Available Technologies and Materials for Waste Cooking Oil Recycling

Recently, the interest in converting waste cooking oils (WCOs) to raw materials has grown
exponentially. The driving force of such a trend is mainly represented by the increasing number of
WCO applications, combined with the definition, in many countries, of new regulations on waste
management. From an industrial perspective, the simple chemical composition of WCOs make
them suitable as valuable chemical building blocks, in fuel, materials, and lubricant productions.
The sustainability of such applications is sprightly related to proper recycling procedures. In this
context, the development of new recycling processes, as well as the optimization of the existing ones,
represents a priority for applied chemistry, chemical engineering, and material science. With the
aim of providing useful updates to the scientific community involved in vegetable oil processing,
the current available technologies for WCO recycling are herein reported, described, and discussed.
In detail, two main types of WCO treatments will be considered: chemical transformations, to exploit
the chemical functional groups present in the waste for the synthesis of added value products, and
physical treatments as extraction, filtration, and distillation procedures. The first part, regarding
chemical synthesis, will be connected mostly to the production of fuels. The second part, concerning
physical treatments, will focus on bio-lubricant production. Moreover, during the description of
filtering procedures, a special focus will be given to the development and applicability of new
materials and technologies for WCO treatments