An enhancement of wettability of PET foils pretreated hydrolytically by immersing in mild alkaline (NaOH) solutions has been documented by a descending sigmoidal dependence between the interfacial free energy γ SL of the PET/water interface and the concentration of NaOH solution c NaOH . An increase in temperature of the NaOH solution below the glass-transition temperature of PET further promotes the hydrophilicity, resulting in a proportional shift of the γ SL vs c NaOH dependence. The limiting hydrophilicity of PET is thermodynamically predicted to occur at γ SL f 0, corresponding to the advancing water contact angle θ a ≈ 50°(for 6% NaOH and 60 °C). The surface roughness due to the partial hydrolytic degradation as well as the weight loss (dissolution) of PET are found to reach a maximum value just when the latter dependence goes through its inflection. Assuming a general parallelism between the interfacial free energy and the dissolution kinetics, we propose the hydrolytically stimulated formation and growth of pits on the PET surface to cause the initial acceleration as well as subsequent retardation of dissolution as c NaOH increases, leading to the S-shaped γ SL vs c NaOH dependence with the inflection for a specific c NaOH . Moreover, the zeta potential measured by the streaming current method also attains a maximum at the same specific concentration of NaOH. It would indicate that the largest amount of electric charges is populated via polar carboxyl and hydroxyl groups created by chemical scissions of PET polymer chains when a change in the dissolution rate increases to the utmost. In such a way, partial hydrolysis restricted to the uppermost part of moderately hydrophobic surface of solid PET allowed us to better understand the intermingled role of thermodynamic and physical aspects in surface wettability itself.

The formation of geopolymers from fly ash (FA) and metakaolin (MK) was investigated. The effect of different reactivity of FA and MK was studied by X‐ray photoelectron spectroscopy method. Geopolymer materials were obtained by an alkaline activation of aluminosilicate sources. The aim of this work is to develop methods for working properties prediction of geopolymer materials based on the starting materials. Selection of a geopolymerization scheme is found to be a key factor to realize a beneficial effect of improved reactivity. Finally, a descriptive model of the mechanism of geopolymer formation, taking into account the quality of starting materials was proposed. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 841–849, 2015

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Our paper is focused on data evaluation about the full recycling of waste by special statistical software and by using the principles of logistics. The paper goes further than the paper entitled "Environmental assessment of waste recycling based on principles of logistics and computer simulation design," which outputs a number of data that need to be reviewed and evaluated separately. Data, representing 15 types of waste for 5 years, enter the analysis. There were the types of waste that make up the most important part of the total waste production by means of descriptive statistics. Thanks to this, they were identified as the most important (from the production point of view) plastic granules with an average of 755.05 t/month, glass with an average of 672.233 t/month and paper with the average of 645.25 t/month. The persistence of particular waste type generation was examined by the variation coefficient in order to reduce the risk of supply of these secondary raw materials in the downstream supply chain. Selected waste elements can be considered relatively stable with a variation coefficient in the range 2.4-4.1%; the least stable type is electronic dust with a coefficient of variation of up to almost 23%.

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