Search

The Mediterranean region faces significant challenges concerning food security and safety. A major cause of this problem is the disposal of inadequately treated livestock waste in soil and water resources with adverse environmental implications1,2. Currently, the most common manure management practice is solid-liquid separation, while a small percentage of these waste is anaerobically digested (6.4% in EU 273 ). Therefore, in order to alleviate this problem, technologies and processes that turn hazardous waste into valuable and profitable resources, are urgently needed. CUT participated in the Interreg MED project RE-LIVE WASTE, where the existing struvite crystallization reactor (SCR) from a previously built pilot that anaerobically treated livestock waste, was upgraded and re-operated to convert livestock waste into highvalue commercial organo-mineral fertilizers (struvite). A series of pilot-scale struvite crystallization experiments was first conducted utilizing ultra-filtration (UF) permeate as starting material. Pig slurry or mixed livestock were anaerobically treated, with the digestate effluent filtered through filter bags and UF ceramic membranes prior to struvite precipitation in the 250-L SCR. The produced struvite precipitates were analysed for their quality characteristics by X-Ray Diffraction (XRD), Scanning Electron Microscopy coupled with Energy Dispersive X-ray analysis (SEM-EDX), and X-Ray Fluorescence (XRF), spectroscopic techniques. Several analytical techniques for fertilizers were used for the determination of parameters such as polycyclic aromatic hydrocarbons (PAHs), and hexavalent chromium (Cr6+). Struvite precipitates from UF permeate mixed waste and pig slurry had high purity, more than 90% w/w, based on XRD analysis using Reference Intensity Ratio method. Typical struvite structures such as orthorhombic were observed in SEM-EDX. The precipitates complied with the regulatory requirements for pathogens, carcinogens (PAHs, PCBs, and Cr6+), and heavy metals (XRF) (Regulation (EU) 2019/1009). Overall, results from our pilot-scale process unveiled that nutrient recovery from recalcitrant livestock waste is feasible, producing a highvalue solid organo-mineral fertilizer.

A coupled Microbial Electrolysis Cell (MEC) – Anaerobic Granular Sludge (AGS) system was settled to investigate for the first time the ability of various carbon-based electrodes to enhance biodegradation of real bilge water (BW) and increase methane generation as an emerging technology for converting organic matter into value-added products. Results revealed that the performance of the three types of electrodes named carbon foam (CF), carbon cloth (CC) and three-dimensional graphene foam (3DG), was both time and organic load content dependent during the experimental cycles. Cumulative CH4 generation reached 235 mL in just 13 days after feeding the AGS with 50% of BW and application of 1.0 V at 3DG electrodes, followed by CC electrodes (148.3 mL). CF proved to be more resistant in higher BW concentration showing a sufficient performance of 1 month. However, in the third cycle, the performances of MECs containing 3DG and CC were higher compared to the CF and the control. Over the first cycle, the soluble Chemical Oxygen Demand (sCOD) removal was found to be around 70% to all MECs, and this value was around 10% higher than the control. Among the different Volatile Fatty Acids (VFAs), acetic acid was identified in the highest concentration in the first cycle, whereas propionic acid was detected in the second and third cycles. Microbial profile analysis showed that Methanobacterium and Desulfovibrio had substantially higher abundances in the cathodes than in the suspended anaerobic sludge. An X-ray diffraction (XRD) investigation of the used electrodes pointed out the formation of various crystalline compounds on their surface, which were different for the anode and cathode.

A coupled microbial cell (MEC) – anaerobic granular sludge system was settled to investigate the ability of different carbon modified electrodes to enhance biodegradation of undiluted bilge water (BW) and increase methane generation. MEC is an emerging technology for converting organic matter into value-added products such as methane. According to the results, 3D graphene found to be the most promising among the three tested materials. CH4 content reached 62% in just 10 days after feeding of the anaerobic granullar sludge with 50% of real undiluted bilge water and application of 1V. Regarding chemical oxygen demand (COD) removal values as high as 63% were observed. Among different Volatile Fatty Acids (VFAs) normally detected during anaerobic treatment, acetic acid was the most abundant.

The formation of different types of structural polymorphs of poly(3-hexyl-thiophene) (P3HT) affects the performance of organic photovoltaic (OPV) devices that use thermally annealed P3HT:PCBM[60] blend films as a photoactive layer. Here it is demonstrated that when densely packed and nondensely packed P3HT polymorphs coexist in the P3HT:PCBM[60] layer, nongeminate charge recombination is fast however, in a device nongeminate recombination is effectively overruled by efficient and fast charge carrier extraction. In stark contrast, when only a less densely packed P3HT polymorph is present in the blend, nongeminate charge recombination losses are less pronounced, and the charge carrier extraction efficiency is lower. The antagonistic nongeminate charge recombination and charge carrier extraction processes in these systems are monitored by time-delayed collection field (TDCF) and ultrafast transient absorption (TA) experiments. Furthermore, resonance Raman spectroscopy reveals that in the absence of the densely packed P3HT polymorph the energetic disorder present in the P3HT:PCBM[60] blend is higher. High-resolution atomic force microscopy imaging further identifies pronounced differences in the layer morphology when the polymorph distribution varies between unimodal and bimodal. These results indicate that less densely packed P3HT polymorphs increase disorder and impede charge collection, leading to a reduction of the device fill factor. 122 51 29141 29149

