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In this study, a new cost-benefit economic model for hemodialyzer reuse has been developed considering all of the direct costs (dialyzer price, disinfection fluid price, reverse osmosis water cost, personnel, and miscellaneous) as well as the number of disinfections applied to the hemodialyzer. The maximum number of disinfections/reuses for different models of hemodialyzer was estimated using statistical analysis based on the information obtained from a total of 60 adult patients on maintenance hemodialysis for approximately 4 years; from a hospital in Santiago de Cuba province, Cuba. An equal number of treatments (100) was evaluated for each hemodialyzer including 2,800 total reuses. The total cost savings for reuse/disinfection using the new economic approach is compared with the single-use modality. Obtained results by applying the proposed model indicated that the correlation between the economic advantages of the reuse/disinfection process in the total cost of the hemodialysis treatment significantly depends on the type of hemodialyzer used for the treatment, the disinfection price, the virgin hemodialyzer price, the disposal cost and its price reduction because of the number of reuses and the maximum possible reuses that could be applied to the hemodialyzer. ispartof: Engineering Science & Technology vol:3 issue:2 pages:169-187 status: accepted

Ethylene vinyl alcohol copolymer (EVOH) is one of the most commonly used barrier materials in a broad range of applications. Its outstanding gas barrier properties have already been widely investigated for oxygen (O2). However, EVOH is also gaining more attention as a barrier material against other gases and organic substances such as aromas, flavours, fuels, chemicals and even as a functional barrier. The objective of the research is to determine the barrier properties of EVOH against a selection of gases, i.e. O2 and nitrogen (N2) in varying conditions of relative humidity and temperature, and organic substances such as mineral oil saturated hydrocarbons (MOSH), mineral oil aromatic hydrocarbons (MOAH) and other non-intentionally added substances (NIAS). The permeation of the gases was determined by an online permeation setup based on the equal pressure method and consists of a permeation system connected to a gas chromatography (GC)-based detection system. A similar setup with GC-mass spectrometry (MS) was used for the organic substances. Additionally, an off-line method using a spiked donor taped on barrier and receptor were used to perform experiments modelling mineral oil migration from cardboard into foodstuff with EVOH acting as a functional barrier. The concentration of the mineral oil components was analysed by GC-MS. The research shows that EVOH is a multi-functional barrier against both gases such as O2 and N2, as well as a functional barrier against mineral oils. Three grades containing 32, 44 and 48 mol% ethylene show good O2 and N2 barrier properties and outperform other polymers such as polyethylene (PE), polypropylene (PP) and polyamide 6 (PA 6) by several orders of magnitude. Moreover, only 3 m EVOH containing 27 or 32 mol% ethylene is required as functional barrier against mineral oils and other NIAS migrating from paperboard to protect foodstuff with a shelf-life of over 2 years.

Activated carbon produced by a traditional two-step activation procedure from coffee husks (HAC) and cocoa seed husks (CAC) were used as adsorbents for Ni(II) removal in aqueous solution. Temperature, activation time and added water amount used during the activation process are studied through a model equation designed by a two-level full factorial design. Analysis of variance was used in evaluating AC in multiple response optimization to maximize the yield and adsorption capacity as system responses. The adsorption behaviour of Ni(II) was also evaluated through isotherm models of Langmuir, Freundlich and Langmuir-Freundlich. For both CAC and HAC, the Langmuir-Freundlich model is slightly superior to the Langmuir and Freundlich models. Mostly CAC adsorbs higher amount of Ni(II) than HAC.

Activated carbons (ACs) from swine manure (SM), i.e. preliminary de-watered SM cake (Mc) and solid digestate (Md) were prepared by pyrolysis and water vapour activation. Demineralisation on obtained chars after carbonization was applied as well. Additionally, the adsorption capacity of demineralised ACs towards chromium in aqueous solutions was investigated and compared to non-demineralised ACs. Demineralisation caused a decrease in mineral matter content with more than 50% and affected characteristics and adsorption behaviour of these ACs. As a result, ACs with better developed porous texture were produced. Prepared ACs with reduced ash content demonstrated higher adsorption capacity toward Cr compared to non-demineralised ACs. The adsorption kinetics were investigated by applying two kinetic models, i.e. Lagergren pseudo-first order and pseudo-second order. The pseudo-second order kinetic model provided a better fit. Better fits are obtained for the Langmuir isotherm model and therefore a monolayer coverage chemisorption of the Cr(VI) on the ACs surface is suggested. FWO; BAS-IOCh bilateral research project

VLAIO Baekeland & Kuraray EVAL Europe