Regeneration of Colloidal Palladium Activation Solution

Introduction

The colloidal palladium activation solution is a colloidal solution with atomic palladium as the colloidal core, and its active center is composed of a disordered Pd-Sn alloy system. The smaller the size of the palladium particles, the higher the catalytic activity and the better the stability. The biggest feature of colloidal palladium activation solution is that sensitization and activation are concentrated in the dipping process of one solution and completed at the same time.

Fig.1 Schematic diagram of the microstructure and formation mechanism of colloidal palladium.^[1]

Our Solutions

Our regeneration services include but are not limited to the following:

Colloidal Activator Maintenance

The maintenance focus of colloidal palladium activation solution is to prevent Sn(II) from being oxidized while maintaining a certain acidity. Specifically include:

1. Try to avoid bringing oxidizing substances such as Cr⁶⁺, Fe³⁺ plasma into the solution. The stripped parts should be cleaned as much as possible and then activated.

2. Try to avoid bringing too much water and alkaline substances into the solution.

3. Fill the activation solution as much as possible, and store it in an opaque container.

Waste colloidal activation solution regeneration

• Determination of palladium content in waste colloidal palladium activation solution

We used an inductively coupled plasma spectrometer (ICP-AES) and a potassium iodide spectrophotometer to measure the palladium content in the spent activation solution in preparation for the palladium recovery step.

• Pretreatment of waste activation solution

We first used the thiocyanate copper precipitation method to remove the copper in the waste colloidal palladium activation solution, and then carried out oxidation and gel breaking treatment on the activation solution after copper removal.

• Recovery of palladium & regeneration of activation solution

Our recycling processes include methods such as direct leaching, precipitation, liquid membrane extraction and ion exchange membrane electrolysis. Then use the recovered palladium chloride to reconstitute the activation solution.

References

1. Huang S , et al. Microstructure characterization and formation mechanism of colloid palladium for activation treatment on the surface of PPTA fibers. Applied Surface Science. 2020, 516(3):146134.
2. Yangfu Zheng, et al. Maintenance and regeneration of colloid activation solution. Plating & Finishing.1991.
3. Songye Qin. Recycling of waste colloidal palladium activation solution [D]. Jiangsu Institute of Technology. 2021.

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