US 12,281,032 B2
Method of evaluating and optionally selecting a suitable chemistry for removal of microplastics in a liquid matrix
Outi Gronfors, Espoo (FI); Mehrdad Hesampour, Espoo (FI); Katriina Rajala, Espoo (FI); and Lenita Lindberg, Espoo (FI)
Assigned to KEMIRA OYJ, Helsinki (FI)
Appl. No. 17/430,750
Filed by KEMIRA OYJ, Helsinki (FI)
PCT Filed Feb. 18, 2020, PCT No. PCT/EP2020/054217
§ 371(c)(1), (2) Date Aug. 13, 2021,
PCT Pub. No. WO2020/169591, PCT Pub. Date Aug. 27, 2020.
Claims priority of application No. 1950203-8 (SE), filed on Feb. 18, 2019; and application No. 4950532-0 (SE), filed on May 6, 2019.
Prior Publication US 2022/0135451 A1, May 5, 2022
Int. Cl. C02F 1/52 (2023.01); C02F 1/00 (2023.01); C02F 1/24 (2023.01); C02F 1/56 (2023.01); G01N 15/0205 (2024.01); G01N 33/18 (2006.01); C02F 101/32 (2006.01); C02F 103/00 (2006.01); G01N 15/00 (2006.01)
CPC C02F 1/5209 (2013.01) [C02F 1/001 (2013.01); C02F 1/24 (2013.01); C02F 1/5245 (2013.01); C02F 1/56 (2013.01); G01N 15/0211 (2013.01); G01N 33/18 (2013.01); C02F 2001/007 (2013.01); C02F 2101/32 (2013.01); C02F 2103/007 (2013.01); C02F 2209/003 (2013.01); C02F 2209/105 (2013.01); G01N 2015/0053 (2013.01); G01N 2015/0092 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A method of selecting a suitable chemistry for removal of microplastics in a liquid matrix, said method comprising the steps of:
a. providing a predetermined volume of a liquid matrix,
b. adding a preset amount of a chemical system comprising at least one coagulant and/or flocculant to the liquid matrix of step a), and allowing the added chemical system to interact to form flocs and/or aggregates containing any microplastic particles, if present in the liquid matrix,
c. removing flocs and/or aggregates containing any microplastic particles of the liquid matrix in a separation step to form a clarified liquid matrix,
d. measuring fluorescence intensity and light scattering intensity of any particles in a sample volume of clarified liquid matrix by an optical detection method comprising,
d′. gathering and combining the scattering intensity data and the fluorescence intensity data of the particles,
d″. identifying particle populations of the measured data representing microplastic particles populations based on predetermined identification data, and
d′″. determining the number of microplastic particles of the microplastic particles populations,
e. assessing the efficiency of microplastics removal based on:
the number of microplastic particles in the sample volume used in step d),
or
the number of microplastic particles in the sample volume used in step d) compared to a known number of microplastic particles, if used, added to the liquid matrix in step a);
and wherein steps a) to e) are repeated with other chemical systems than said at least one chemical system, and further comprising the steps of:
f. comparing the efficiency of microplastics removal of all chemical systems tested, and
g. based on these results selecting as the chemistry for removal of microplastics in a liquid matrix the chemical system which provides for the most efficient removal of microplastic particles.