Technological Approaches for the Reduction of Microplastic Pollution in Seawater Desalination Plants and for Sea Salt Extraction

Abstract

An increasingly serious and widespread problem is the introduction of plastics into the water cycle. The poor degradability leads to the plastic waste remaining in water for a long time and over time it fragments into smaller and smaller plastic particles. Both the visible plastic parts and in particular their decomposition products and functionalized plastic particles are an enormous burden. Seawater desalination and sea salt extraction are highly dependent on the quality of the seawater in terms of process utilization and cost structures, i.e., on the level of pollution. Especially microparticles represent a significant potential for blocking the microfiltration membranes (pore size > 100 nm) in the pretreatment and the very costly reverse osmosis (RO) membranes (pore size > 5 nm). An innovative approach for the removal of microplastics from industrially used seawater combines a chemically induced agglomeration and a new technological implementation step. The particular challenge in removing the synthetic impurities is not only their small size but also their inert properties against most of the physical and chemical additives for flocculation. With an easy implementation to existing systems, an economic aspect and a strong impact on the maritime ecological balance will be expected.

Increased plastic pollution due to COVID-19 pandemic: Challenges and recommendations

“…Wastewater treatments seem to eliminate a considerable percentage of plastic debris, but there is still a need of complementary treatments when considering particles of smaller size such as microplastics [103]. With this purpose, and in addition to the membrane treatments and filtrations already applied, the application of cleaner technologies, such as the application of membrane processes, regenerative filters systems or precipitation with magnetic nanoparticles, and application of inorganic-organic hybrid silica gels -organosilanes, have been developed and proved to be successful [103][104][105][106]. There are other experimental techniques that are being devolved for this purpose, such as dynamic membranes, photocatalysis, elimination with fats and constructed wetlands (a horizontal subsurface-flow that uses vegetation, soil and organisms to treat wastewater) [103].…”

Micro-plastics: An invisible danger to human health

“…Removal of microplastics waste from oceans is actually a challenge. But use of downstream Reverse osmosis membranes is considered by the researchers [40]. Except the use of RO membranes the Waste water treatment plants is also comes under recommendation as it is an efficient techniques to reduce the microplastic waste [41].…”

Removal of Microplastics from Waters through Agglomeration-Fixation Using Organosilanes—Effects of Polymer Types, Water Composition and Temperature

“…Facing this challenge, Herbort et al 2016 developed a new approach to remove microplastics from water using organosilanes ( Figure 1) [24][25][26][27][28]. The organosilanes consist of one organic group and three reactive groups.…”

“…So far the process has been tested to remove polyethylene and polypropylene based microplastics on lab scale using demineralized water and on pilot plant scale from tap water [25,27]. To investigate the transferability to processes in sea water and wastewater, it is tested how water compositions affect the removal process, as dissolved ions, natural organic matter or surfactant compounds can affect the sol-gel process and thus the removal process [28]. Also, the influence of water temperatures is tested, as it can vary depending on climatic conditions or wastewater origin.…”