In the paper spent coffee grounds were used as a precursor to obtain activated carbons. The raw material was impregnated with phosphoric acid(V) at the different impregnations ratios: 0.5, 1, 1.5, 2. Carbonization was carried out according to two procedures differing in activation atmosphere (N₂ or CO₂). The obtained activated carbons were characterized on the basis of low-temperature nitrogen adsorption/desorption, thermal analysis, potentiometric titration method, X-ray diffraction, Raman spectroscopy and scanning electron microscopy. Carbons obtained according to procedure 2 (activation in CO₂) were characterized by better developed porosity, e.g. surface (S_BET to 720.9 m²/g) and pore volume (V_p to 0.334 cm³/g). All obtained carbons had surface acidic (mainly carboxyl) groups and exhibited the amorphous structure. The thermal analysis showed that the obtained materials were thermally stable up to the temperature ~ 420 °C.

Agricultural waste materials (strawberry seeds and pistachio shells) were used for preparation of activated carbons by two various methods. Chemical activation using acetic acid and physical activation with gaseous agents (carbon dioxide and water vapor) were chosen as mild and environmentally friendly methods. The effect of type of raw material, temperature, and activation agent on the porous structure characteristics of the materials was discussed applying various methods of analysis. The best obtained activated carbons were characterized by high values of specific surface area (555–685 m²/g). The Guinier analysis of small-angle X-ray scattering (SAXS) curves showed that a time of activation affects pore size. The samples activated using carbon dioxide were characterized mostly by the spherical morphology of pores. Adsorbents were utilized for removal of the model organic pollutants from the single- and multicomponent systems. The adsorption capacities for the 4-chloro-2-methyphenoxyacetic acid (MCPA) removal were equal to 1.43–1.56 mmol/g; however, for adsorbent from strawberry seeds it was much lower. Slight effect of crystal violet presence on the MCPA adsorption and inversely was noticed as a result of adsorption in different types of pores. For similar herbicides strong competition in capacity and adsorption rate was observed. For analysis of kinetic data various equations were used.

The present study focuses on the mechanism of swelling and evaluates interactions between solvents of different chemical characters (polar—ethanol, nonpolar—n-heptane) and commercially available porous Amberlite polymers (XAD4, XAD16, XAD7HP) by temperature-programmed desorption (TPD). The first two polymers are the product of copolymerization of styrene and divinylbenzene. Despite having the same chemical composition, they differ in pore size and volume. The Amberlite XAD7HP is composed of an acrylic matrix and has lower pore volume and specific surface area than XAD16 and XAD4. All three resins have the ability to swell, though the per cent of polymeric network expansion during this process varies depending on the solvent used (e.g. in tetraethyl orthosilicate, XAD4 and XAD16 spherical particles increase in volume by 20–30%, while XAD7HP particles can expand by more than 120%). The TPD experiment was performed in dynamic linear and quasistatic heating mode. Based on thermogravimetric data, the desorption energy of selected liquids and pore size distribution in the swollen state were estimated. The obtained results are discussed in terms of both mathematical modelling and low-temperature nitrogen adsorption–desorption experiment.

In the presented research, activated carbons from wheat bran were obtained as a result of pyrolysis and physical activation (CO₂ or/and steam). In addition, the obtained materials were subjected to additional modification with superheated steam using the microwave radiation as an energy source. The detailed materials characterization was performed using low-temperature nitrogen adsorption/desorption, Raman spectroscopy, X-ray diffraction, thermal analysis (TG), Boehm’s titration, point of zero charge (pH_pzc), scanning electron microscopy (SEM) and FT-IR/ATR methods. Moreover, the sorption capacity towards methylene blue (MB) was determined. The activated carbons were characterized with a well-developed surface and pore structure (S_BET = 339.6–594.0 m²/g; V_p = 0.157–0.356 cm³/g). Activation in the presence of steam and additional modification with microwave radiation resulted in much better development of the porous structure (S_BET = 600.4 m²/g; V_p = 0.380 cm³/g). The materials were shown to possess amorphous structure and thermal stability up to the temperatures of ~450–500 °C. They have good adsorption capacity towards MB varying from 150 mg/g to 241 mg/g depending on activation manner. The adsorption can be described by the pseudo-second order model (R² = 0.99) and fitted to the Langmuir isotherm.