Search

This study explores the adsorption potential of hydrothermally treated waste derived algal biomass for removing methylene blue (MB) dye. Synthesizing a modified hydrochar through hydrothermal carbonization (150°C, 35 bar) followed by NaOH modification, we observed enhanced thermal stability and distinctive chemical changes. Optimal conditions were determined at pH 6 and 1 h contact time. Soluble salts with cations were identified as impacting adsorption efficiency, with increased interference for higher cation charges. Thermodynamic parameters (ΔG, ΔH, and ΔS) indicated a spontaneous and exothermic process, the calculated values (−5.417 to −6.907 kJ mol−1, −29.0 kJ mol−1, −73.8 J K−1 mol−1) aligned with this behavior. Adsorption isotherms favored the Freundlich model, revealing heterogeneous multilayer adsorption, with a maximum capacity of 97%. Kinetic studies supported the pseudo‐first‐order model. This detailed exploration provides insights into thermodynamics, kinetics, and the impact of adsorption parameters on MB removal, emphasizing the practicality of alkaline‐modified hydrochar as an effective, sustainable adsorbent. [ABSTRACT FROM AUTHOR]

The study aims to characterize the structural features of Jordanian tar sand using analytical techniques including (FTIR, ultimate and proximate analysis, TGA, XRD, and XRF). The tar sand shows a low content of volatile matter (bitumen) with significant nitrogen content. The bitumen contains a high proportion of aliphatic hydrocarbons of which high content of it attached to oxygen atom. The minerals were mainly quartz and low concentration of carbonate with noticeable content of sulfite and potassium oxide from XRF. The recovery of bitumen was evaluated using three different extraction techniques: solvent extraction methods (ultrasound-assisted extraction, non-aqueous extraction) and thermal pyrolysis using the Fischer assay apparatus. The non-aqueous solvent extraction method gave the highest bitumen recovery using toluene as a solvent; however, the high-temperature Fischer assay method provided a low recovery. The extracted bitumen under the optimum condition was characterized using NMR, elemental analysis, and GC-MS analysis. The oil products from tar sand showed a high concentration of oxygen and noticeable concentration of sulfur atoms. The 1H-NMR revealed a high content of aliphatic hydrocarbons in good agreement with raw tar sand characteristics. The identified compounds in the GC-MS where mainly substituted with oxygen atom in the form of alcohols and ethers. [ABSTRACT FROM AUTHOR]

Jordanian kaolinite was treated with two phosphate modifiers: sodium polyphosphate (MK 1) and sodium hexametaphosphate (MK 2). Both raw and modified kaolinites were characterised by XRD and FTIR techniques. The adsorption behaviour of Th(IV) and U(VI) ions onto the two modified kaolinites were studied as a function of dosage, contact time, pH and temperature. The adsorption isotherm of both metal ions onto modified kaolinite was investigated using Langmuir, Freundlich and Dubinin–Radushkevich (D-R) models, which fits better to the Langmuir model. MK 1 kaolinite showed higher metal ion uptake than MK 2 kaolinite for both ions. The metal ion uptake of Th(IV) ions on both modified kaolinites was significantly higher than that of U(VI) ions. The % adsorption efficiency (73.8 and 69.0%) of Th(IV) ions on MK 1 and MK 2 was significantly higher than that of U(VI) ions (35.0 and 13.3%). The adsorption capacities for Th(IV) (188.7 and 9.6 (mg/g)) and U(VI) (53.5 and 15.3(mg/g)) were improved when MK 1 and MK 2 kaolinites were used at 25°C. The thermodynamic studies indicated that the removal of U(VI) and Th(IV) ions using both modified kaolinites is spontaneous and favourable at higher temperatures. The positive entropy values indicated that the adsorption process increased the disorder of the system. The kinetic study had indicated that the pseudo-second-order kinetic model fit the adsorption data, suggesting a chemisorption nature of the adsorption process. Binary system experiments under optimised conditions showed higher removal of Th(IV) ions compared to U(VI) ions. The desorption study showed that the elution of both metal ions increased as the concentration of HNO3 increased. Both the modified kaolinites were regenerated three times, a slight reduction of their adsorption efficiency was observed, and the presence of interferences has the same effect. [ABSTRACT FROM AUTHOR]

