Decarbonatization of Energy Sector by CO2 Sequestration in Waste Incineration Fly Ash and Its Utilization as Raw Material for Alkali Activation.

In this study, municipal solid waste incineration (MSWI) fly ash was subjected to mineral carbonation with the aim of investigating CO2 sequestration in waste material. The conducted study follows the trend of searching for alternatives to natural mineral materials with the ability to sequestrate CO2. The mineral carbonation of MSWI fly ash allowed for the storage of up to 0.25 mmol CO2 g-1. Next, both carbonated and uncarbonated MSWI fly ashes were activated using an alkaline activation method by means of two different activation agents, namely potassium hydroxide and potassium silicate or sodium hydroxide and sodium silicate. Mineral carbonation caused a drop in the compressive strength of alkali-activated materials, probably due to the formation of sodium and/or potassium carbonates. The maximum compressive strength obtained was 3.93 MPa after 28 days for uncarbonated fly ash activated using 8 mol dm-3 KOH and potassium hydroxide (ratio 3:1). The relative ratio of hydroxide:silicate also influenced the mechanical properties of the materials. Both carbonated and uncarbonated fly ashes, as well as their alkali-activated derivatives, were characterized in detail by means of XRD, XRF, and FTIR. Both uncarbonated and carbonated fly ashes were subjected to TG analysis. The obtained results have proved the importance of further research in terms of high-calcium fly ash (HCFA) utilization.

Sorption of Polar Sorbates NH3, H2O, SO2 and CO2 on Selected Inorganic Materials.

In this paper, the sorption of NH3, H2O, SO2 and CO2 was tested for several selected inorganic materials. The tests were performed on samples belonging to two topologies of materials, faujasite (FAU) and framework-type MFI, the structures of which differ in pore size and connectivity. All sorbates are important in terms of reducing their emissions to the environment. They have different chemical nature: basic, alkaline, and acidic. They are all polar in structure and composition and two of them (ammonia and water vapor) can form hydrogen bonds. These differences result in different interactions with the surface of the adsorbents. This paper presents experimental data and proposes a mathematical description of the sorption process. The best fit of the experimental data was obtained for the Toth and GAB models. The studies showed that among the selected samples, faujasite has the best sorption capacity for ammonia and water vapor, while the best sorbent for sulfur dioxide is the MFI framework type. These materials behave like molecular sieves and can be used for quite selective adsorption of relevant gases. In addition, modification of the faujasite with organic silane resulted in a drastic reduction in the surface area of the sorbent, resulting in significantly lower sorption capacities for gases.

Preparation of Sorbents Containing Straetlingite Phase from Zeolitic By-Product and Their Performance for Ammonium Ion Removal.

In this study, straetlingite-based sorbents were used for NH4+ ion removal from a synthetic aqueous solution and from the wastewater of an open recirculation African catfish farming system. This study was performed using column experiments with four different filtration rates (2, 5, 10, and 15 mL/min). It was determined that breakthrough points and sorption capacity could be affected by several parameters such as flow rate and mineral composition of sorption materials. In the synthetic aqueous solution, NH4+ removal reached the highest sorption capacity, i.e., 0.341 mg/g with the S30 sorbent at a filtration rate of 10 mL/min and an initial concentration of 10 mg/L of NH4+ ions. It is important to emphasize that, in this case, the Ce/C0 ratio of 0.9 was not reached after 420 min of sorption. It was also determined that the NH4+ sorption capacity was influenced by phosphorus. In the wastewater, the NH4+ sorption capacity was almost seven times lower than that in the synthetic aqueous solution. However, it should be highlighted that the P sorption capacity reached 0.512 mg/g. According to these results, it can be concluded that straetlingite-based sorbents can be used for NH4+ ion removal from a synthetic aqueous solution, as well as for both NH4+ and P removal from industrial wastewater. In the wastewater, a significantly higher sorption capacity of the investigated sorbents was detected for P than for NH4+.

LCA and economic study on the local oxygen supply in Central Europe during the COVID-19 pandemic.

Medical oxygen is the key to survival for COVID-19 patients. To meet the pandemic-driven oxygen demand spike, local hospitals began searching for a suitable medical oxygen delivery system. Among the studies published on the impact of COVID-19 on a range of aspects, including the global economy and the environment, no study has been conducted on the environmental impact of medical oxygen supply to hospitals under epidemic conditions. In this paper the authors perform a comparative Life Cycle Assessment (LCA) to evaluate the environmental and economic impact of three scenarios (oxygen cylinders, liquid oxygen in tanks and on-site oxygen production) of local oxygen supply to hospitals in Poland. The LCA was performed according to ISO 14040 -14044 standards requirements, using the SimaPro 9.0 software. Results from the analysis showed that the Global Warming Potential (GWP) and Fine Particulate Matter Formation Potential (FPMFP) indicators for the liquid oxygen in tank scenario are the lowest and equal 265 kg CO2 eq and 0.309 kg PM2.5 eq. respectively. The greatest terrestrial acidification reductions (-1.38 kg SO2 eq) can be achieved when applying the on-site oxygen production scenario. Our findings revealed that the oxygen in cylinders scenario has the most harmful impact on the environment. The economic analysis was performed in order to compare the monthly and annual operational costs of analysed scenarios. The results show that hospitals sustain the lowest annual costs when using the on-site oxygen production scenario.

