The increasing demand for sustainable and efficient energy storage materials has led to significant research into utilizing waste biomass for producing activated carbons. This study investigates the impact of the structural properties of activated carbons derived from various lignocellulosic biomasses—barley straw, wheat straw, and wheat bran—on the electrochemical performance of supercapacitors. The Fourier Transform Infrared (FTIR) spectroscopy analysis reveals the presence of key functional groups and their transformations during carbonization and activation processes. The Raman spectra provide detailed insights into the structural features and defects in the carbon materials. The electrochemical tests indicate that the activated carbon’s specific capacitance and energy density are influenced by the biomass source. It is shown that the wheat-bran-based electrodes exhibit the highest performance. This research demonstrates the potential of waste-biomass-derived activated carbons as high-performance materials for energy storage applications, contributing to sustainable and efficient supercapacitor development.
The spatial arrangement, size distribution, and shape of internal pores in several archaeological ceramic vessels from the Akterek burial site at Zhambyl District of Almaty Region, Republic of Kazakhstan were studied using neutron tomography. The internal pores were segmented from the obtained neutron data and the porosity value for the ancient ceramic samples was calculated. Analysis of the structural tomography data showed that the ceramic materials contained a large number of relatively small pores, with an average diameter less than 1.5 mm, while some ceramic objects had larger pores or cavities exceeding 2 mm in diameter. In addition, there are differences in the morphological parameters of large and small pores. It was suggested that these large pores formed as a result of temperature changes during the firing of the pottery ceramics. The relative shifting of Raman peaks in the carbon group in amorphous carbon, as an indicator of the firing temperature of ceramic materials, confirms this assumption.
Wormlike micelles (WLMs) of surfactants are widely used as smart thickeners in various applications, including enhanced oil recovery. However, their thickening ability needs to be improved both at ambient and elevated temperatures. In the present paper, we propose to enhance the viscoelastic properties of surfactant solutions by incorporating carboxymethylated cellulose nanocrystals (CNCs). Upon addition of CNCs, dilute solutions of short WLMs acquire viscoelasticity and then transition into a viscoelastic solid state. This process is accompanied by an increase in the viscosity and storage modulus by up to five and four orders of magnitude, respectively. The observed effect of CNCs on the storage modulus and viscosity is greater than that of any of the previously studied WLM-CNC systems. It is attributed to the formation of a network of fibrillar-like aggregates composed of WLMs and CNCs, which was confirmed by cryo-TEM data. To our knowledge, such kind of aggregates have not been observed before. When CNCs are added to a transient network of long entangled WLMs, the viscoelastic solution transitions into a viscoelastic solid state, which results in an increase in the viscosity and storage modulus by up to two orders of magnitude. CNCs provide the WLM solution with greater resistance to heating, such that the storage modulus remains almost unchanged when the temperature increases from 20 to 70 °C. Moreover, a heat-induced gelation was observed. It was shown that higher concentrations of nanocrystals lower the critical gel temperature, indicating that they promote the gelation of the mixture. SANS data revealed that the local structures of both micelles and nanocrystals are preserved in the mixed system upon heating. According to ITC data, at room temperature, the interaction between surfactant ions and similarly charged nanocrystals is governed by both enthalpy and entropy, which suggests that hydrogen bonding plays a major role in this process, although hydrophobic interactions may also be involved. When the temperature increases to 60 °C, the aggregation becomes entropy-driven, indicating that hydrophobic interactions begin to dominate. The results obtained can expand the range of practical applications of WLMs as thickening agents, in particular, to higher-temperature conditions in deeper oil wells.
We studied the structural features in internal pores and mineral inclusions of several vessels from the Shubarat-1 archeological site in the Republic of Kazakhstan, dating to the late first millennium BC, using neutron tomography. Differences in the neutron attenuation coefficients of the constituent elements of pottery objects, as well as the high penetration capability of neutron tomography, make it possible to conduct non-destructive studies of rare ceramic vessels. By analyzing the three-dimensional tomography data, we can reconstruct the size and morphological parameters of internal pores and minerals. Based on these structural findings, we can clarify past pottery production processes.