Identification of more benign cathode materials for the electrochemical reduction of levulinic acid to valeric acid

The electrochemical production of valeric acid from the renewable bio‐based feedstock levulinic acid has the potential to replace the oxo‐process which uses fossil‐based feedstock 1‐butylene. The electrochemical reduction of the ketone functionality in levulinic acid using lead or mercury cathodes is already known for over 100 years. However, large scale electrochemical production of valeric acid might be limited due to the toxicity of these materials. In this study, we identified three additional cathode materials, cadmium, indium and zinc, which selectively and efficiently produce valeric acid. Of these materials, indium and zinc are considered more benign. More specifically, at indium there is no formation of the side product γ‐valerolactone, thus resulting in the highest selectivity towards valeric acid. For the electrochemical reduction a reaction mechanism involving formation of an organometallic compound is proposed. Furthermore, a possible processing strategy is outlined to enable continuous electrochemical production of valeric acid on large scale

Continuous electrochemical oxidation of biomass derived 5-(hydroxymethyl)furfural into 2,5-furandicarboxylic acid

Abstract: A continuous electrochemical process with integrated product separation has been developed for production of 2,5-furandicarboxylic acid (FDCA) by oxidation of 5-(hydroxymethyl)furfural (HMF) in aqueous alkaline media on non-noble Ni/NiOOH foam electrodes at ambient conditions. Initially, voltammetry studies were performed in both, acid and alkaline media, on various catalyst materials: Au, Au3Pd2, Pt, PbO2, Ni/NiOOH and graphite. Preparative electrolysis was performed on Au, Au3Pd2, Pt, PbO2, Ni/NiOOH electrodes in a divided glass cell and Ni/NiOOH showed the best performance with an FDCA yield of ≈ 90% and a Faradaic efficiency of ≈ 80%. The electrolysis conditions were then optimized to industrially relevant conditions in a filter-press type flow reactor with Ni/NiOOH foam anode. HMF concentrations as high as 10 wt% were converted to FDCA at pH 12 in a buffer free 0.1 M Na2SO4 electrolyte with continuous addition of NaOH to maintain constant pH. An FDCA separation yield up to 95% was achieved via pH shift crystallization. The electrolysis and FDCA separation results were used for the design and construction of a bench-scale system where continuous FDCA production, including integrated product separation, was tested and reported in this work. This publication for the first time presents a continuous electrochemical FDCA production system with integrated product separation at industrially relevant product concentrations, 10 wt% HMF, and utilizing non-noble electrode materials. Graphical Abstract: [Figure not available: see fulltext.

Innovative financing (IF) of infrastructure projects in Ghana: conceptual and empirical observations

Traditional methods of financing have failed to resolve Ghana's infrastructure deficit. Innovative financing (IF) solutions are being encouraged to alleviate this, but presently IF knowledge is limited. This study provides an overview and maps the evolution of IF solutions to conceptually model their characteristics and application to major infrastructure projects, especially in the context of LDCs. An inductive methodology draws extensively on extant literature and published data from Ghanaian ministries, departments and agencies who procure infrastructure works. The study highlights how the IF concept stems from a plethora of public finance issues including reform of government service delivery, new tax tools, public–private partnerships and alternative financing arrangements and further how IF has been focused at educational, road, water infrastructure, housing and district assemblies. Through illumination of the Ghanaian IF concept, the study will be of utility to policy makers and international development agencies considering investment in the country, while its broader ramifications will help the search for alternative ways to finance infrastructure projects per se. It is concluded that further research would be beneficial in examining strategic IF issues, especially regarding the extent to which available tools and techniques are utilized in each of the four key IF phases (preparation, implementation, monitoring, evaluation)

Driving factors behind litter decomposition and nutrient release at temperate forest edges

Forest edges have become important features in landscapes worldwide. Edges are exposed to a different microclimate and higher atmospheric nitrogen (N) deposition compared to forest interiors. It is, however, unclear how microclimate and elevated N deposition affect nutrient cycling at forest edges. We studied litter decomposition and release of N, phosphorus (P), total cations (TC) and C/N ratios during 18 months via the litterbag technique along edge-to-interior transects in two oak (Quercus robur L.) and two pine (Pinus nigra ssp. laricio Maire and ssp. nigra Arnold) stands in Belgium. Furthermore, the roles of edge conditions (microclimate, atmospheric deposition, soil fauna and soil physicochemical conditions), litter quality and edge decomposer community were investigated as underlying driving factors for litter decomposition. Litter of edge and interior was interchanged (focusing on the influence of edge conditions and litter quality) and placed in open-top chamber (OTC), which create an edge (warmer) microclimate. As the decomposer macrofauna was more abundant at the edge than in the interior, the OTCs were used to isolate the effects of warming versus soil fauna. Oak litter at the edge lost 87 and 37% more mass than litter in the interior. We demonstrated an edge effect on litter decomposition and nutrient release, caused by an interplay of edge conditions (atmospheric deposition of N and TC, soil pH and C/N ratio), litter quality and soil fauna. Consequently, edge effects must be accounted for when quantifying ecosystem processes, such as litter decomposition and nutrient cycling in fragmented landscapes