Application 1030 Rotating bed reactor filled with adsorbent for decolorization

Viscous solutions decolourized using a rotating bed reactor and a stirred tank reactor

Decolorization, pesticide remediation, catalysis, and many other applications involve dealing with viscous liquid that needs to be modified in some way. The rotating bed reactor presents an efficient way to treat viscous liquids, without the challenges of conventional reactors.

The treatment of viscous liquids is widespread in the manufacturing of liquid products. Some examples are

  • Pesticide remediation in natural oils
  • Decolorization of cannabis or hemp extract
  • Heterogeneous biocatalysis on feedstocks rich in free fatty acids (FFA)

Common for these applications are the use of a solid-phase material (adsorbent or catalyst) to achieve the desired change in product quality. The high viscosities can make the deployment of that solid-phase challenging. Passing the product through a fixed bed reactor is associated with a high backpressure and tedious loading of the solids, while a batch reactor might rapidly destroy the solids and require slow filtration after the process.

In this application note, a rotating bed reactor (RBR) was compared to a stirred tank reactor (STR), also known as a batch reactor, for the decolorization of a highly viscous solution of a dye. The RBR removed 10 times the amount of dye in just over 40 % of the time, compared to the STR. This comparison underlines the efficient mixing and effective mass transfer achieved by the SpinChem® RBR. It also opens the door to a broad spectrum of applications for which this technology is superior:

  • Enzymatic refinement of viscous feedstocks
  • Pesticide remediation in natural oils and extracts
  • Decolorization of products in pharma, food & beverage, and flavours & fragrances

Get started with the rotating bed reactor technology today.


Conditions: Glycerol (80%, wt) was mixed with dH2O and Allura red (20 mg/L). The mixture was kept at a temperature of 10°C to achieve a viscosity of around 0.116 · 10¯³ m²/s. A SpinChem® RBR S3 was filled with 41.6 g macroporous strong base anion exchange resin (Purolite® A500 MB Plus) and spun in 1 L of the mixture at 400 rpm. For the STR experiment, 41.6 g of the same ion exchange resin was suspended in 1 L of the viscous dye solution, and stirred by means of an impeller at 400 rpm. Samples for absorbance measurements were taken over time and analysed using UV-Vis spectroscopy.

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