Colloid Filtration

Introduction

As microscopically dispersed insoluble suspended particles, colloids have characteristic sizes between 1 nm and 1 µm. Colloids are composed of particles, surfactants, and polymers, and can be in three different phases (solid, liquid, and gas). Surface interactions for colloid filtration fall into two categories: colloid-surface interactions and colloid-colloid interactions. Alfa Chemistry's microfluidic membrane filtration technology enables breakthrough understanding of colloidal hydrodynamic effects, localization of colloidal particle capture and quantification of physicochemical interactions that occur at the pore scale during colloidal membrane filtration.

Fig. 1 (a) Colloid–surface interaction; (b) Colloid–colloid interactions.^[1]

Our Abilities

Microfluidic membrane filtration devices manufactured by Alfa Chemistry can be applied to nanoparticle separation, chemical sensors, removal of macromolecules and aggregates, electrophoresis and DNA separation. Our manufacturing methods can be divided into three categories:

• Production of Sieves

We can produce sieves using materials such as PDMS, hydrogels, paper, Si, zeolite and alumina. Specific methods include inserting membranes with desired pore sizes on the chips; direct casting of sieves made of permeable membranes and direct casting of sieves made of impermeable membranes.

Fig. 2 (a)A schematic of the microfluidic device; (b) Schematic of layer sequence starting from bottom to top; (c) Schematic of a double-filtration microfluidic device.^[1]

• Production of an Array of Pillars or Structures

A microfluidic membrane filtration device made of a series of parallel columns or microcolumns.

• Membrane-Less Filtration

Filtration methods that use inertial flow, solute gradient, two-phase or multi-phase flow to form a liquid film.

Strengths and Limitations

Reference

1. Nandini Debnath, Mohtada Sadrzadeh. Microfluidic Mimic for Colloid Membrane Filtration: A Review. Journal of the Indian Institute of Science volume. 2018.

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