CO2 sorption and regeneration properties of fly ash zeolites synthesized with the use of differentiated methods.

Production of fly ash zeolites may be an attractive method for the utilization of solid wastes from the energy sector. Different methods of synthesis often yield a variety of zeolite types, thereby affecting the properties of the resulting materials. The attention paid to carbon dioxide emission reduction technologies fully justifies the study of the sorption behaviours of fly ash zeolites synthesized by different methods. This work investigates the sorption properties of fly ash zeolites synthesized with different methods using CO2. Sorption capacity and adsorption isotherms were determined following the volumetric method and textural parameters were resolved according to the Dubinin-Astakhov (DA) method. The CO2 sorption capacity was in the range 0.24-4.16 mmol/g. The relationships between structure and sorption behaviour were studied for each synthesis method. Some strong similarities between commercial zeolites and fly ash zeolites were found. The mechanism for sorption was proved to be physisorption which is fully reversible under selected conditions. The observed trends were used to identify the best sorbent.

SO 2 sorption properties of fly ash zeolites.

In the presented study, the sulfur dioxide sorption properties of fly ash zeolite X were investigated. Sorption tests were performed on fly ash zeolite samples that were not prepared specially for sorption, in addition to dried samples and samples in the presence of water vapor. The samples saturated with water vapor showed the highest sorption capacity. The sorption capacity of the samples additionally dried prior to the sorption experiment was higher than that of the samples that were not specially prepared for the sorption test. Regeneration tests indicated relatively good regeneration properties. The obtained results were described with the use of Langmuir, Sips, and Dubinin-Astakhov models, with the Dubinin-Astakhov model providing the best fit.

Total antioxidant status in lung cancer is associated with levels of endogenous antioxidants and disease stage rather than lifestyle factors - preliminary study.

AIM OF THE STUDY: Decreased total antioxidant capacity (TAC) has been reported in different neoplasms, including lung cancer. However, no study concerning the relationship between endogenous antioxidants, lifestyle factors, and TAC has been conducted among lung cancer patients. The purpose of the study was to investigate the associations between endogenous antioxidants, severity of disease, lifestyle factors, and TAC in lung cancer patients. MATERIAL AND METHODS: The study was conducted among 59 lung cancer patients. The levels of total antioxidant status (ATBS method), endogenous antioxidants, and C-reactive protein were measured in patients' sera automatically. Dietary habits of the subjects were evaluated based on the Food Frequency Questionnaire (FFQ) on the day of admission to hospital. RESULTS: We found a positive correlation between serum albumin, uric acid (UA), and TAC and a negative correlation between CRP and TAC. Moreover, TAC was significantly positively associated with disease stage. We did not find any significant relationship between the frequency of selected food consumption and TAC in lung cancer patients, except for a positive correlation between the frequency of refined cereal products consumption and TAC level. Smoking status did not correlate with TAC. CONCLUSIONS: Total antioxidant status of lung cancer patients results from their disease stage and levels of endogenous antioxidants rather than from lifestyle factors. The lack of influence of diet and smoking on the TAC presumably result from disturbed homeostasis in which cancer, while developing, could determine the redox state to a greater extent than lifestyle factors.

CO2 adsorption properties of char produced from brown coal impregnated with alcohol amine solutions.

Carbon dioxide (CO2) emission reduction is critical to mitigating climate change. Power plants for heating and industry are significant sources of CO2 emissions. There is a need for identifying and developing new, efficient methods to reduce CO2 emissions. One of the methods used is flue gas purification by CO2 capture through adsorption. This study aimed to develop CO2 adsorbent out of modified brown coal impregnated with solutions of first-, second-, and third-order amines. Low-temperature nitrogen adsorption isotherms and CO2 isotherms were measured for the prepared samples. The results of experiments unexpectedly revealed that CO2 sorption capacity decreased after impregnation. Due to lack of strait trends in CO2 sorption capacity decrease, the results were closely analyzed to find the reason for the inconsistencies. It was revealed that different amines represent different affinities for CO2 and that the size and structure of impregnating factor has influence on the CO2 sorption capacity of impregnated material. The character of a support was also noticeable as well for impregnation results as for the affinity to CO2. The influence of amine concentration used was investigated along with the comparison on how the theoretical percentage of the impregnation on the support influenced the results. The reaction mechanism of tertiary amine was taken into consideration in connection to no presence of water vapor during the experiments. Key findings were described in the work and provide a strong basis for further studies on CO2 adsorption on amine-impregnated support.

Hard coal as a potential low-cost adsorbent for removal of 4-chlorophenol from water.

The potential use of raw hard coals as low-cost adsorbents for the removal of 4-chlorophenol (4-CP) from aqueous solutions was examined. The effect of experimental parameters such as the pH and salt presence was evaluated. The kinetic studies showed the equilibrium time was found to be 2 h for all of the adsorbents and that the adsorption process followed the pseudo-second order kinetic model. The adsorption isotherms of the 4-CP on the hard coals were fitted to the Langmuir, Freundlich, Langmuir-Freundlich, Sips and Redlich-Peterson equations. Based on the results obtained, hard coals appear to be a promising adsorbent for the removal of some hazardous water pollutants, like 4-CP and related compounds.