Try a mixture of 0.5 % v/v acetic acid and DI water( 5.5 -6.5). This will preserve both the CAD suspension and reduce the viscosity. Use can use ratio 1:3, so as to also enhance the separation. Usually, 8000 - 10k in 10 mins or a little higher. This will increase the clarity and will be okay depending on the centrifuge.. Collect the supernatant and move on with your dialysis.

Emmanuel Aduloju' answer is excellent.

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Here are distinct answer regarding the purification of **Carbon Quantum Dots (CQDs)**:

### **1. Centrifugation-Based Purification**

For CQDs synthesized with **chitosan in acetic acid**, a **0.5% v/v acetic acid and deionized (DI) water** mixture is recommended to maintain suspension stability and reduce viscosity. A **1:3 CQD suspension-to-solvent ratio** enhances separation, while a **centrifugation speed of 8000–10,000 rpm for 10 minutes** effectively isolates impurities. After centrifugation, collect the **supernatant** and proceed with dialysis to remove residual small molecules.

### **2. Advanced Purification Techniques**

Beyond centrifugation and dialysis, **ultrafiltration** using **PVC-PVA@Chitosan quantum dot membranes** can further refine CQDs. **Size-exclusion chromatography** or **ion-exchange chromatography** separates CQDs based on molecular weight or charge. **Solvent-based extraction** helps eliminate excess chitosan or acetic acid, while **controlled hydrothermal treatment** enhances purity and optical properties. Good luck

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