This article belongs to the Special Issue Catalysis for Energy Production Multifunctional materials for energy conversion and storage could act as a key solution for growing energy needs. In this study, we synthesized nanoflower-shaped iron-nickel sulfide (FeNiS) over a nickel foam (NF) substrate using a facile hydrothermal method. The FeNiS electrode showed a high catalytic performance with a low overpotential value of 246 mV for the oxygen evolution reaction (OER) to achieve a current density of 10 mA/cm2, while it required 208 mV at 10 mA/cm2 for the hydrogen evolution reaction (HER). The synthesized electrode exhibited a durable performance of up to 2000 cycles in stability and bending tests. The electrolyzer showed a lower cell potential requirement for a FeNiS-Pt/C system (1.54 V) compared to a standard benchmark IrO2-Pt/C system (1.56 V) to achieve a current density of 10 mA/cm2. Furthermore, the FeNiS electrode demonstrated promising charge storage capabilities with a high areal capacitance of 13.2 F/cm2. Our results suggest that FeNiS could be used for multifunctional energy applications such as energy generation (OER and HER) and storage (supercapacitor).

To contribute to solving global energy problems, a multifunctional CoFe2O4 spinel was synthesized and used as a catalyst for overall water splitting and as an electrode material for supercapacitors. The ultra-fast one-step electrodeposition of CoFe2O4 over conducting substrates provides an economic pathway to high-performance energy devices. Electrodeposited CoFe2O4 on Ni-foam showed a low overpotential of 270 mV and a Tafel slope of 31 mV/dec. The results indicated a higher conductivity for electrodeposited compared with dip-coated CoFe2O4 with enhanced device performance. Moreover, bending and chronoamperometry studies suggest excellent durability of the catalytic electrode for long-term use. The energy storage behavior of CoFe2O4 showed high specific capacitance of 768 F/g at a current density of 0.5 A/g and maintained about 80% retention after 10,000 cycles. These results demonstrate the competitiveness and multifunctional applicability of the CoFe2O4 spinel to be used for energy generation and storage devices.

Re-use of End-of-life tyre components into concrete is a viable solution to the environmental issue of tyre waste that can result in promising, high added value concrete applications. End-of-life tyre particles are added to conventional concrete by replacement of a percentage of its aggregate content, improving concrete deformability. The material is currently in the initial stages of research for structural applications, with weakness observed over the interfacial transition zone between the rubber and cement paste. This paper examines the potential of cement substitution by a combination of micro and nanoscale silica particles as well as the effect of rubber pre-treatment by coating with a Diabase quarry dust slurry for surface modification; aiming to refine the rubber/cement paste interface in rubberised concrete, thus improving its compressive strength and consequently structural performance. The effectiveness of cement substitution and rubber treatment methods is measured by comparison of the samples compressive strength at 7 and 28 days and detected in microscopic observations of hardened rubberised concrete samples. It is indicated the rubber pre coating method investigated is a promising procedure, proven to be effective in reducing the porosity at the rubber-cement paste interface and increasing the 28-day concrete compressive strength more than twice.

Nanoindentation is employed to investigate at the nanoscale the mechanical properties of multiply-interpenetrated N,N-dimethylacrylamide hydrogels cross-linked using N,N′-methylenebis(acrylamide). The main result from these measurements is the determination of the hardness of the materials, that is, their resistance to penetration by the nanoindenter, which increases with network multiplicity, arising from the increase in network compactness with multiplicity. In addition to hardness, the nanoindentation elastic modulus and the percentage of recoverable energy are also determined, and both are found to increase with network multiplicity as well. A general conclusion from this study is that nanoindentation is a facile and fast method for the characterization of a number of mechanical properties of hydrogels, with the important advantage of small amount of sample required for the measurements. 385 1

Significant efforts have been focused on the search of earth-abundant elements to solve growing energy issues and to provide bifunctional behavior for both hydrogen and oxygen evolution reaction. Mixed transition metals could provide promising synergistic electrochemical properties and serve as bi-catalyst for overall water splitting process. In this study, a needle grass array of nanostructured nickel cobalt sulfide (NiCo2S4) was synthesized using a hydrothermal process. The synthesized NiCo2S4 electrodes showed promising electrocatalytic activity with a low overpotential of 148 mV and 293 mV for hydrogen and oxygen evolution reactions, respectively. The electrolyzer cell consisting of two NiCo2S4 electrodes displayed excellent performance with high electrochemical stability and low overall cell potential of 1.61 V to achieve a current density of 10 mA/cm2. Our study suggests that mixed transition metal chalcogenides such as NiCo2S4 could be used as efficient and stable electrocatalyst for overall water splitting process. 354 306 312