Maksym Tatariants

Characterization of waste printed circuit boards recycled using a dissolution approach and ultrasonic treatment at low temperatures

Recently, the separation of waste printed circuit boards (WPCBs) using organic solvents has become more prevalent because it is an environmentally friendly and efficient technique. However, the relatively high temperatures (∼135 °C) used during the separation process lead to higher energy consumption, faster solvent degradation, and possibly higher emissions of toxic fumes. This work aims to develop a new approach to separate all layers of WPCBs at lower temperatures to avoid the above-mentioned drawbacks. Di-methyl formamide (DMF) was used in the present technique as an organic solvent, while ultrasonic treatment was applied in order to accelerate the breakage of the internal van der Waals bonds of brominated epoxy resin (BER), thus decreasing the separation time. The experiments were conducted on five WPCB samples with the same surface area of 100 mm2, cut from five different WPCB models. The experiments were carried out at 25 °C (used as a reference), 50 °C, and 75 °C to study the effect of heating rate on the separation time and on the concentration of the BER dissolved in DMF. Ultraviolet-visible spectroscopy, metallographic microscope, and SEM-EDS were used to examine the recovered BER and fiberglass structure as well as the main metal compositions of each sample, respectively. The results showed that separation time and concentration of BER strongly depended on the WPCB models. In addition, the dissolution process at 50 °C resulted in the concentration of BER close to 25 °C for most of the models, while the concentration was lowest at 75 °C. At the same time, the trend in separation time was exactly opposite, with 75 °C resulting in the fastest separation time and 25 °C in the slowest. This facile approach appears promising for its potential applications in WPCB recycling and could be applied on an industrial scale.

Sustainable approach to recycling of multilayer flexible packaging using switchable hydrophilicity solvents

Multilayer Flexible Packaging Waste (MFPW) represents the largest fraction of packaging waste and is mainly composed of multiple plastic films laminated with Al foil. In the EU, mechanical and chemical recycling technologies are usually used to separate polymeric fractions from Al; however, these recycling practices have inherent crucial restrictions related to the recycling rate ( 99% while making the reprocessing of extracted polymers much simpler. Dissolved plastic materials could easily be recovered in the form of solid residues without heating through saturation of an adhesive polymer/SHS solution by CO2 under cooling, thus changing the hydrophilicity of the solvent and converting it into a polar water-miscible form. Although the experiments were conducted on the lab-scale on six different types of MFPW, selected depending on the most active packaging technologies in the EU (as used for potato chips, chocolate, bakery goods, ground coffee, ice cream, and biscuits), the authors took into account the possibility of technology implementation at the industrial scale through designing a technology layout for the developed approach (based on the sequence of treatment processes and the obtained results). Metallographic microscopy, SEM-EDS, FTIR, and TGA were used to examine the materials recovered from each MFPW type as well as the changes in the SHS solvent. Lastly, the CO2-equivalent emissions and economic performance of the developed technology were evaluated.