A Review On Grease Formulation Utilizing Waste Materials From Palm Oil Refineries And Other Industrial By-ProductsIf you are interested in products related to the research phase in this field, please contact for further inquiries.
In the face of escalating environmental concerns, the industrial sector is under increasing pressure to adopt sustainable practices. One critical area is lubrication, where traditional greases often rely on non-renewable and environmentally harmful base oils and thickeners. The transition towards sustainable lubrication is not only an ecological imperative but also an economic opportunity. By repurposing industrial waste into high-performance greases, we can mitigate pollution, conserve resources, and foster a circular economy. This article explores the innovative process of transforming waste cooking oil (WCO) and spent bleaching earth (SBE) into eco-friendly grease formulations.
Fig 1. Flow chart of the general overview for the grease formulation steps. (Hairunnaja M. A., et al., 2023) 
Base Oil Selection: Waste Cooking Oil
Waste cooking oil, despite its contaminated state, holds promise as a base oil for grease formulation. Its chemical properties, including viscosity and fatty acid content, make it a viable alternative to mineral oils. However, WCO must undergo rigorous treatment to remove impurities such as metal traces, organic molecules, and water content. Filtration and heating processes are employed to purify WCO, ensuring it meets the quality standards required for grease production.
Thickener Options: From Hazardous to Sustainable
Traditional thickeners like lithium hydroxide monohydrate and stearic acid, while effective, pose environmental and health risks. Lithium, for instance, is highly unstable and can ignite or explode if not handled properly. Spent bleaching earth, although initially classified as hazardous waste, can be transformed into a safe and effective thickener through proper treatment. The removal of residual oil and impurities renders SBE non-hazardous, allowing it to be used in grease formulations. Fumed silica, another promising thickener, offers excellent viscosity enhancement and thermal stability without the environmental risks associated with traditional thickeners.
Additives for Enhanced Performance
To further improve the performance of waste-based greases, additives like molybdenum disulfide (MoS2) are incorporated. MoS2, a dark grey to black powder, exhibits exceptional lubrication properties due to its layered structure and high specific area. It reduces friction and wear, enhancing the service life of machinery components. Graphite, when combined with MoS2, produces a synergistic effect, further boosting the grease's anti-wear and anti-friction properties.
Formulating Grease with Spent Bleaching Earth and WCO
A pioneering study demonstrated the feasibility of formulating grease using SBE and WCO. The researchers treated SBE to remove residual oil and impurities, rendering it safe for use as a thickener. WCO was purified through filtration and heating processes. The resulting grease exhibited excellent thermal stability and mechanical properties, comparable to commercial greases. This case study highlights the potential of repurposing industrial waste into high-performance lubricants.
Enhancing Grease Performance with Fumed Silica and MoS2
Another study focused on enhancing the performance of waste-based greases by incorporating fumed silica and MoS2. Fumed silica, with its high surface area and reactivity, improved the viscosity and stability of the grease. MoS2, as an additive, reduced friction and wear, extending the service life of machinery components. The combination of these innovative materials resulted in a grease that outperformed traditional lubricants in terms of thermal stability and tribological properties.
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Reference
This article is for research use only and cannot be used for any clinical purposes.
