Scalable fabrication of multifunctional NiCr plasma coatings for environmental remediation via oil-water separation and electrocatalytic dye degradation

The pressing need for efficient and sustainable oil-water separation systems arises from the widespread environmental and industrial challenges of oil spills, wastewater contamination, and petrochemical processing. Traditional separation methods often struggle to achieve effective separation under varying environmental conditions, especially in extreme pH, temperature, or complex mixtures. To address this, a superhydrophobic NiCr coating on stainless steel mesh was developed using the scalable plasma spray method, designed specifically for selective oil-water separation. The NiCr-coated mesh demonstrated a significant increase in hydrophobicity, achieving a water contact angle of 153.4° compared to the bare mesh’s 98.1°, which enabled efficient separation by selectively allowing only oil to permeate. Different kinds of oil/water mixtures of petrol, toluene, chloroform, hexane and silicone oil are efficiently separated. Thermal stability and durability tests confirmed the mesh's ability to maintain hydrophobicity across a range of temperatures, pH levels, and under mechanical stresses such as high-speed water jets. In addition to separation, the same NiCr coating was employed as an anode for the electrocatalytic degradation of Rhodamine B, demonstrating its multifunctionality. The multifunctional NiCr coating showcases strong potential for environmental remediation, serving as a scalable solution for both oil-water separation and electrocatalytic dye degradation under ambient conditions.