Improved recycling of a gasification fly ash: An integrated waste management approach within the framework of a Circular Economy.

A Circular Waste Management alternative is considered in this paper in which a complete ash valorization process is proposed for an Integrated Gasification with Combined Cycle fly ash, trying to extract maximum value from this waste before it is discarded. In the paper, germanium, a scarce resource vital in our modern society, is first extracted from fly ash using water, with an extraction yield of 85%, and subsequently, the leached fly ash is used in the manufacture of fire-resistant boards containing 60% ash, thereby avoiding its disposal in a landfill. The potential environmental impact caused by the two stages of the process was analyzed, and the final effluent was considered to achieve a zero-discharge objective. This paper contributes to the development of a more sustainable management alternative for an industrial waste produced in increased amounts and provides the basis for a symbiotic coupling relationship among various industrial sectors.

The role of dopamine receptors in lymphocytes and their changes in schizophrenia.

Dopamine and its 5 receptors, which are grouped into two families (D1-like and D2-like), modulate functions at a systemic level in both the central nervous system and periphery. The central nervous system and the immune system are the main adaptive systems, which participate in a continuous and functional crosstalk to guarantee homeostasis. On binding to its 5 dopamine receptors, dopamine acts as a co-regulator of the immune system, contributing to the interaction of the central nervous system and inflammatory events and as a source of communication between the different immune cells. Dopaminergic perturbations in the central nervous system are observed in several neurological and psychiatric disorders. Schizophrenia is one of the most common mental disorders with a poorly understood pathoaetiology that includes genetic and environmental components that promote alterations in the dopaminergic system. Interestingly, abnormalities in dopamine receptors expression in lymphocytes of schizophrenia patients have been reported, often significantly correlating with the severity of the psychotic illness. Here, we review the current literature regarding the dopaminergic system in human lymphocytes and its alterations in schizophrenia.

Environmental risks and mechanical evaluation of recycling red mud in bricks.

More and more by-products are being used in certain materials, especially in the construction industry. Natural construction materials contain amounts of heavy metals and radionuclides, but when by-products are used in these kinds of materials, this could lead to a growth in their concentrations and have a negative impact on public health.In this paper, red mud was used as a raw material (as a clay substitute) to manufacture fired bricks. Physical, mechanical, radiological and heavy metal leaching properties of fired bricks with a replacement ratio of up to 80 wt% of clay to red mud are discussed. In addition, the effect of different sintering temperatures (1173K and 1373K) was analyzed, and results showed that the higher the temperature produced, the higher the mechanical strength.To environmentally characterize materials, they were subjected to two different leaching tests: a batch test for raw materials and a monolithic test for the bricks, respectively. The results obtained were compared with the limits stated for several heavy metals by the European Landfill Directive. Results showed that red mud gives leachate concentration values for Cr higher than the limits stated for non-hazardous by-products. Bricks do not exhibit the same problem in the samples containing a high RM proportion and manufactured at a low sintering temperature (1173K), although in the case of V, a high concentration is observed.The contents of radionuclides such as Ra-220, Th-232 and K-40 of the final construction materials were analyzed and compared with different indexes. This paper indicates the maximum amounts of RM that can be used to replace clay for the manufacture of fired bricks without environmental risk.

A porous geopolymer based on aluminum-waste with acoustic properties.

Paval, a solid waste stream from the aluminum industry, is used as a pore generation agent in geopolymers. Paval was mixed with coal combustion fly ash, as a geopolymeric precursor, and activated with alkaline solution with the aim of obtaining porous geopolymers to be used as noise barriers. Both geopolymeric and pore generation reactions happen simultaneously. Aluminum from Paval can react with water and OH¯ from the geopolymerization activating solution, producing hydrogen. The hydrogen gas released generates a highly porous material. The influence of the fly ash-paval proportion and the setting temperature on open porosity, compressive strength and noise-absorbing properties were evaluated. To better understand these influences, the setting time, volume expansion and mineral composition were also studied. The obtained results showed that a higher Paval content (fly ash-Paval ratio 50:50) and setting temperature (70 °C) produced a lower setting time and higher volume expansion, increasing the open porosity and improving acoustic properties, but reducing the compressive strength. The material manufactured under these conditions showed similar amorphous phase content to the non-porous geopolymers made without Paval. On the other hand, the obtained materials did not raise environmental concerns in a normalised leaching test.

