Search results for "DIALYSIS"

Modeling and Analysis of a New Process for Pyruvate Production

2005

Early process development is crucial for the economic and environmental performance of a final production process. A new process for the production of pyruvate is presented as a case study to show how process modeling and an analysis of the results regarding economic and environmental aspects improves the understanding of the process, its cost structure, and its environmental impact. It also enables the quantification of process improvements and the comparison of alternative designs. The model of the pyruvate production shows how strain and fermentation improvements propagate through the process and affect its economic and environmental performance. The comparison of two alternative purific…

Sleep Apnea and the Kidney

2020

Abstract Purpose of Review There are some uncertainties about the interactions between obstructive sleep apnea (OSA) and chronic kidney disease (CKD). We critically reviewed recent studies on this topic with a focus on experimental and clinical evidence of bidirectional influences between OSA and CKD, as well as the effects of treatment of either disease. Recent Findings Experimental intermittent hypoxia endangers the kidneys, possibly through activation of inflammatory pathways and increased blood pressure. In humans, severe OSA can independently decrease kidney function. Treatment of OSA by CPAP tends to blunt kidney function decline over time, although its effect may vary. OSA may increa…

SELECTION OF REDOX SYSTEMS FOR REVERSE ELECTRODIALYSIS PROCESSES

2012

In reverse electrodialysis (RED) processes, electrical energy is directly extracted from chemical potential gradients arising from salinity differences, especially from sea and river water. In RED there are at least four complementary elements: (1) electrodes, where electron transfer reactions occur to allow the transformation of the charge carrier from ion to electron; (2) ion selective exchange membranes, which allow the selective transport of ions; (3) solvents, which make a continuum for ion transport; (4) electrolytes, i.e. the current carriers between cathode and anode. Studies on RED processes were mainly focused on membranes but also on several other aspects including electrolyte co…

Investigation of electrode material - redox couple systems for reverse electrodialysis processes

2012

Towards the simultaneous generation of electric energy and the abatement of organic pollutants by reverse electrodialysis processes

2012

In reverse electrodialysis (RED) processes, electrical energy is directly extracted from chemical potential gradients arising from salinity differences, especially from sea and river water [1]. In RED there are at least four complementary elements: (1) electrodes, where electron transfer reactions occur to allow the transformation of the charge carrier from ion to electron; (2) ion selective exchange membranes, which allow the selective transport of ions; (3) solvents, which make a continuum for ion transport; (4) electrolytes, i.e. the current carriers between cathode and anode. The redox process is usually chosen in order to limit the energetic losses, the cost of redox specie and electro…

REVERSE ELECTRODIALYSIS PROCESSES FOR THE PRODUCTION OF CHEMICALS AND THE TREATMENT OF CONTAMINATED WASTEWATER

ABATEMENT OF POLLUTANTS IN AQUEOUS SOLUTIONS BY REVERSE ELECTRODIALYSIS PROCESSES

2013

Electrochemistry-based technologies are very promising methods for treating wastewaters containing organic and inorganic pollutants that are either resistant to biological processes or toxic for microorganisms [1]. On the other hand, in the reverse electrodialysis (RED), the electrical energy is directly extracted from chemical potential gradients arising from salinity differences [2], especially between brine solution and sea water. RED can be potentially used for the simultaneous generation of electrical energy and the treatment of waters contaminated by recalcitrant pollutants. The advantages of using the RED process for such dual purpose are: the utilization of a green reagent such as t…

Investigation of electrode material – redox couple systems for reverse electrodialysis processes. Part II: Experiments in a stack with 10–50 cell pai…

2013

Abstract The performances of reverse electrodialysis depend on several factors, including the nature of the electrode material and of the redox processes adopted to make possible the conversion between chemical potential and electric power. In this paper the possible utilization of various redox processes (reduction/oxidation of iron species, oxidation and reduction of water, oxidation of chlorine and reduction of water) was studied in a stack equipped with 10–50 cell pairs and by focused electrolyses in a three compartment cell. The effect of selected redox processes on power density output and eventual contamination of saline solutions flowing in the stack was evaluated in detail. The eff…

Oral health status in patients with moderate-severe and terminal renal failure.

2007

Aims. To evaluate the oral health status of patients with moderate-severe chronic renal failure (CRF) and with terminal renal failure (TRF). Design. The study group was formed of 50 patients: 22 (44%) with moderate-severe CRF and 28 (56%) with TRF included in a haemodialysis programme. The controls (n=64) presented similar characteristics with regard to sex, age, weight and educational level. A single dentist performed an intraoral examination on all the subjects, gathering information on: number of decayed, missing or filled teeth; supragingival plaque accumulation; calculus deposits; periodontal pockets in the Ramfjord teeth; and loss of insertion. Results. No significant differences were…

Coupling electrodialysis desalination with photovoltaic and wind energy systems for energy storage: Dynamic simulations and control strategy

2020

Abstract The presence of desalination systems in polygeneration facilities is usually limited by important difficulties in operating under non-stationary regimes typical of renewable energy sources. Reverse osmosis, namely the most common desalination technology, is characterised by slow dynamics that rarely adapts to the power fluctuations of renewables. Therefore, the possibility of using electrodialysis coupled with a hybrid photovoltaic/wind energy source was investigated in this work. In particular, the combination of photovoltaic and wind energy is very attractive in order to achieve a more stable energy production, while electrodialysis is claimed to be a more flexible process compar…