Oil shale is a raw material that is considered to be an alternative fossil fuels and it is widely used in producing energy and chemicals. Oil shale bitumen identification are not widely described in literature. This article tackles the structural elucidation of oil shale bitumen using gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) spectroscopy with a short sample preparation step, based on ultrasonic-assisted liquid extraction. The ultrasonic-assisted extraction was examined in terms of solvent type and volume, sample size, sonication time and temperatures. A bitumen recovery of 17.7 wt% dmmf (dry-mineral-matter-free) was achieved when 0.50 g of shale was mixed with 20 mL THF and sonicated for 10 min at ultrasonic power of 120 W at 45°C. GC-MS of the bitumen showed high polar oxygenated compounds with more than 20 wt% being esters and ethers. Small concentrations of thiols and amides have been also found. The structural identification of bitumen was carried out using 1H-NMR and 13C-NMR and the results showed highly aliphatic character bitumen, consisting of aromatic, paraffinic, naphthenic and olefinic hydrogen and carbon atoms. These results suggested that ultrasonic solvent extraction could be an efficient and environment-friendly method for obtaining of bitumen from oil shale. [ABSTRACT FROM AUTHOR]

Few comparisons have been made between low-aromaticity marine and lacustrine oil shales and their kerogens, because the reliability of structural analyses has been limited by a reliance on only one method of kerogen isolation, HCl-HF. Therefore, a detailed analysis by 13C NMR and X-ray photoelectron spectroscopy (XPS) was made for Attrat marine oil shale (Jordan) and Colorado (Green River) lacustrine oil shale (USA) and their NaOH-HCl kerogens. Some differences between oil shales and their kerogens were noted, but many structural features were considered to be true characteristics of the organic matter. The results emphasise the importance of comparing the analyses of kerogens isolated by different methods to ensure that features of the organic matter are not an artefact of the method of kerogen isolation. For both oil shales, the predominantly aliphatic character of the organic part was confirmed and the long average chain length of the aliphatic hydrocarbons was established. All shales and their kerogens showed a small cluster size for the aromatic rings. The elemental analysis obtained by XPS, compared with the bulk elemental analysis, indicated major differences between the near-surface region sampled by XPS and the bulk. The organic S was determined to be aliphatic and aromatic S with possibly small amounts of sulfoxide. Most of the N was pyrrolic with smaller amounts in pyridinic or quaternary form. Nearly all of the surface organic C in both kerogens was bonded to C and H. Two major forms of organic O were distinguishable. A good correlation between the proportion of aliphatic S and pyrolysis reactivity is suggested. This paper studies the comparison between low-aromaticity marine (Attrat-Jordan) and lacustrine (Colorado-USA) oil shales and their kerogens. Kerogens were extracted using NaOH-HCl method. The characterisations were performed using elemental analysis, Rock Eval, 13C NMR, and XPS. This work reveals some differences in the organic structure between the two kerogens. [ABSTRACT FROM AUTHOR]

Oil shales from two different continents (Australia and North America) of different ages (100 and 40 million years) and origins (one marine, one lacustrine) have been reacted in the range 355–425 °C under H 2 or N 2 for 1 or 5 h with or without the addition of catalyst. The shales differed in S content, and the nature of the mineral matter, but both had high atomic H/C ratios. The overall reactivity of the two shales was similar and high yields of soluble products could be obtained under relatively mild conditions with only small CO 2 yields, but the temperature dependence of reactivity and the effect of potential catalysts differed markedly. Increasing the temperature and time led to increases in conversion but of different extents. Substituting H 2 for N 2 led to a large increase to conversion for the lower-atomic-H/C ratio marine oil shale. The CH 2 Cl 2 solubles from the marine oil shale showed a larger range of compounds than those from the lacustrine oil shale which resembled the CH 2 Cl 2 solubles from torbanite, a coal-like material derived from lacustrine algae. [ABSTRACT FROM AUTHOR]

Four oil shales from different locations and origins have been reacted in a flow-through system (425 °C, with N 2 or H 2 as sweep gases at 1 atm pressure) with a view to more closely simulating a practical process for oil shale conversion than can be achieved with a sealed autoclave system. It was observed that there was no general correlation between the yields in the two systems, nor was there a general correlation between the amount of condensate and the amount of volatiles obtained by thermogravimetric analysis. For all four oil shales, the condensate gave more complex gas chromatography–mass spectrometry total ion chromatograms (GC–MS TICs) than the CH 2 Cl 2 -solubles from sealed autoclave reactions. Surprisingly, the products from one of the Jordanian oil shales, Yarmouk, and an Australian Julia Creek oil shale were remarkably similar. The product from the lacustrine Colorado oil shale was much more similar to that from a lacustrine algal coal (torbanite) than to those from marine oil shales. The differences in yields and product characteristics between sealed autoclave and flow-through reactions suggest that yields and product distributions obtained from sealed autoclave reactions should be treated with caution. [ABSTRACT FROM AUTHOR]

