Synthesis and Characterization of Greener Ceramic Materials with Lower Thermal Conductivity Using Olive Mill Solid Byproduct

In the current research, the valorization of olive mill solid waste as beneficial admixture into clay bodies for developing greener ceramic materials with lower thermal conductivity, thus with increased thermal insulation capacity towards energy savings, is investigated. Various clay/waste mixtures were prepared. The raw material mixtures were characterized and subjected to thermal gravimetric analysis, in order to optimize the mineral composition and maintain calcium and magnesium oxides content to a minimum. Test specimens were formed employing extrusion and then sintering procedure at different peak temperatures. Apparent density, water absorption capability, mechanical strength, porosity and thermal conductivity were determined on sintered specimens and examined in relation to the waste percentage and sintering temperature. The experimental results showed that ceramic production from clay/olive-mill solid waste mixtures is feasible. In fact, the mechanical properties are not significantly impacted with the incorporation of the waste in the ceramic body. However, the thermal conductivity decreases significantly, which can be of particular interest for thermal insulating materials development. Furthermore, the shape of the produced ceramics does not appear to change with the sintering temperature increase

Effect of system parameters and of inorganic salts on the decolorization and degradation of Procion H-exl dyes. Comparison of H2O2/UV, Fenton, UV/Fenton, TiO2/UV and TiO2/UV/H2O2 processes

Reactive dyes are extensively used in the last years due to their superior performance, but they are environmentally hazardous. In the present work, the decolorization and degradation of commercial reactive azo dyes (Procion Navy H-exl, Procion Crimson H-exl and Procion Yellow H-exl) were studied using five advanced oxidation processes (AOPs): H2O2/UV, Fenton, UV/Fenton, TiO2/UV and TiO2/UV/H2O2. The dependence of the decolorization on the system parameters (solution pH, dye and reactants initial concentrations, and TiO2 loading) and on the presence of salts (NaCl, Na2CO3, NaHCO3, Na2SO4, NaNO3 and Na3PO4) was investigated. The decolorization (determined by spectrophotometric analysis) and the degradation (determined as TOC reduction) were compared for the different processes examined. The decolorization of the Procion H-exl solutions considered was found to strongly depend on the system parameters in all five AOPs. Although decolorization is very fast for the Fenton process and becomes even faster for the UV/Fenton process, degradation rates are relatively low for these two methods. Addition of H2O2 increases the decolorization and especially the degradation rates for the TiO2/UV process. The H2O2/UV and TiO2/UV/H2O2 processes result in the fastest dye degradation. The addition of the salts examined has in general an adverse effect on the decolorization rates, but to a varying degree depending on the salt used

Decolorization kinetics of Procion H-exl dyes from textile dyeing using Fenton-like reactions

The decolorization kinetics of three commercially used Procion H-exl dyes was studied using a Fenton-like reagent. The effect of the major system parameters (pH, concentration of H2O2 and Fe3+ and initial dye concentration) on the kinetics was determined. For comparison, the effect of the use of UV irradiated Fenton-like reagent and of Fenton reagent on the kinetics was also examined. In addition, mineralization rates and the biodegradability improvement as well as the effect of the addition of Cl-, Co-3(2-) or HCO3- on the decolorization rates was studied. The reactions were carried out in a 300 ml stirred cylindrical reactor with the capability of UV irradiation. The dye half-life time goes through a minimum with respect to the solution pH between 3 and 4. It also exhibits a broad minimum with respect to Fe3+ and H2O2 at molar ratios of H2O2/Fe3+ from about 100 to 10. The addition of CO32- and HCO3 substantially reduces the decolorization rates, while this effect is significantly less pronounced with Cl-. At an optimum range of parameters, the mineralization rate (TOC reduction) is very slow for the Fenton-like process (TOC decrease from an initial 49.5 to 41.1 mg/l after 30 min and to only 35.2 mg/l after 600 min), but it increases significantly for the photo-Fenton-like process (to TOC values of 39.7 and 11.4 mg/l, respectively). The biodegradability, as expressed by the BOD/COD ratio, increases significantly from an initial value of 0.11-0.55 for the Fenton-like and to 0.72 for the photo-Fenton-like processes. (c) 2005 Elsevier B.V. All rights reserved

Synthesis and characterization of greener ceramic materials with lower thermal conductivity using olive mill solid byproduct

In the current research, the valorization of olive mill solid waste as beneficial admixture into clay bodies for developing greener ceramic materials with lower thermal conductivity, thus with increased thermal insulation capacity towards energy savings, is investigated. Various clay/waste mixtures were prepared. The raw material mixtures were characterized and subjected to thermal gravimetric analysis, in order to optimize the mineral composition and maintain calcium and magnesium oxides content to a minimum. Test specimens were formed employing extrusion and then sintering procedure at different peak temperatures. Apparent density, water absorption capability, mechanical strength, porosity and thermal conductivity were determined on sintered specimens and examined in relation to the waste percentage and sintering temperature. The experimental results showed that ceramic production from clay/olive-mill solid waste mixtures is feasible. In fact, the mechanical properties are not significantly impacted with the incorporation of the waste in the ceramic body. However, the thermal conductivity decreases significantly, which can be of particular interest for thermal insulating materials development. Furthermore, the shape of the produced ceramics does not appear to change with the sintering temperature increase. © The Author(s) 2020

Decolorization and degradation of reactive azo dyes via heterogeneous photocatalytic processes

Reactive dyes are extensively used in textile industry in the last years due to their superior performance, but they are environmentally hazardous and difficult to treat effectively by classical methods. In the present work. the decolorization and degradation of four commercial reactive azo dyes, namely Remazol Red RR, Remazol Yellow RR, Procion Crimson H-exl and Procion Yellow H-exl. were studied using photocatalytic processes (TiO(2)/UV and TiO(2)/UV/H(2)O(2)). Decolorization and degradation were found to strongly depend on the system parameters (TiO(2) loading, dye and H(2)O(2) initial concentrations, and pH). Decolorization efficiency (%) sharply increases with increasing the TiO(2) loading. especially up to 1 g/L, as well as with decreasing the initial dye concentration from 250 down to 50 mg/L At pH = 3, a > 90% decolorization of all dyes can be achieved in only 15 min. Addition of H(2)O(2) increases the decolorization rates up to an optimum value (97.9% Remazol Red RR decolorization at 12 min irradiation, with a 0.5%w/w initial H(2)O(2) concentration and pH = 3). Among the four dyes examined, significant differences in decolorization and degradation rates were revealed, but decolorization and degradation efficiencies up to 100% (in 25 min and 4 h respectively) are possible with proper combinations of the system parameters. (C) 2009 Elsevier B.V. All rights reserved