Optimizing mild surface cleaning methods: influence of water purity and pH.

Area of Science:

• Environmental Science
• Surface Chemistry
• Materials Science

Background:

• Growing environmental concerns drive research into eco-friendly detergents and washing methods.
• Purified water effectively cleans hydrophilic surfaces but struggles with hydrophobic ones, particularly for oil removal.

Purpose of the Study:

• To investigate olive oil removal from hydrophobic and hydrophilic surfaces using modified purified water.
• To evaluate the impact of water alkalinity, salt solutions, washing cycles, and temperature on cleaning efficiency.

Main Methods:

• Studied olive oil removal using varying water alkalinity (pH adjustment), salt concentrations, multiple washing cycles, and temperatures.
• Employed gravimetric analysis to quantify oil removal from different surface types.

Main Results:

• For hydrophobic surfaces, increasing purified water pH with minimal NaOH significantly improved oil removal.
• Hydrophilic surfaces showed near-complete oil removal with increased water alkalinity.
• Higher temperatures consistently enhanced the cleaning efficiency for both surface types.

Conclusions:

• pH-adjusted purified water is a promising eco-friendly alternative for effective oil removal.
• The mechanism involves fatty acid deprotonation, reduced interfacial tension, and enhanced roll-up.
• Future research should extend these findings to complex materials like textiles.