Microplastics in Aquatic Environments: Recent Advances in Separation Techniques

Abstract

Separation and removal of microplastic pollution from aquatic environments as a global environmental issue is classified as one of the major concerns in both water and wastewater treatment plants. Microplastics as polymeric particles less than 5 mm in at least one dimension are found with different shapes, chemical compositions, and sizes in soil, water, and sediments. Conventional treatment methods for organic separation have shown high removal efficiency for microplastics, while the separation of small microplastic particles, mainly less than 100 µm, in wastewater treatment plants is particularly challenging. This review aims to review the principle and application of different physical and chemical methods for the separation and removal of microplastic particles from aquatic environments, especially in water treatments process, with emphasis on some alternative and emerging separation methods. Advantages and disadvantages of conventional separation techniques such as clarification, sedimentation, floatation, activated sludge, sieving, filtration, and density separation are discussed. The advanced separation methods can be integrated with conventional techniques or utilize as a separate step for separating small microplastic particles. These advanced microplastic separation methods include membrane bioreactor, magnetic separation, micromachines, and degradation-based methods such as electrocatalysis, photocatalysis, biodegradation, and thermal degradation.

Metal–Organic Frameworks Marry Sponge: New Opportunities for Advanced Water Treatment

“…65,66 These solid particles carry hard-to-degrade contaminants, including microorganisms, microplastics, and heavy metal ions. 67 The ultrafine suspended solids within these particles (ranging from 0.1 to 100 μL) 68,69 can accumulate in human lungs 70 and directly enter the bloodstream, causing severe harm to human health. 71,72 In practice, we usually treat with traditional methods (mass sprinkling, flocculation, and membrane treatment).…”

“…Nano pollution, mainly arising from solid particles in the ground and soil, poses a significant environmental challenge. , These solid particles carry hard-to-degrade contaminants, including microorganisms, microplastics, and heavy metal ions . The ultrafine suspended solids within these particles (ranging from 0.1 to 100 μL) , can accumulate in human lungs and directly enter the bloodstream, causing severe harm to human health. , In practice, we usually treat with traditional methods (mass sprinkling, flocculation, and membrane treatment). , Because of the physical properties of ultrafine suspended solids themselves (especially those with particle sizes less than 1000 nm), this method causes problems with the membrane being clogged and unable to settle and flocculate, so the traditional method is not feasible.…”

Archives of Environmental Protection

“…Typically, the name microplastic refers to plastic particles between 100 nm and 5 mm in size (Saboor et al 2022). Based on particle size, plastics are classified into different categories, including macroplastics (>25 mm), mesoplastics (5-15 mm), microplastics (<5 mm) and nanoplastics (<100 nm) (Badola et al 2022, Saboor et al 2022. Manufactured particles, such as microbeads, enter directly into wastewater and are counted as primary MPs.…”

“…Manufactured particles, such as microbeads, enter directly into wastewater and are counted as primary MPs. On the other hand, plastics that are formed during the process of breakdown from solid plastic waste into smaller particles are considered as secondary MPs (Ahmed et al 2021, Saboor et al 2022. The most common plastic materials found in effluents are polypropylene (PP), polyethylene (PE), polystyrene (PS), polyvinyl-chloride (PVC), polycarbonate (PC), polyamides (PA), polyester (PES) and polyethylene terephthalate (PET), depending on the type of products produced by the plant (Talvitie et al 2017a,b).…”

“…The most common pore size in filters is 0.45-1 μm. Some filter materials have a curvy and deep pore structure, such as stainless steel and nylon filters, while others have narrow and straight circular pores, such as polycarbonate filters (Saboor et al 2022). Due to the microscopic size of the particles or contaminants in the liquid, filter cartridges become clogged.…”