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This study points out a new perspective on CO2 sequestration and H2 gas generation in a system of either zero-valent iron (Fe0) or scrap iron along with NaHCO3 and citric acid. Under a high bicarbonate environment, micro-size Fe0 (5–40 g/L) is oxidized at mild anaerobic conditions, generating hydrogen gas with a production rate in the range of 0.09–0.55 g(H2)/kg(Fe0)·h. At the same conditions without bicarbonate, the generation of H2 was negligible. At the end of the reaction, the pH was alkaline so it can be used to absorb CO2. Carbonate ions create a passivation layer on the Fe0 surface, called siderite (FeCO3), that entrapped Fe0 and hindered H2 production. By comparing citric, oxalic, and ascorbic acids for their ability to remove the siderite layer, citric acid was found to be the most effective. In a system of scrap iron-NaHCO3/citric acid, for seven consecutive cycles, it was found that by replacing the media solution with a new media after the end of each cycle and flushing with CO2 in the beginning of each cycle resulted in higher than 85 vol% H2 after one day of exposure and higher than 94 vol% H2 at the end of each cycle.

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.

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).

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.

Wear and corrosion have been identified as two of the main forms of metallic implant failure mechanisms [1-3]. The objective of this work was to improve the protective and tribomechanical characteristics of metallic surfaces used for medical implants. Towards this end, hydrogenated amorphous carbon (a-C:H) nanofilms have been deposited on Stainless Steel (SS), Titanium (Ti) and Niobium (Nb) metal plates using Plasma Enhanced Chemical Vapor Deposition (PECVD). The nanomechanical and nanotribological characteristics of the bare and a-C:H coated metallic surfaces have been quantified through nanoindentation and nanoscratch testing, respectively. The density and thickness of the a-C:H films have been probed using X-ray reflectivity (XRR) whereas the morphological characteristics of the metallic surfaces before and after a-C:H deposition have been studied using atomic force microscopy (AFM). Furthermore, the residual imprints through nanoscratch testing have been investigated using scanning electron microscopy (SEM). In summary, it is observed that the a-C:H films improve the tribomechanical properties of the metallic surfaces by reducing their friction coefficient and improving their resistance to plastic deformation and wear.

© 2005, CISM, Udine. Is it possible to break down natural porous material systems down to a scale where materials no longer change from one material to another, and upscale (‘nanoengineer’) the behavior from the nanoscale to the macroscale of engineering applications? — This is the challenging question we address in these lecture notes through a review of tools and methods of experimental microporomechanics. The combination of advanced experimental indentation techniques and microporomechanics theory provides a unique opportunity to understand and assess nanoproperties and microstructure, as a new basis for the engineering prediction of macroscopic poromechanical properties of natural composites. This is illustrated for cement-based materials and shales.

OBJECTIVE - The purpose of this study was to evaluate the effectiveness of a temperature monitoring instrument to reduce the incidence of foot ulcers in individuals with diabetes who have a high risk for lower extremity complications. RESEARCH DESIGN AND METHODS - In this physician-blinded, randomized, 15-month, multicenter trial, 173 subjects with a previous history of diabetic foot ulceration were assigned to standard therapy, structured foot examination, or enhanced therapy groups. Each group received therapeutic footwear, diabetic foot education, and regular foot care. Subjects in the structured foot examination group performed a structured foot inspection daily and recorded their findings in a logbook. If standard therapy or structured foot examinations identified any foot abnormalities, subjects were instructed to contact the study nurse immediately. Subjects in the enhanced therapy group used an infrared skin thermometer to measure temperatures on six foot sites each day. Temperature differences >4°F (>2.2°C) between left and right corresponding sites triggered patients to contact the study nurse and reduce activity until temperatures normalized. RESULTS - The enhanced therapy group had fewer foot ulcers than the standard therapy and structured foot examination groups (enhanced therapy 8.5 vs. standard therapy 29.3%, P = 0.0046 and enhanced therapy vs. structured foot examination 30.4%, P = 0.0029). Patients in the standard therapy and structured foot examination groups were 4.37 and 4.71 times more likely to develop ulcers than patients in the enhanced therapy group. CONCLUSIONS - Infrared temperature home monitoring, in serving as an "early warning sign," appears to be a simple and useful adjunct in the prevention of diabetic foot ulcerations.