Stabilization/solidification of a municipal solid waste incineration residue using fly ash-based geopolymers.

The stabilization/solidification (S/S) of a municipal solid waste incineration (MSWI) fly ash containing hazardous metals such as Pb, Cd, Cr, Zn or Ba by means of geopolymerization technology is described in this paper. Different reagents such as sodium hydroxide, potassium hydroxide, sodium silicate, potassium silicate, kaolin, metakaolin and ground blast furnace slag have been used. Mixtures of MSWI waste with these kinds of geopolymeric materials and class F coal fly ash used as silica and alumina source have been processed to study the potential of geopolymers as waste immobilizing agents. To this end, the effects of curing conditions and composition have been tested. S/S solids are submitted to compressive strength and leaching tests to assess the results obtained and to evaluate the efficiency of the treatment. Compressive strength values in the range 1-9 MPa were easily obtained at 7 and 28 days. Concentrations of the metals leached from S/S products were strongly pH dependent, showing that the leachate pH was the most important variable for the immobilization of metals. Comparison of fly ash-based geopolymer systems with classical Portland cement stabilization methods has also been accomplished.

Use of FGD gypsum in fire resistant panels.

Gypsum from power plant flue gas desulphurization units (FGD gypsum) is a combustion by-product produced in high quantities. In this paper, gypsum panels composed of 100% FGD gypsum from two power plants have been subjected to different physico-chemical (density, pH, humidity), mechanical (flexural and compressive strength, surface hardness, impact resistance), fire resistance and environmental tests (leaching and radioactivity). The results obtained have been compared with the requirements established in some European standards for commercial gypsum and other standards for similar products. In addition, the panels manufactured have been compared with commercial gypsum panels in order to determine the recycling possibilities of this kind of material in this application.

Use of zeolitised coal fly ash for landfill leachate treatment: a pilot plant study.

Treatment of municipal solid waste (MSW) landfill leachate generally results in low percentages of nutrient removal due to the high concentration and accumulation of refractory compounds. For this reason, individual physical, chemical and biological processes have been used for the treatment of raw landfill leachate and sometimes for the mixture of domestic wastewater and landfill leachate. In this work, the possibility of treating landfill leachate was tested in a bench-scale pilot plant by a two-step method combining adsorption and coagulation-flocculation. Zeolite synthesized from coal fly ash, a by-product of coal-fired power stations, was used in this study both as a decantation aid reagent and as an adsorbent of COD and NH4-N. The coagulation-flocculation step was performed by the use of aluminium sulphate and a polyelectrolyte (ACTIPOL A-401). The leachate was collected directly from a storage unit of the organic fraction of MSW, before it was composted. For this reason the raw leachate was diluted before treatment. The sludge was recirculated to enhance the removal efficiency of nutrients as well as to optimize flocculant saving and to decrease sludge production. The results showed that it is possible to remove 43%, 53% and 82% of COD, NH4-N, and suspended solids, respectively. Therefore, this method may be an alternative for ammonium removal, as well as a suitable pre- or post-treatment step, in combination with other processes in order to meet regulatory limits.

Role of oral rapamycin to prevent restenosis in patients with de novo lesions undergoing coronary stenting: results of the Argentina single centre study (ORAR trial).

OBJECTIVE: To assess the role of oral rapamycin in the prevention of coronary restenosis in patients undergoing coronary stenting. METHODS: From December 2001 through February 2003, 76 patients with 103 de novo lesions treated percutaneously with bare stents received a loading dose of oral rapamycin 6 mg followed by a daily dose of 2 mg during 28 days in phase I (49 arteries in 34 patients) and 2 mg/day plus 180 mg/day of diltiazem in phase II (54 arteries in 42 patients). Rapamycin blood concentrations were measured in all patients. A six month follow up angiogram was performed in 82.5% (85 of 103 arteries). Follow up angiographic binary restenosis (> 50%), target vessel revascularisation, late loss, treatment compliance, and major adverse cardiovascular events were analysed and correlated with rapamycin concentrations. RESULTS: Rapamycin was well tolerated and only three patients discontinued the treatment for mild side effects. Angiographic restenosis was found in 15% of the arteries with angiographic restudy (13 of 85). The target vessel had been revascularised at follow up in 13.6% of the 103 vessels initially treated (14 of 103) and in 18.4% of the 76 patients (14 of 76). In-stent restenosis in phase I was 19% compared with 6.2% in phase II (p = 0.06). Angiographic in-stent restenosis in lesions of patients with rapamycin blood concentrations > or = 8 ng/ml was 6.2% and with rapamycin concentrations < 8 ng/ml was 22% (p = 0.041). Late loss was also significantly lower when rapamycin concentrations were > or = 8 ng/ml (0.6 mm v 1.1 mm, p = 0.031). A Pearson test showed a linear correlation between follow up late loss and rapamycin blood concentration (r = -0.826, p = 0.008). CONCLUSION: Oral rapamycin administered for one month after percutaneous coronary intervention was safe and with few minor side effects. High rapamycin blood concentrations were associated with significantly lower late loss and angiographic in-stent restenosis.

