SHORT RESEARCH AND DISCUSSION ARTICLE
A new approach for the agglomeration and subsequent removal
of polyethylene, polypropylene, and mixtures of both from freshwater
systems – acasestudy
Adrian Frank Herbort
Michael Toni Sturm
Received: 2 August 2017 / Accepted: 9 April 2018 / Published online: 19 April 2018
Springer-Verlag GmbH Germany, part of Springer Nature 2018
Based on a new concept for the sustainable removal of microplastics from freshwater systems, a case study for a pH-
induced agglomeration and subsequent removal of polyethylene and polypropylene particles from water is presented. The
two-step-based process includes firstly a localization and secondly an aggregation of microplastic particles (250–
350 μM) in a physicochemical process. The research describes a strong increase in the particle size independent of
pH of the aquatic milieu induced by the addition of trichlorosilane-substituted Si derivatives. The resulting Si-based
microplastic aggregates (particle size after aggregation is 2–3 cm) could be easily removed by use of, e.g., sand traps.
Due to the effect that microplastic particles form agglomeration products under every kind of process conditions (e.g.,
various pH, various polymer concentrations), the study shows a high potential for the sustainable removal of particles
Inert organic chemical pollutants
Since the start of the mass production of plastic in 1950 with
1.7 million t per year, the worldwide plastic production in-
creased to 311 million t per year in 2014 with a continuously
increasing tendency (PlasticsEurope 2015). High amounts
of incorrectly disposed plastic waste are released into the
environment every year accumulating in all parts of the
aquatic environment due to their slow degradation rates
(Barnes et al. 2009; Jambeck et al. 2015;Wrightetal.
2013). Ninety percent (by particle count) of the plastic
particles floating in the seas are classified as microplastics
(Eriksen et al. 2014). Per definition, microplastic is clas-
sified as plastic particles smaller than 5 mM (Barnes et al.
2009; Eerkes-Medrano et al. 2015). Microplastic particles
can result from the fragmentation of larger plastic items
influenced by different degradation processes in the envi-
ronment or can be released directly as microplastic parti-
cles into the environment (Fig. 1).
Most of the microplastics are categorized as persistent
stressors or inert organic chemical stressors (IOCS) on contact
with the ecosystem (Herbort and Schuhen 2016, 2017a).
These particles have various effects on the aquatic environ-
ment (Table 1).
Due to their physicochemical properties and high surface/
volume ratio, microplastics can adsorb and enrich different
pollutants from the surrounding water (Avio et al. 2016;
Schwarzenbach et al. 2006;Napperetal.2015). This can lead
to the transport of pollutants over large distances (Zarfl and
Matthies 2010; Bakir et al. 2014). The accumulation of organ-
ic pollutants depends on the type of polymer and the affinity of
contaminants to the polymer (Bakir et al. 2012). Observations
show that polyethylene (PE), polypropylene (PP), and poly-
styrene (PS) adsorb the highest amounts of organic pollutants.
Sorption into the polymeric matrix was proven for PE,
polyoxymethylene (POM), and PS, which causes an increased
sorption capacity for these polymer types (Pascall et al. 2005;
Karapanagioti and Klontza 2008).
Responsible editor: Philippe Garrigues
* Katrin Schuhen
Institute for Environmental Sciences, University of Koblenz –
Landau, Fortstr. 7, 76829 Landau in der Pfalz, Germany
Environmental Science and Pollution Research (2018) 25:15226–15234