High performance fluidized bed photoreactor for ethylene decomposition

Removal of C2H4 in the air was carried out in the continuous flow reactor with the photocatalytic bed (expanded polystyrene spheres coated by TiO2 or SiO2/TiO2) under irradiation of UV light. Continuous flow of a gas stream through the reactor was realised at the static bed and under bed fluidization. The required flow of a gas stream through the reactor for bed fluidisation was 500–700 ml/min, whereas for the static bed the flow rate of 20 ml/min was used. Fluidized bed reactor appeared to be much more efficient in ethylene removal than that with the stationary bed. It was caused by the increased speed of C2H4 mass transfer to the photocatalyst surface and better utilization of the incident UV light. In the fluidized bed reactor calculated rate of C2H4 degradation was around 10 μg/min whereas in the stationary state 1.2 μg/min only

Development of activated carbon for removal of pesticides from water: case study

Abstract The work primarily concerns development of activated carbon dedicated for adsorption of pesticides from water prior directing it to the distribution system. We provide an information on research on important practical aspects related to research carried out to develop and to manufacture activated carbons. The paper concerns preliminary works on selection raw materials, a binder used for producing granulated adsorbent, activating gases, conditions of the production process, and others. The key attention in this research was paid to its target, i.e., industrial process to produce activated carbon revealing fulfilling required properties including satisfying adsorption of selected pesticides and meeting the requirements of companies dealing with a large-scale production of drinking water. Therefore, among others, the work includes considerations concerning such aspects like pore structure and specific surface area of the activated carbon, formation of granules that are the most demanded and thus preferred in an industrial practice form of activated carbons, and other aspects important from practical point of view. Using the results of our preliminary work, a batch of granular activated carbon was produced in industrial conditions. The obtained material was tested in terms of removing several pesticides at a water treatment plant operating on an industrial scale. During tests the concentration of acetochlor ESA was decreased from ca. 0.4 µg/l in raw water to below 0.1 µg/l. During 11 months of AC use specific surface area of adsorbent lowered significantly by 164 m2/g, and total pore volume declined from initial 0.56 cm3/g to 0.455 cm3/g. We discuss both a performance of the obtained activated carbon in a long-term removal of acetochlor and its derivatives from water and an effect of exploitation time on the removal efficiency. The explanations for the reduction in pesticide removal efficiency are also proposed and discussed

Epoxidation of natural limonene extracted from orange peels with hydrogen peroxide over Ti-MCM-41 catalyst

The paper presents the oxidation of natural limonene (extracted from waste orange peels) by 60 wt% hydrogen peroxide, in the presence of Ti-MCM-41 catalyst and in methanol as the solvent. The aim of the research was to develop the most favorable technological parameters for the process of limonene oxidation (temperature, molar ratio of limonene to hydrogen peroxide, methanol concentration, Ti-MCM-41 catalyst content and reaction time) by analyzing changes in the main functions describing this process: the conversion of limonene, selectivities of appropriate products, the conversion of hydrogen peroxide and the effective conversion of hydrogen peroxide. The process is environmentally friendly process and it uses renewable raw material - limonene and a safe oxidant -hydrogen peroxide. During the study, very valuable oxygenated derivatives of limonene were obtained: 1,2-epoxylimonene, its diol, carvone, carveol, and perillyl alcohol. These compounds are used in medicine, cosmetics, perfumery, food and polymers industries

Conversion of Geraniol into Useful Value-Added Products in the Presence of Catalysts of Natural Origin: Diatomite and Alum

This article presents research related to the transformation of geraniol (GA), leading to the formation of products with very valuable properties. In the planned method, heterogeneous catalysts of natural origin in the form of alum and diatomite were used as catalysts. Initially, the process which we investigated was the process of isomerization of GA, but it turned out during the studies that GA is also transformed in other reactions. Before catalytic tests, these two minerals were subjected to detailed instrumental analyses using the following methods: XRD, SEM/EDX, XRF and FTIR, which allowed to obtain their full morphological characteristics. During the catalytic tests, the influence of such relevant parameters on the GA transformations was determined: temperature from 80 to 150 °C, catalyst content from 5 to 15% by weight and the reaction time from 15 min to 24 h. The tests presented in the article were carried out under atmospheric pressure (in air) as well as without the use of a solvent. The optimal conditions for the transformations of GA were determined on the basis of its conversion and selectivities of transformation to the main products in the form of: beta-pinene (BP), 6,11-dimethyl-2,6,10-dodecatriene-1-ol (DC) and thumbergol (TH). The above products were formed with the highest selectivity, respectively: 100 mol%, 50 mol% and 52 mol%. The results of the syntheses showed that for GA the best transformation results were obtained at the temperature of 80 °C (for both tested catalysts), with the catalyst content of 1 wt % (for both tested catalysts) and for the reaction time of 1 h (for diatomite)) and 3 h (for alum)

Influence of diatomite and its base modifications on the self-adhesive properties of silicone pressure-sensitive adhesives

