In-Depth Breakdown: How Ozone Catalytic Oxidation Demulsification + Ultra-Fine Nanobubble Flotation Enable CDOF to Achieve Over 99% Oil Removal

In the production chain of new-energy battery materials, wastewater treatment is becoming an increasingly critical step. Metallurgical and washing wastewater generated by ternary precursor, lithium-battery recycling, and nickel-cobalt-manganese smelting exhibits oil pollution with three major characteristics: "high concentration, multi-form, strong emulsification" — emulsified oil, dispersed oil and suspended solids coexist, oil content is high and water quality fluctuates greatly, with emulsified oil being especially stubborn.

Why do traditional processes fail? Fenton + flocculation-settling is unstable and easily re-colorizes, consumes large amounts of chemicals (cost ≥ 25 yuan/ton), produces high sludge (4 kg/t), and carries risks of wastewater re-colorization and gas leakage. Physical methods such as coalescence separation have limited removal efficiency against high-concentration emulsified oil and struggle to stably meet standards. SINOKLE's CDOF ozone catalytic oxidation flotation integrated technology uses the combination of "ozone catalytic oxidation demulsification + cyclonic flotation" to achieve over 99% oil removal and stable compliance. How strong is this system exactly? This article breaks it down from mechanism to data.

1. Dissect the difficulty first: why is emulsified oil "hard to chew"?

Oil in wastewater can be divided by form into two categories:

• Dispersed oil: oil droplets are relatively large with good floatability, separable by conventional flotation.

• Emulsified oil: under stirring, pumping and surfactant action, oil droplets are dispersed into micron-scale particles, stably suspended in water and wrapped in an interfacial film. This film, formed by the oriented arrangement of surfactant molecules, has strength and stability that prevent the droplets from coalescing or rising — conventional coalescence and flotation cannot break through it.

This is the root of why coalescence separation is "powerless" against high-concentration emulsified oil: it can intercept "the oil that floats up" but cannot break "the oil hidden in water wrapped in a film".

2. Dissect the solution: CDOF's three-step synergistic mechanism

Step 1: Ozone multi-catalytic oxidation — break the film. After the wastewater is conditioned by a water-quality modifier, it enters the CDOF integrated unit. The unit builds four catalytic paths — homogeneous catalysis, heterogeneous catalysis, hydrodynamic cavitation catalysis and pressurized catalysis — which work together to efficiently convert ozone into highly active hydroxyl radicals (·OH). ·OH is an extremely strong oxidant that attacks and destroys the interfacial film of emulsified oil at the molecular level, "liberating" the oil droplets from the emulsified state. The entire demulsification process is physical — it does not rely on chemical demulsifiers, only a trace amount of water-quality modifier, greatly reducing chemical consumption and secondary-pollution risk.

Step 2: Ultra-fine nanobubble flotation — capture. The dissolved-air release system produces ultra-fine nanobubbles with diameters below 10 μm. Compared with conventional bubbles, nanobubbles are smaller, have higher number density and larger specific surface area, markedly improving capture efficiency. The demulsified oil droplets are "captured" by the nanobubbles and rise to the surface with buoyancy, aggregating into a scum layer.

Step 3: Automatic slag discharge — wrap-up. The scum is discharged by an automatic slag-discharge system, and the effluent oil stably meets standards. The reaction runs fully enclosed and pressurized with a retention time of less than 15 minutes; equipped with an ozone-generation system, tail-gas destructor and clean-water backwash system, and DCS/PLC fully automatic control enabling unattended operation.

3. One comparison table to understand the generational gap

Item by item, CDOF's advantage is not in any single aspect but leads in all dimensions: demulsification changes from "chemical stacking" to "physical precision strike", effect changes from "unstable and easy re-colorization" to "colorless, odorless, no re-colorization", speed is 4–6× faster, cost drops to 1/3–1/2, sludge drops to 1/40, and safety and footprint improve comprehensively.

4. Case data: closing the loop from theory to evidence

Case 1: A new-energy battery-material manufacturer — sodium-sulfate solution oil-removal pilot. Influent oil 32.1 mg/L, COD 1215 mg/L, total phosphorus 11 mg/L; after 200 mg/L ozone dosing: oil dropped to 2.3 mg/L (92.8% removal), COD to 285 mg/L (76.5% removal), total phosphorus to 1.8 mg/L (83.6% removal). Notably, while removing oil, CDOF simultaneously degrades COD and total phosphorus, reflecting the comprehensive "one-machine, multi-effect" treatment value.

Case 2: Ammonium-sulfide / sodium-sulfate wastewater oil-removal test. Raw water oil ≤ 500 mg/L with 500 mg/L ozone: effluent oil ≤ 0.4 mg/L (99.9% removal); raw water oil ≤ 100 mg/L with 100 mg/L ozone: effluent oil ≤ 14.8 mg/L. The two cases cover the two typical conditions of "medium concentration + multi-indicator synergy" and "high concentration + ultra-high removal" respectively, verifying CDOF's broad adaptability to oil wastewater of different concentrations in the new-energy industry.

5. Summary

CDOF's over-99% oil removal is not the credit of a single step, but the result of system synergy among "ozone catalytic oxidation demulsification + ultra-fine nanobubble flotation + automatic slag discharge": the demulsification step solves the mechanistic problem of "oil cannot be broken", the flotation step solves the separation problem of "oil not cleaned", and the slag-discharge step solves the operational problem of "slag not cleared", further guaranteed by fully enclosed, fully automatic and skid-mounted design for engineering deployment. For new-energy enterprises, this is an oil-removal solution that withstands scrutiny from mechanism to data.