Effectiveness in the Removal of Organic Compounds from Municipal Landfill Leachate in Integrated Membrane Systems: Coagulation – NF/RO

The article presents the results of studies concerning the hydraulic permeability of integrated membrane systems during the treatment of municipal landfill leachate. The laboratory-scale experiments were conducted to determine the effectiveness of coagulation as a pretreatment option for treating stabilized landfill leachate and effectiveness of nanofiltration (NF) and reverse osmosis (RO) processes. The municipal landfill leachates were analyzed for the concentration of the following: polycyclic aromatic hydrocarbons (PAHs), nitrate nitrogen, ammonium nitrogen, chemical oxygen demand (COD), total organic carbon (TOC), total carbon (TC), suspended soils (SS), turbidity, pH. The commercially available coagulant – aluminum sulfate Al₂(SO₄)₃·18H₂O (alum) was used as a coagulant. The NF process was carried out at the transmembrane pressure of 1.5 MPa. The membrane separation process was based on a thin film membrane (DK). The transmembrane pressure of the RO stood at 2 MPa and for this process one polyamide membrane (AG) was used. The level of leachate treatment was defined for raw and cleaned wastewater indicators. Both NF and RO membranes allowed obtaining the high level of pollutants removal. In the coagulation–NF system, the removal efficiency was equal to 77% for PAHs, 88% for COD, 72% for ammonium nitrogen, 80% for nitrate nitrogen, 67% for TOC, 80% for TC, 96% for SS and during the RO – 86% for PAHs, 98% for COD, 93% for ammonium nitrogen, 87% for nitrate nitrogen, 89% for TOC, 100% for TC, 98% for SS. The calculations based on the assumptions of the mathematical filtration model (relaxation) made it possible to predict the efficiency of commercial filtration membranes used for leachate treatment.     

Reactivity of perovskite-type precursor in MWCNTs synthesis

Ni catalysts were tested in the synthesis of multi-wall carbon nanotubes (MWCNTs) by catalytic decomposition of methane at low temperature. The selectivity of MWCNTs formation was determined using transmission electron microscopy (TEM). The catalytic performance of the supported-Ni catalysts obtained by perovskite reduction was discussed based on the X-ray diffraction (XRD), TEM and scanning electronic microscopy (SEM) results. The characteristics of the nanotubes obtained by decomposition of methane were mainly dependent on the homogeneity of nickel particles and less on the reaction conditions.     

Influence of different types of the internal system of the ballistic helmet shell on the thermal insulation measured by a manikin headform

The head is a part of the body whose temperature influences not only physiological parameters of the whole body but also the perception of a thermal environment and psychomotor parameters of a human. For this reason, it is important to prevent the head from overheating and to use head covers which render it possible to release heat from head surface to the environment.     

Dyes derived from 1,4‐naphthoquinone as initiators for radical and cationic photopolymerisation

Several 2‐phenylamino‐1,4‐naphthoquinone‐based dyes and two related benzo[2,3‐b]–phenazines were synthesised and characterised by proton nuclear magnetic resonance spectroscopy and electron ionisation mass spectrometry. The electrochemical and spectral properties of these compounds were investigated. The synthesised dyes were found to be capable photosensitisers for radical (reducible/oxidisable) and cationic polymerisations, respectively. In radical polymerization, better results in the oxidisable process were achieved.     

Alternative Local Melting-Solidification of Suspended Nanoparticles for Heterostructure Formation Enabled by Pulsed Laser Irradiation

Phase formation by pulsed laser irradiation of suspended nanoparticles has recently been introduced as a promising synthesis technique for heterostructures. The main challenge still lingers regarding the exact mechanism of particle formation due to the non-equilibrium kinetic by-products resulting from the localized alternative, fast, high-temperature nature of the process. Here, the authors analyze the bond breaking/formation of copper or copper (II) interfaces with ethanol during the absorption of pulses for Cu-CuO-Cu₂O formation applicable as an electrocatalyst in ethanol oxidation fuel cells. This study includes but is not limited to, a comprehensive discussion of the interaction between nano-laser pulses and suspension for practical control of the synthesis process. The observed exponential and logarithmic changes in the content of heterostructures for the CuO-ethanol and Cu-ethanol samples irradiated with different fluences are interpreted as the dominant role of physical and chemical reactions, respectively, during the pulsed laser irradiation of suspensions synthesis. It is also shown that the local interface between dissociated ethanol and the molten sphere is responsible for the oxidative/reductive interactions resulting in the formation of catalytic-augmented Cu³⁺ by-product, thanks to the reactive bond force field molecular dynamics studies confirmed by ab-initio calculations and experimental observations.     

1H magnetic resonance spectroscopy of the brains of normal infants and after perinatal hypoxia-ischemia

The aims of this study were to define proton (¹H) metabolite peak-area ratios in the brains of normal infants and to investigate abnormalities after perinatal hypoxia-ischemia. Point-resolved spectroscopy (PRESS) data were collected at 2.4 T with an echo time (TE) of 270 ms from 8-ml voxels located in the thalamus or occipito-parietal region. Fourteen normal and 9 asphyxiated infants were studied. The gestational plus postnatal ages (GPA) of these two groups were 31–41 (median 36) and 27–41 (37) weeks, respectively, and the asphyxiated infants were studied aged 0–10 (2) days. Peak-area ratios were determined in the normal infants for choline-containing compounds (Cho), creatine plus phosphocreatine (Cr),N-acetylaspartate (NAA) and lactate (Lac). Lactate was detected in all the normal infants and Lac/NAA was higher in the occipito-parietal region than in the thalamus (p<0.005). Lac/NAA decreased with increasing GPA in both the thalamus (p=0.014) and the occipito-parietal region (p=0.033). In six of the nine asphyxiated infants, Lac/NAA was above 95% confidence intervals for either the thalamus and/or the occipito-parietal region. Of these six infants, two died and three were neurologically abnormal aged 2 months, indicating that elevated Lac/NAA after perinatal hypoxia-ischemia may convey a poor prognosis. Propan-l,2-diol (the phenobarbitone injection medium) was detected at 1.1 ppm in three infants.     

The interrelation of changes in oxygen content and product quality in modified atmosphere packages of peanuts

The aim of this work was to examine the effect of changes in oxygen content in different types of packages for snacks (multilayer laminated materials, cans) and analyse the changes in the sensorial and physicochemical characteristics of the stored products. Roasted and salted peanuts produced by one of the well‐known companies, packed in modified atmosphere packages (MAP) were the object of this investigation. The interdependence of the changes in oxygen content and product quality was examined in relation to the storage period and type of package used. From the results it can be said that changes in oxygen content in packages of peanuts produce similar effects irrespective of the packaging material used. The correlation observed during storage of peanuts, between changes in oxygen content in different packaging materials and changes of the separate sensorial and physicochemical parameters of the product, especially of the peroxide value, may be a basis for validity forecasting and determination of the optimum composition of gas mixture. This study indicates that evaluation of the quality of packages integrally related to their content should consider both product examination and the package and gas mixture composition, as there may exist an interdependence between quality features of the product and oxygen content in a package. Copyright © 2001 John Wiley & Sons, Ltd.