Abstract The study examined how diatomite and its modifications affected the self-adhesive ability of silicone pressure-sensitive adhesives. To create adhesive composition for testing, fillers were added to a commercial silicone resin, which were then used to create new modified pressure-sensitive tapes. The resulting tapes were tested to determine their adhesion, tack, cohesion at room and elevated temperature, SAFT test (Shear Adhesive Failure Temperature), pot-life (viscosity) and shrinkage. The results obtained were compared with those of the unmodified tapes. The tests resulted in higher thermal resistance (225 °C) and lower shrinkage (0.1%). As a result, we can conclude that materials with thermal resistance with a slight decrease in other parameters were obtained

Green method of conversion of geraniol to value-added products in the presence of selected minerals

The study presents the results of research on the process of geraniol (GA) transformation in the presence of natural minerals: montmorillonite, mironekuton, halloysite and also in the presence of halloysite modified with 0.1 M water solution of H2SO4. To obtain information on the structure of the used catalysts, instrumental studies were performed (SEM, XRD, FT-IR, XRF, BET). The second part of the research consisted in examining the influence of individual parameters (temperature, catalyst content, and reaction time) on the course of GA transformation process. The syntheses were carried out without the application of solvent and under atmospheric pressure. To determine the most beneficial process conditions, two functions were selected: GA conversion and selectivity of GA. The proposed method of GA transformation on such minerals: montmorillonite, mironekuton, halloysite, has not been described in the literature so far

Influence of Technological Parameters on the Isomerization of Geraniol Using Sepiolite

In the current study, the isomerization of geraniol over a natural sepiolite as a catalyst was investigated and optimized. Prior to application in the isomerization process, the physical and chemical properties of sepiolite were characterized using a battery of instrumental techniques, including XRD, nitrogen adsorption at 77 K, SEM, EDXRF, UV–Vis and FT-IR. Results indicated that geraniol isomerization is very complicated due to the large number of reactions taking place. The catalytic studies showed that the main reaction products were β-pinene, ocimenes, linalool, nerol, citrals, thunbergol and isocembrol; all chemical products with commercial applications. The quantity of each of these products depended on the temperature, catalyst content and reaction time employed in the isomerization process. During the current study, these parameters were varied in a step-wise approach over the ranges 80–150 °C (temperature), 5–15 wt% catalyst content and reaction time of 15–1440 min. As linalool is one of the most commercially important reaction products, the geraniol isomerization method was studied to identify conditions producing the highest selectivity for this compound. The most beneficial conditions for geraniol conversion and linalool formation were established as a temperature of 120 °C, catalyst content of 10 wt% and a reaction time of 3 h.Influence of Technological Parameters on the Isomerization of Geraniol Using SepiolitepublishedVersio

W-SBA-15 as an Effective Catalyst for the Epoxidation of 1,5,9-Cyclododecatriene

The results of a study on the epoxidation of 1,5,9-cyclododecatriene (CDT) on a W-SBA-15 catalyst using the batch and half-periodic methods are presented. During this study, the activity of the W-SBA-15 catalyst was compared to that of the Ti-SBA-15 catalyst, and the W-SBA-15 catalyst was found to be about 20 times more active than the Ti-SBA-15 catalyst. The highest CDT conversion so far, amounting to 86 mol%, was obtained after carrying out the 4 h epoxidation process. Conducting the studied process using the semi-batch method did not result in the significant improvement in value functions describing this process (CDT conversion and selectivity of CDT transformation to ECDD), but the fastest H2O2 dosing rate (246 µL/h) allowed us to obtain 9 mol% higher CDT conversion in comparison to the batch method

Organophilized Montmorillonites as Fillers for Silicone Pressure-Sensitive Adhesives

In the presented work, organophilized montmorillonites (OMMT) with selected quaternary ammonium compounds (QAC) with different chemical structure ((trioctylmethylammonium chloride—A336, dimethyloctadecyl[3-trimethoxysilyl)propyl]ammonium chloride—D, cetyltrimethylammonium bromide—CTAB, 2-methacryloxyethyltrimethylammonium chloride—MOA) were obtained and used as fillers for physically modified silicone pressure-sensitive adhesives (Si-PSA). Before OMMT addition into Si-PSA matrix, they were analyzed via TGA and XRD techniques. Type of chemical structure of QAC affected d-spacing of OMMT. New self-adhesive materials were obtained based on prepared Si-PSA compositions by adding the obtained fillers to the polymer matrix. New tapes exhibit a good level of useful properties as adhesion, cohesion, and tack—the values did not change or slightly decreased; in addition, the tapes with addition of OMMT showed high thermal resistance reaching the measuring limit of the test equipment—to 225 °C

Effect of extraction method on the antioxidative activity of ground elder (Aegopodium podagraria L.)

In this work the studies on the antioxidative properties of extracts from various morphotic parts of the ground elder (leaves, rhizomes, seeds and flowers) were presented. Moreover, the effect of different extraction methods (ultrasonic assisted extractions, extraction in a Soxhlet apparatus, extraction at the boiling point of the solvent used), solvent and its amount, and extraction time on the antioxidative properties of the obtained extracts were tested. The studies showed that all parts of ground elder can show radical scavenging activity, and it depends mainly on the method of extraction and extraction time. But the most beneficial is ultrasonic assisted extraction which used lower amount of solvent (ethanol). In case of all parts of the ground elder (leaves, rhizomes, seeds and flowers) it allows to obtain very high values of the antioxidant capacity (above 90%) for very short extraction time amounted to 20–40 minutes