High performance on the moisture reduction in waste oils by a bentonite-based adsorption process

Area of Science:

• Environmental Science
• Materials Science
• Chemical Engineering

Background:

• Waste oils, including waste cooking oil (WCO) and waste poultry fat (WPF), contain moisture that hinders their reuse in energy production.
• Reducing moisture content is crucial for improving the quality and economic viability of waste oil conversion into biofuels like biodiesel.

Purpose of the Study:

• To investigate the efficacy of a bentonite-based adsorption process for reducing moisture content in waste oils.
• To optimize the adsorption conditions for efficient moisture removal and assess the suitability of the treated oils for energy applications, specifically biodiesel production.

Main Methods:

• Characterization of waste oils (WCO, WPF) and bentonite clay adsorbent.
• Application of Response Surface Methodology (RSM) with a Full Factorial Experimental Design (FFED) to optimize adsorption parameters.
• Variation of adsorbent mass, oil acidity, and agitation speed, with fixed adsorption time, followed by kinetic and equilibrium adsorption tests.

Main Results:

• Optimized conditions (1.5 g adsorbent, 1 mgKOH/g oil acidity, 50 rpm agitation) achieved approximately 90% moisture removal.
• Adsorption equilibrium was reached within 5 hours.
• The BET isotherm model indicated a multilayer adsorption process with a high moisture adsorption capacity of ~200 mg water/g bentonite.

Conclusions:

• Bentonite clay is an effective adsorbent for significant moisture reduction in waste oils.
• The optimized adsorption process is suitable for preparing waste oils for economically viable biodiesel production.
• The findings support the reuse of waste oils as a sustainable feedstock for biofuel generation.