Vincenzo Piemonte

Bioplastics and Petroleum-based Plastics: Strengths and Weaknesses

Abstract The application of biomass, such as starch, cellulose, wood, and sugar, used to substitute fossil resources for the production of plastics, is a widely accepted strategy towards sustainable development. In fact, this way a significant reduction of non renewable energy consumption and carbon dioxide emission is accomplished. In recent years, several typologies of bioplastics were introduced and the most important are those based on cellulosic esters, starch derivatives, polyhydroxybutyrate, polylactic acid, and polycaprolactone. Nowadays, the most important tool to evaluate the environmental impact of a (bio)plastic is the life cycle assessment that determines the overall impact of a plastic on the environment by defining and analyzing several impact categories index like the global warming; the human toxicity; the abiotic depletion; the eutrophication; the acidification; and many others directly related to the production, utilization, and disposal of the considered plastics. The aim of this work is to present a comparison between bioplastics and conventional plastics through the use of the “Life Cycle Assessment” methodology. In particular, the life cycle assessments Cradle to Grave of shoppers made from Mater-Bi (starch-based plastic) an polyethylene were reported and compared as a case study in order to highlight the strengths and weaknesses of the bioplastics and the conventional plastics.

Predictive criteria for the outcome of patients with acute liver failure treated with the albumin dialysis molecular adsorbent recirculating system.

The aim of this study was to evaluate the improvement of prognostic parameters after treatment with the molecular adsorbent recirculating system (MARS) in patients with fulminant hepatitis (FH). The parameters conducive to a positive prognosis include: Glasgow Coma Scale (GCS) score ≥11, intracranial pressure (ICP) <15 mm Hg or an improvement of the systolic peak flow of 25–32 cm/s via Doppler ultrasound in the middle cerebral artery, lactate level <3 mmol/L, tumor necrosis factor‐α <20 pg/mL, interleukin (IL)‐6 <30 pg/mL, and a change in hemodynamic instability from hyperkinetic to normal kinetic conditions, and so define the timing (and indeed the necessity) of a liver transplant (LTx). From 1999 to 2008 we treated 45 patients with FH with MARS in the intensive care unit of our institution. We analyzed all the parameters that were statistically significant using univariate analysis and considered the patients to be candidates for inclusion in a multivariate logistic regression analysis. Thirty‐six patients survived: 21 were bridged to liver transplant (the BLT group) and 15 continued the extracorporeal method until native liver recovery (the NLR group) with a positive resolution of the clinical condition. Nine patients died before transplantation due to multi‐organ failure. We stratified the entire population into three different groups according to six risk factors (the percentage reduction of lactate, IL‐6 and ICP, systemic vascular resistance index values, GCS <9, and the number of MARS treatments): group A (0–2 risk factors), group B (3–4 risk factors), and group C (5–6 risk factors). Analyzing the prevalence of these parameters, we noted that group A perfectly corresponded to the NLR group, group B corresponded to the BLT group, and group C was composed of patients from the non‐survival group; thus, we were able to select the patients who could undergo a LTx using the predictive criteria. For patients with an improvement of neurological status, cytokines, lactate, and hemodynamic parameters, LTx was no longer necessary and their treatment continued with MARS and standard medical therapy.

Cytokine Level Modifications: Molecular Adsorbent Recirculating System Versus Standard Medical Therapy

INTRODUCTION Acute-on-chronic liver failure (ACLF) is a systemic inflammatory reaction, which is characterized by a predominantly proinflammatory cytokine profile, causing the transition from stable cirrhosis to ACLF. The aim of the present study was to evaluate the changes in several cytokines associated with inflammatory liver disease and liver regeneration among 15 ACLF patients treated with the Molecular Adsorbent Recirculating System (MARS) compared with 15 patients treated with standard medical therapy (SMT). The subjects showed various disease etiologies but similar values for Model End-stage Liver Disease scores. METHODS In the MARS group, 15 (10 male and 5 female) patients were treated with MARS (Gambro). The number of MARS applications was nine; the length of applications was 8 hours. In the SMT group; 15 (10 male and 5 female) patients were treated with SMT. The patients were monitored for 30 days from inclusion with a survival follow-up at 3 months. Statistical results were calculated with SPSS14.0 (SPSS Inc, Chicago, Ill). A P < .07 was considered significant. RESULTS In the MARS group, we observed significant changes in the levels of Interleukin (IL)-6, IL-1, IL-10, and tumor necrosis factor (TNF)-alpha in association with improved hepatocyte growth factor. Patient survival at 3 months was 60%. The SMT group showed only a significant change in TNF-alpha (P = .03). Patient survival at 3 months was 30%. CONCLUSION The MARS liver support device corrected pathophysiologies of ALF and may be used to enhance spontaneous recovery or as a bridge to transplantation.

Two-phase reactors applied to the removal of substituted phenols: comparison between liquid-liquid and liquid-solid systems

In this paper, a comparison is provided between liquid-liquid and liquid-solid partitioning systems applied to the removal of high concentrations of 4-nitrophenol. The target compound is a typical representative of substituted phenols found in many industrial effluents while the biomass was a mixed culture operating as a conventional Sequencing Batch Reactor and acclimatized to 4-nitrophenol as the sole carbon source. Both two-phase systems showed enhanced performance relative to the conventional single phase bioreactor and may be suitable for industrial application. The best results were obtained with the polymer Hytrel which is characterized by higher partition capability in comparison to the immiscible liquid solvent (2-undecanone) and to the polymer Tone™. A model of the two systems was formulated and applied to evaluate the relative magnitudes of the reaction, mass transfer and diffusion characteristic times. Kinetic parameters for the Haldane equation, diffusivity and mass transfer coefficients have been evaluated by data fitting of batch tests for liquid-liquid and liquid-solid two phase systems. Finally, preliminary results showed the feasibility of polymer regeneration to facilitate polymer reuse by an extended contact time with the biomass.

