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Pollution of water sources by pharmaceuticals has attracted attention. In this work, carbamazepine (CBZ), as a model pharmaceutical pollutant, was used to investigate its characteristics of adsorption from an aqueous solution. Flax shives and oat hulls, representing cellulosic materials of agricultural by-products, were characterized and used to develop hydrochars and steam activated hydrochars adsorbents. Hydrothermal treatment and steam activation significantly enhanced the CBZ adsorption capacity. The isotherms of CBZ adsorption by the steam activated hydrochars were experimentally investigated at various temperatures (20–40 °C) and satisfactorily simulated by the Sips model. The steam activated hydrochars of flax shives and oat hulls had higher maximum CBZ adsorption capacities of 293.5 and 162.6 mg/g than the respective hydrochars (75.3 and 81.8 mg/g) and raw materials (16.5 and 15.0 mg/g). Based on the isotherm modeling results, the site energy distribution of CBZ adsorption was further determined. The weighted means of site energy obtained at 40 °C (13.3–15.0 kJ/mol) were higher than those at 30 °C (11.2–13.4 kJ/mol) and 20 °C (7.7–8.0 kJ/mol), indicating higher adsorption affinity, thus more favorable adsorption. Furthermore, the thermodynamic parameters of CBZ adsorption were determined. The results indicated that the CBZ adsorption on hydrochars and steam activated hydrochars were endothermic and spontaneous. [ABSTRACT FROM AUTHOR]

In this work, the effects of different methods of activation on CO 2 adsorption performance of activated carbon were studied. Activated carbons were prepared from biochar, obtained from fast pyrolysis of white wood, using three different activation methods of steam activation, CO 2 activation and Potassium hydroxide (KOH) activation. CO 2 adsorption behavior of the produced activated carbons was studied in a fixed-bed reactor set-up at atmospheric pressure, temperature range of 25–65°C and inlet CO 2 concentration range of 10–30 mol% in He to determine the effects of the surface area, porosity and surface chemistry on adsorption capacity of the samples. Characterization of the micropore and mesopore texture was carried out using N 2 and CO 2 adsorption at 77 and 273 K, respectively. Central composite design was used to evaluate the combined effects of temperature and concentration of CO 2 on the adsorption behavior of the adsorbents. The KOH activated carbon with a total micropore volume of 0.62 cm 3 /g and surface area of 1400 m 2 /g had the highest CO 2 adsorption capacity of 1.8 mol/kg due to its microporous structure and high surface area under the optimized experimental conditions of 30 mol% CO 2 and 25°C. The performance of the adsorbents in multi-cyclic adsorption process was also assessed and the adsorption capacity of KOH and CO 2 activated carbons remained remarkably stable after 50 cycles with low temperature (160°C) regeneration. [ABSTRACT FROM AUTHOR]

Gasification of glucose in supercritical water with and without catalysts (NaOH and Ni based) was investigated at 400 °C and 500 °C with a residence time of 30 min. The products from glucose gasification without catalyst consist of ~ 8-17 wt.% gas, 21-24 wt.% solid, 9-16 wt.% acetone phase and 8-10 wt.% water phase. As expected, all the gas product yields increased by an increase in process temperature and higher water to biomass ratio benefits the yields of gas phase and water phase. For the experimental runs with catalysts, NaOH had the best activity for improving H2 formation, the H2 yield increased by 135% with NaOH compared to that for run without catalyst at 500 °C with water to biomass ratio of 3. At the same operating conditions, the presence of Ni/activated carbon (AC) contributed to 81% increase in H2 yield, followed by 62% with Ni/MgO, 60% with Ni/CeO2/Al2O3 and 52% with Ni/Al2O3. The net effect of Ni was studied by using activated carbon and Ni/AC at 500 °C with water to biomass ratio of 7 for 30 min. The results showed that the hydrogen production was further increased by 6.9% with activated carbon and 36.9% with Ni/AC. [ABSTRACT FROM AUTHOR]

Highlights: [•] Supercritical gasification of cellulose and pinewood was studied. [•] Ni/CeO2/Al2O3, dolomite, olivine and KOH were used as catalysts. [•] The effects of temperature and water to biomass ratio were studied. [•] H2 yield increased with an increase in temperature and/or water to biomass ratio. [•] KOH showed the best activity for H2 production from both precursors. [ABSTRACT FROM AUTHOR]