Stabilizing Triglyceride in Methanol Emulsions via a Magnetic Pickering Interfacial Catalyst for Efficient Transesterification under Static Conditions

Abstract

Pickering emulsion systems provide potential platforms for simultaneously intensifying and catalyzing transesterification between triglyceride and methanol under static conditions. However, realizing static transesterification with high biodiesel yield is still challenging due to low emulsion stability at the reaction temperature. Here, a series of magnetically recyclable Pickering interfacial catalysts (PICs) with similar surface affinities but different densities were constructed as stabilizers of a soybean oil/methanol emulsion. The variations in the emulsion volume fraction and droplet size were comparatively studied and analyzed from the viewpoint of droplet settling and catalyst particle shedding. It is found that, except for surface affinity, PIC density also plays a pivotal role in emulsion stability owing to the non-negligible effect of gravity on catalyst adsorption in triglyceride/methanol emulsion (especially at elevated temperature). By reducing the density, finely improving the lipophilicity, and optimizing the addition amount of PIC, the obtained soybean oil/methanol emulsion can remain stable for at least 12 h at 60 °C, enabling static transesterification with a high biodiesel yield of 95.6%. Moreover, the best performing PIC can be reused for at least 7 cycles. This efficient static transesterification system offers a green strategy for biodiesel production.

Multiresponsive Behavior of the Pickering Emulsifier and Its Application for Collecting Small Oil Droplets in Water

“…where ΔE was adsorption free energy, r was the particle dimension of P(DMAEMA-b-A-CD)/Fe 3 O 4 nanoparticles, γ ow was the interface tension, 55 water, it immediately dispersed. However, when dropped into toluene, the Pickering emulsion maintained its original shape.…”

“…Additionally, an excessively high surface charge on the nanoparticles was detrimental to the stability of the emulsion, leading to a slight decrease in interfacial activity. The stability of the Pickering emulsion was related to the contact angle of solid particles at the interface and the free energy of desorption (Δ E ), which could be expressed as Δ E = π r 2 γ o w false( 1 − | cos θ | false) 2 where Δ E was adsorption free energy, r was the particle dimension of P(DMAEMA- b -A-CD)/Fe 3 O 4 nanoparticles, γ ow was the interface tension, and θ was the three-phase contact angle of P(DMAEMA- b -A-CD)/Fe 3 O 4 nanoparticles. P(DMAEMA- b -A-CD)/Fe 3 O 4 nanoparticles had a high adsorption free energy Δ E = 9.5 × 10 6 k B T (Table S1) at pH = 10.…”

Energy Valorization of Olive Mill Waste Cake – Extraction of Vegetable Oil and Transesterification

“…The transesterification reaction represents one of the most important methods used to achieve this conversion and obtain an economically reliable and easy-to-implement biofuel. It is a process in which triglycerides are transformed in the presence of an alcohol (methanol or ethanol) and a catalyst into ester and glycerol (Zhang et al, 2021;Nikolić et al, 2021).…”