Environmentally Sustainable Solvent-based Process Chemistry for Metals in Printed Circuit Boards

This chapter describes the development of several new processes relating to the fabrication, characterisation and recycling of printed circuit board (PCB) metal assemblies in alternative, sustainable solvent technologies based on an emergent class of liquids know as deep eutectic solvents (DES). It has been demonstrated that in many cases, the use of DES technologies can be disruptive to current process thinking and in principle can deliver benefits including increased efficiency,lower costs and better process control. These technologies offer the opportunity to incorporate new ideas into PCB fabrication and assembly that facilitate downstream, end-of-life recovery and separation consistent with a circular economy model. Current PCB manufacturing is carried out using many complex metal deposition processes involving aqueous solutions of toxic metal salts, strong inorganic acids, precious and expensive noble metals, and requires careful process control and monitoring. As a result, these processes are often costly to operate and inefficient. DES-based technologies can: (1) improve the economic and efficient use of essential metals; (2) reduce or eliminate use of precious and expensive metals; (3) reduce the use of complex and difficult to maintain process chemistry; (4) reduce reliance on toxic and noxious materials; and (5) improve recovery, recycling and reuse of PCB metals

Spectroelectrochemical responses of thin-film conducting copolymers prepared electrochemically from mixtures of 3,4- ethylenedioxythiophene and 2,2’-bithiophene

Here we have studied the electrocopolymerisation of binary mixtures of functionalised thiophenes in varying compositions and determined independently for each copolymer the 15 spectroelectrochemical responses and the composition of the material using x-ray photoelectron spectroscopy. We have observed strong correlations between the composition of the copolymer material and the composition of the binary solution from which the polymer was grown. In addition, we have shown that the spectroelectrochemical properties of the copolymers indicate the presence of random copolymer material where the λMax values of the neutral, undoped, polymer 20 scales with composition but also suggest that there may be small amounts of block copolymer or phase-separated mixtures of the homopolymer components

Quantitative, InSitu Visualization of Metal-Ion Dissolution and Transport Using ¹H Magnetic Resonance Imaging

Quantitative mapping of metal ions freely diffusing in solution is important across a diverse range of disciplines and is particularly significant for dissolution processes in batteries, metal corrosion, and electroplating/polishing of manufactured components. However, most current techniques are invasive, requiring sample extraction, insertion of an electrode, application of an electric potential or the inclusion of a molecular sensor. Thus, there is a need for techniques to visualize the distribution of metal ions non‐invasively, in situ, quantitatively, in three dimensions (3D) and in real time. Here we have used (1)H magnetic resonance imaging (MRI) to make quantitative 3D maps showing evolution of the distribution of Cu(2+) ions, not directly visible by MRI, during the electrodissolution of copper, with high sensitivity and spatial resolution. The images are sensitive to the speciation of copper, the depletion of dissolved O(2) in the electrolyte and show the dissolution of Cu(2+) ions is not uniform across the anode

Habitat Characteristics of Bracken-Covered Areas Intended for Afforestation in Ličko Sredogorje

Background and Purpose: Forest cultures in continental part of Croatia are mainly based on bracken-covered areas and moors on deserted agriculture soils and pastures. Successful afforestation i.e. establishment of forest cultures depends among other things on the understanding of habitats and ecology of forest trees. The choice of best species of forest trees for afforestation needs to be based on the research in soil and climate characteristics of target habitats. The aims of this research were to show mesoclimatic characteristics of Ličko sredogorje and microclimatic and pedological characteristics of Ličko polje. Also, based on habitat characteristics and ecology of forest trees, the aim was to determine species of forest trees suitable for afforestation of bracken-covered areas. Materials and Methods: Climate, microclimate, pedological and plant nutrition researches were done at the area of Lika highlands. Climate analysis was done according to air temperatures, amount of precipitation, relative air humidity and other climate elements and appearances. Composite soil samples were taken from the depth of 0-30 cm in order to determine plant nutrition potential. Samples were prepared for further analysis in the laboratory. Results: The highest average annual air temperature of 9.6 °C was found at weather station Gračac and the lowest at Korenica station (8.1 °C). Average amount of precipitation for this region was around 1500 mm. Monthly rain factors were ranging from arid to perhumid. Considering thermal character of the climate, the area has moderately warm climate. Average volumetric soil humidity is 14.2 %. Soil has strong acid reaction, is very humus, good to richly supplied with total nitrogen, content of physiologically active phosphorus and potassium is low, and C/N ration normal. Conclusions: According to habitat characteristics in the area of Ličko sredogorje and ecological demands of forest tree species, forest cultures of Common birch (Betula pendula Roth.), Common spruce (Picea abies Karst.), Eastern white pine (Pinus strubus L.), Black pine (Pinus nigra subsp. austriaca Asch i Gr.), Common pine (Pinus sylvestris L.) and European trembling aspen (Populus tremula L.) can be established