The increase in energy demand, especially in Jordan, has encouraged researchers to consider alternative sources of energy, such as biofuel production from agricultural waste. For this study, Jordanian corn leaf waste was characterized by ultimate and proximate analysis, TGA, FTIR and solid state 13C NMR. The waste showed high volatile matter, high atomic H/C ratio and high O content. The corn leaf waste contained 32.1 wt% cellulose, 18.1 wt% hemicelluloses and 11.9 wt% lignin. The FTIR and 13C NMR spectrums showed high concentrations of aliphatic and carbonyl carbon. The corn leaf waste was pyrolysed in a temperature range of 300–450 °C under a constant flow rate of nitrogen. Higher oil yield was obtained at pyrolysis temperature of 450 °C. The gas yield and higher heating value of the product increased as the temperature increased, whereas the water content decreased. The biofuels were rich in carbon and had a high oxygen content, which decreased as the temperature increased. The 1H NMR confirmed the markedly aliphatic character of the biofuel. The GC-MS for the biofuel indicated the presence of hydrocarbon series, large amounts of oxygenated compounds and a few nitrogen and sulfur compounds. The simulated distillation showed a high proportion of diesel fraction (57–73%). Image 1 • Detailed structural characterization of corn leaf waste is given. • The corn leaf waste was pyrolysed in 300–450 °C under nitrogen. • The biofuel contained only 8–18% aromatic protons. • Biofuel O content fell from 27% (<300 °C biofuel) to 18% (400–450 °C biofuel). • Important identified biofuel compounds: phenols, neophytadiene and acids. [ABSTRACT FROM AUTHOR]

Purpose: To study the adsorption of dye (E120) from aqueous solution onto activated carbon. Method: Factors influencing adsorption were examined and optimized. Three adsorption isotherm models (Langmuir, Freundlich and Temkin) were investigated. Agitation time was set at 72 hours, E120 dye concentration at 10 – 80 mg/L, pH at 7, temperature at 25 oC and mass at 125 mg. Results: Adsorption of E120 dye onto activated carbon was enhanced by decreasing the mass of activated carbon, pH and ionic strength of the solution and by increasing the temperature. Under optimal conditions, the maximum adsorption capacity of activated carbon for E120 dye was 10.1 mg/g at 30 oC. The model parameters were 0.307 L/mg (KL), 10.1 mg/g (qm), 0.9491 (R2) for the Langmuir isotherm; 2.98 (n), 0.445 mg/g (Kf), and 0.6592 (R2) for Freundlich isotherm; and 4.59 mg/L (A), 2.23 J/mol (B), and 0.5914 (R2) for Temkin isotherm. Thermodynamic studies indicate that the adsorption of E120 dye onto activated carbon is an endothermic process with an adsorption enthalpy (ΔH) of 8.7 KJ/mol. The positive values for ΔG indicate that adsorption was non-spontaneous. The kinetic study of E120 dye adsorption showed that the adsorption process obeyed pseudo-second order kinetics. Conclusion: Commercially available activated carbon, in terms of its physical and chemical characteristics, is a superior adsorbent to other adsorbents mentioned in the literature for removal of toxic dye E120 from aqueous solutions at a high removal capacity. [ABSTRACT FROM AUTHOR]

The use of catalysts to promote sorbent regeneration is currently considered an effective method to reduce the energy required in CO 2 capture processes. Aiming at identifying stable and cost-effective catalysts with high CO 2 desorption efficiency, here we investigated the performance of fly ash (FA) during thermal regeneration of aqueous amine solutions. The desorption rate, cyclic capacity and heat duty of a CO 2 -saturated aqueous ethanolamine with the addition of FA were experimentally measured, and the results were compared with those obtained for the same solution without and with eight different catalysts. Experimental results showed that catalysts significantly improved the regeneration compared to the non-catalyzed system, and FA was the most efficient of these. Further studies of CO 2 desorption at different temperatures showed that FA provided desorption performance comparable to that of the non-catalyzed system at temperatures at least 5 °C higher and always significantly reduced the heat duty at the same temperature, especially at the beginning of the process. Finally, recycling tests demonstrated that FA had good stability and its catalytic efficiency remained high even after 20 cycles. In conclusion, FA could be considered a cost-effective catalyst for energy-efficient CO 2 capture, deserving further investigation to promote its application in industrial-scale plants. • Reuse of fly ash from industrial waste to catalyst for CCUS desorption process. • MEA regeneration at 88 °C with FA is more efficient than the non-catalyzed system. • Reduction in energy consumption by up to 54.1% compared to non-catalyzed system. [ABSTRACT FROM AUTHOR]