Coronary stenting versus coronary bypass surgery in patients with multiple vessel disease and significant proximal LAD stenosis: results from the ERACI II study.

PURPOSE: To compare percutaneous coronary intervention (PCI) using stent implantation versus coronary artery bypass graft (CABG) in patients with multiple vessel disease with involvement of the proximal left anterior descending coronary artery (LAD). METHODS: 230 patients with multiple vessel disease and severe stenosis of the proximal LAD (113 with PCI, 117 with CABG). They were a cohort of patients from the randomised ERACI (Argentine randomized trial of percutaneous transluminal coronary angioplasty versus coronary artery bypass surgery in multivessel disease) II study. RESULTS: Both groups had similar baseline characteristics. There were no significant differences in 30 day major adverse cardiac events (death, myocardial infarction, stroke, and repeat procedures) between the strategies (PCI 2.7% v CABG 7.6%, p = 0.18). There were no significant differences in survival (PCI 96.4% v CABG 95%, p = 0.98) and survival with freedom from myocardial infarction (PCI 92% v CABG 89%, p = 0.94) at 41.5 (6) months' follow up. However, freedom from new revascularisation procedures (CABG 96.6% v PCI 73%, p = 0.0002) and frequency of angina (CABG 9.4% v PCI 22%, p = 0.025) were superior in the CABG group. CONCLUSION: Patients with multivessel disease and significant disease of the proximal LAD randomly assigned in the ERACI II trial to PCI or CABG had similar survival and survival with freedom from myocardial infarction at long term follow up. Repeat revascularisation procedures were higher in the PCI group.

Stabilization of a chromium-containing solid waste: immobilization of hexavalent chromium

This article describes the stabilization/solidification (S/S) of a steel industry waste, using a common type-F fly ash from a coal power station as the main binder. The waste, which contains hazardous levels of metals, may be stabilized by a conventional S/S to achieve permissible Pb, Cd, and Zn concentrations in the Toxicity Characteristic Leaching Procedure (TCLP) leachates of S/S solids. On the other hand, the stabilization of Cr(VI), also present in the waste, requires a reducing pretreatment stage with ferrous sulfate to attain TCLP leachates within limits. A bibliographic study on the stabilization of Cr(VI)-containing wastes is included in the paper, along with a discussion on the lowest Cr concentration in TCLP and aqueous (DIN) leachates.

Application of ion chromatography to the determination of inorganic anions in foodstuffs.

A review on the applications of ion chromatography (IC) to the determination of inorganic anions in foodstuffs is presented. The anions were commonly determined in food, i.e., SO3(2-), NO3- and NO2-, and to a lesser extent Cl-, Br-, I-, SO4(2-), IO3-, BrO3- and phosphate, are considered. In comparison with standard methods for the determination of anions in food products, chromatographic methods are rapid, sensitive and precise. They also have the advantage of determining several ions simultaneously. The separation may be achieved by conventional IC, by ion interaction chromatography or by ion exclusion chromatography. IC has also been applied to the determination of Br, I, N and S in foods after oxidation or combustion of samples and conversion into anionic forms.

The importance of metallic elements in wine. A literature survey.

A review of the current literature concerning the role played by metallic elements present in wine is presented. The aim is to show the importance of these elements in the entire wine-making process, mainly through their influence on the organoleptic properties of wine. The study takes into consideration the individual stages of the process such as fertilization, fermentation and aging and also deals with other interesting aspects related to hygiene and dietetic properties, as well as the possibility of differentiating wines according to their metal contents.