Removal of pesticide residues from beeswax using a methanol extraction-based procedure: A pilot-scale study

Abstract

Abstract In the present study, a batch mode procedure has been developed to remove pesticides from beeswax coming from bee farms. The beeswax is treated by an Extraction Process with methanol at 65 °C followed by an Adequation Process with water at 70 °C. This procedure can reduce the beeswax contamination load by values of around 80% – 90% for the acaricides usually present in beeswax such as Coumaphos, Chlorfenvinphos, tau-Fluvalinate and Acrinathrin, at concentration ranges of 1800 – 2600 μ g/kg, 140 – 300 μ g/kg, 100 – 300 μ g/kg and 160 – 470 μ g/kg, respectively. This process is also able to eliminate other pesticides, such as Amitraz, which are typically present in beeswax samples at high concentrations. Similarly, it is efficient in removing further compounds such as Propiconazole, Bromopropylate, Chlorpyrifos, Cypermethrin, Diazinon and Fenamiphos, which are present at lesser quantities depending on their origin and surrounding pesticide treatment history. The procedure’s operating parameters were atmospheric pressure, a 20 °C – 70 °C temperature range and 200 rpm. Up to 80% of the methanol used in the extraction was recycled and the waste generated was easy to manage. The quality of the decontaminated beeswax obtained has similar properties to those of virgin beeswax and can be used to manufacture ecological hives or galenic formulations. Beeswax quantities of 1, 20 and 75 kg were treated to determine the optimal operating conditions that would make it possible to extend the process to the industrial scale. All the equipment utilized (e.g. agitated tanks, temperature control, centrifuges and distillation equipment) are basic tools commonly used in the chemical industry.