A Triethylene Glycol–Water System: A Study of the TEG Regeneration Processes in Natural Gas Dehydration Plants

Abstract Natural gas pipeline transportation requires very low water content in the gas stream in order to avoid condensation or hydrate formation. To reach this goal, when triethylene glycol is used to dehydrate natural gas, after the absorption step, triethylene glycol must be regenerated to levels substantially above 98.5–99.0% by weight available from atmospheric distillation of glycol-water mixtures. In order to regenerate triethylene glycol to higher purity levels, some of the methods used require a stripping gas, a solvent, or to perform the distillation under vacuum. Another method to perform a further dehydration of triethylene glycol is the use of a water exhauster, known as Coldfinger, where the vapor in equilibrium with the liquid to be dehydrated is continuously condensed and removed. In the first part of this work, measurements of boiling temperatures are reported for binary mixtures of triethylene glycol and water at pressures of 50, 100, 200, and 400 mmHg. The experimental data obtained were correlated by employing the NRTL model, with temperature-dependent parameters, to express activities in the liquid phase. The fitted NRTL parameters were then used in the Hysys process simulator to perform a process simulation of a natural gas dehydration plant, provided both with a Coldfinger water exhauster and a conventional stripping column for triethylene glycol regeneration.

Reverse osmosis membranes for treatment of produced water: a process analysis

AbstractThe purpose of this paper was to develop and present a process suitable for the purification of the so-called produced waters, a by-product of crude oil extraction, by devising a treatment train aimed at industrial and agricultural water reuse. If compared to municipal wastewaters, produced waters have a very high salinity that requires specific attention for designing and managing the specific treatment device. Membranes, commonly used in the production of desalted water, appear to be a suitable technique to deal with these issues. In this paper, we propose a comprehensive process scheme for produced water treatment train: A Vibratory Shear Enhanced Processing (VSEP) membrane system is in charge of the secondary treatment, whereas a reverse osmosis (RO) unit realizes the tertiary treatment. Material and energy balances are carried out on the whole process, while the RO process is simulated by the IMSDesign Software by Hydranautics. We analyzed three different scenarios, at increasing produced wat...

Performance Assessment of Water Gas Shift Membrane Reactors by a Two-dimensional Model

There is currently a large world effort towards developing hydrogen power as the next generation of clean energy for both the transportation and the electricity sectors. Water gas shift is a thermodynamically limited reaction, which has to operate at low temperatures, reducing kinetics rate, and increasing the amount of catalyst required to reach valuable carbon monoxide conversions. It has been widely demonstrated that the integration of hydrogen selective membranes is a promising way to enhance water gas shift reactors’ performance: a Pd-based membrane reactor operated successfully overcoming the thermodynamic constraints of a traditional reactor thanks to the removal of hydrogen from the reaction environment. In this work, the effect of hydrogen removal in membrane water gas shift reactors will be investigated by a two-dimensional, non-isothermal model in order to analyze the water gas shift reactor performance. In particular, the effects on the reactor performance of the gas space hourly velocity, reactor temperature, pressure difference, sweeping gas flow rate, and inlet flow rate composition have been deeply assessed.

Hydrogen production using inorganic membrane reactors

Abstract: Current hydrogen production processes, which depend upon the use of fossil fuels, are discussed. The means which can be used to increase efficiency, and to enable both up- and down-scaling, are considered, in particular the use of catalysts and inorganic membranes. Biomass as an alternative energy source for the production of biohydrogen through both aerobic and anaerobic fermentation has the potential to make hydrogen a truly environmentally friendly fuel.

Simulation of Water Gas Shift Membrane Reactors by a Two-dimensional Model

Abstract Water gas shift (WGS) is a thermodynamically limited reaction which has to operate at low temperatures, reducing kinetics rate and increasing the amount of catalyst required to reach valuable CO conversions. It has been widely demonstrated that the integration of hydrogen selective membranes is a promising way to enhance WGS reactors performance: a Pd-based membrane reactor (MR) operated successfully overcoming the thermodynamic constraints of a traditional reactor thanks to the removal of hydrogen from reaction environment. In this work, the effect of hydrogen removal in membrane water gas shift reactors has been investigated by a two-dimensional, non-isothermal model in order to analyze the WGS reactor performance.

PLA Chemical Recycling Process Optimization: PLA Solubilization in Organic Solvents

The recycling of used, post-industrial and post-consumer PLA is crucial to reduce both the consumption of renewable resources for the monomer synthesis and the environmental impact related to its production and disposal. Several processes are actually available: among these, there is a particular interest on the chemical recycling of PLA with production of its monomer. The aim of this work is to analyse the PLA dissolution behaviour in different organic solvents (acetone and Ethyl lactate) at different water concentrations in order to optimize the chemical depolymerisation process of PLA. New experimental data are presented and a kinetic model is provided for a first analysis. Preliminary results suggest that acetone based solvents (i.e., acetone water mixtures at various concentrations) are more effective to solubilize the PLA rather than the Ethyl-lactate based solvent. Anyway, an increase of water concentration in the solvent phase, determines both a reduction of the solvent power and a reduction of mass transport coefficient for the two solvents tested.