In this study, we developed a thermal storage medium comprising porous activated carbon filled with organic phase-change materials (PCMs) that utilizes the latent heat of phase-change to absorb heat during heating and release heat during cooling. For the activated carbon, we used both charcoal-based powdered activated carbon (250–350 mesh) and granular activated carbon. The organic phase-change materials used in the experiments were dodecane, tridecane, tetradecane, and pentadecane. Material properties such as thermal conductivity, latent heat, and melting temperature range were evaluated experimentally and theoretically, with the results observed to be consistent. The cyclic thermal performance of the proposed medium was also evaluated. Notably, filling the activated carbon with a mixture of organic PCMs resulted in the highest temperature-moderating effect. The procedure and results presented in this study are expected to aid in further improvement in the performance of thermal storage media containing PCM where stable temperatures are required, including building heating and cooling.

Fine and ultrafine particulate matter are consequences of air pollution in industrialized nations. The use of natural materials for filters produces fewer side effects for humans and the environment, and due to their structural characteristics, they have the potential to effectively filter out fine particles. In this study, we developed an indoor, fine-dust removal filter using Hanji, a traditional Korean paper made from natural materials derived from mulberry trees. We impregnated activated carbon (AC) into the Hanji filter and conducted air permeability and efficiency experiments to determine the improvement in indoor air quality. The Hanji filter showed a removal efficiency of 80.4% within the first minute and 99.1% efficiency by the 38th minute, maintaining an efficiency of >99% thereafter. The dust removal efficiency of the AC-embedded Hanji filter proved superior. The dust adhesion was ~20 g/m². An AC-embedded Hanji filter has the potential to remove not only fine dust but also volatile substances. The use of natural filters is both effective and sustainable.

A series of novel Mn_xFe_y@SiO₂ (x,y = 1–20%) nanocomposites were synthesized for the first time via the sol-gel/combustion method with different content of precursors (Mn and Fe acetate salts). The effect of precursor content and ratio on physicochemical properties were observed by various characterization methods. Moreover, Rhodamine B (RhB) was chosen as the target pollutant to test the performance of these nanocomposites under a photocatalytic Fenton-like reaction. The results showed that the nanocomposite morphology improved by increasing Fe and Mn content. In this study, interesting behavior was observed in BET results which were different from the fact that increasing metal content can decrease the surface area. This study revealed that one metal could be more critical in controlling the properties than another. Moreover, the precursor ratio appears to have a more tangible effect on the surface area than the effect of precursor content. Among all synthesized nanocomposites, Mn₁Fe₅@SiO₂ showed the highest surface area of 654.95 m²/g. At optimum batch conditions (temp = 25 °C, catalyst dosage = 1 g L⁻¹, H₂O₂ = 75 mmolL⁻¹, and initial RhB concentration = 50 mg L⁻¹), complete removal (simultaneous adsorption/degradation) occurred using Mn₁Fe₅@SiO₂ at neutral pH. This study showed that the designed nanomaterial could be used as a dual functional adsorbent/photocatalyst in different environmental applications.