters to overcome obstacles and lacks selectivity | [117, 118] |
| Microsubmarines | 70% | Sustainability is demonstrated through recycling and the elimination of oil and microplastic pollution | Microsubmarines have limited transportation capacity, thus requiring the combination of multiple microsubmarines in order to achieve sufficient capacity | [119, 120] |
|
| Biological methods of removal |
| Oxidation ditches | 97% | Compared to other biological treatment methods, sludge generation is reduced and less energy is consumed during the process | This method is highly efficient in smaller facilities but requires more space than traditional treatment plants | [108, 121] |
| Anaerobic, anoxic, and aerobic (A2O) | 72–98% | High organic loads can be handled with minimal sludge production | The anaerobic treatment process requires sufficient time to become effective | [104, 122] |
| Membrane bioreactors (MBR) | 99.9% | It is capable of removing high levels of biological oxygen demand (BOD) and chemical oxygen demand (COD) from a variety of wastewater compositions | One of the major issues is the inability to eliminate contaminants that are resistant to removal | [123, 124] |
| Sequential batch reactor (SBR) | 92.74% | It offers an affordable solution for achieving lower levels of effluent contaminants, allowing for easy expansion and simple operation with low capital costs | Effective aeration control is essential for optimal SBR efficiency, and the presence of sand can hinder this process | [125] |
| Conventional activated sludge (CAS) | 95–99.9% | The treatment is cost-effective, adaptable to various tributary concentrations, and resistant to changes | The tank’s long residence times, large settling surface, and high-energy consumption result in costly sludge processing and disposal | [98, 126] |
| Adsorption on green microalgae | 94.5 | The cut surfaces show a strong ability to attract small microplastic particles, and the selection is based on the surface charge of these microplastics | Nonreusable method, with microplastics that chemically adhere to the surface, potentially contaminating it | [127, 128] |
| Fungal degradation | 59% of the weight of the MPs | Natural decomposition through enzymes produced by fungi | The removal of MPs takes a long period, as it only becomes significant after an incubation period of 280 days at a temperature of 25°C | [129, 130] |
| Bacterial degradation | 20.4–97% | The application of bacteria is highly selective, reducing the likelihood of generating harmful byproducts. Furthermore, it consumes less energy and is more cost-effective than chemical procedures and applicable in a variety of contexts | Sometimes, the elimination of contaminants is not complete, and the process can be prolonged. Furthermore, it can be difficult to identify the right group of bacteria for efficient removal of MPs | [131–133] |
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