Dan-Thuy Van-Pham

The growing demand for sustainable and low-carbon construction materials underscores the importance of developing cementitious composites (CCs) that utilize renewable waste-derived admixtures without sacrificing performance. This study examines the effects of nanocellulose fibers (NF) extracted from pineapple leaf waste– a largely untapped agricultural byproduct–on the mechanical, microstructural, and porosity characteristics of CCs containing Class-F fly ash. CC samples incorporating 0.0–2.0 wt.% NF were evaluated for compressive and flexural strengths, porosity, and microstructural evolution using FTIR, XRD, and SEM analyses. The results revealed that a small addition of 0.5 wt.% NF helped maintain hydration uniformity and retained about 90% of the control compressive strength (74.1 MPa → 66.7 MPa), while higher dosages caused substantial deterioration: compressive and flexural strengths decreased to 10.2 MPa and 2.3 MPa, respectively, corresponding to an approximately 86% reduction in strength and a 253% increase in porosity (10.44% → 36.85%). A strong inverse, nonlinear correlation between porosity and mechanical strength was identified, confirming porosity as the principal factor governing performance. Overall, pineapple leaf–derived NF serves as a promising eco-efficient additive at low concentrations, but excessive dosages lead to agglomeration, hindered hydration, and pore coarsening, emphasizing the need for optimized dispersion and dosage control in bio based fiber–reinforced cement systems. These findings provide insights for the sustainable design of eco efficient CCs.

This study reports the green synthesis of ZnO nanoparticles using betel leaf (Piper betle) extract as a natural reducing and stabilizing agent. The synthesized ZnO nanoparticles were characterized by XRD, SEM, TEM, and UV-Vis spectroscopy, confirming their crystalline structure, spherical morphology, and an optical bandgap of 3.26 eV. The ZnO nanoparticles were then employed as the photoanode in dye-sensitized solar cells (DSSCs) using a natural dye extracted from mangosteen peel. Photovoltaic performance analysis revealed that DSSCs with a platinum (Pt) counter electrode exhibited a significantly higher efficiency (0.064%) compared to those using a carbon-based electrode (0.007%), demonstrating the superior catalytic activity of Pt in enhancing charge transport. These findings highlight the potential of ZnO nanoparticles synthesized via green methods for sustainable energy applications.

Poly(vinyl alcohol) (PVA) hydrogels are attractive wound-dressing materials due to their hydrophilicity, flexibility, and biocompatibility; however, achieving both high tensile strength (TS) and elongation at break (EAB) remains a major challenge. In this study, biodegradable PVA/starch (ST)/glycerol (GL) hydrogels were fabricated through stoichiometric control of hydroxyl molar ratios, guided by central composite design and freeze–thaw processing at −80 °C, to enhance hydrogen bonding without chemical crosslinkers. Synergistic interactions among PVA, ST, and GL enabled the hydrogels to achieve dual benchmarks of durability and flexibility. At GL/PV A = 0.1, PVA 4–10 wt%, and ST/PV A = 0.03–0.06, the hydrogels exhibited TS 12.5–24.4 MPa and EAB 270%–397%, exceeding favorable thresholds (TS >11.5 MPa; EAB >180 %). Additional attributes included high swelling capacity (>260 %), appropriate water vapor transmission (2660–3000 g/m ² /day), favorable biodegradability (80 % UVA/UVB blocking). Representative formulations highlighted the tunability of the system: one optimized for flexibility (EAB 390 %, TS 17.2 MPa) and another for UV protection (UV blocking >95 %). Microstructural and dynamic mechanical analyses confirmed that GL acted as a plasticizer, enhancing chain mobility, while ST modulated phase separation and stabilized the network. Overall, the findings demonstrate that stoichiometric control of hydroxyl molar ratios enables multifunctional PVA/ST/GL hydrogels to achieve a balance of strength, flexibility, and barrier properties, underscoring their potential as next-generation wound dressings.

This study addresses the mechanical strength–swelling trade-off in poly(vinyl alcohol) (PVA) hydrogels for wound care by adopting a crosslinker-free PVA/starch (ST) design. The objective was to statistically optimize composition for balanced tensile strength (TS), elongation at break (EAB), and swelling index (SI). Hydrogels were prepared by two freeze–thaw cycles at −80 °C, varying PVA (8.6–11.4 wt%) and ST/PVA (1.5–8.5 wt%), and modeled using a Central Composite Design. Properties were broadly tunable (TS 3.8–8.9 MPa; EAB 229–438%; SI 217–363%). The optimum 11.4 wt% PVA with 1.5 wt% ST/PVA achieved TS 7.85 MPa, EAB 387.2%, and SI 273%, in close agreement with predictions; scanning electron microscopy showed homogeneous ST dispersion and ductile fracture. Notably, mechanical strength approached chemically crosslinked benchmarks while eliminating toxic reagents. These results establish a green, scalable route to robust, absorbent PVA/ST membranes suited to dynamic wound sites and provide response-surface models as practical design rules for future functionalization.

Rapid technological advancement has increased energy consumption, environmental pollution, and climate change, necessitating sustainable sources of energy. Solar energy is appealing because it is renewable and has minimal environmental impact. However, the complex fabrication and high costs of conventional silicon solar cells have driven research into alternative technologies like perovskite solar cells (PSCs). This study investigates the use of electrospun nickel oxide (NiO)/carbon nanofibers as efficient hole-transporting layers in PSCs. NiO nanomaterials were synthesized via coprecipitation and integrated into polyvinyl alcohol nanofibers through electrospinning at an optimized concentration of 20 g/L, producing uniform nanofibers with mean (SD) diameter of 136 nm (20). The electrospun nanofibers were calcined to convert them into NiO/carbon nanofibers. The structural and chemical properties of nanofibers were characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared (FTIR) and Raman spectroscopy, thermogravimetric analysis, and photoluminescence spectroscopy. These NiO-based nanofibers were used as hole-conducting layers in constructing fluorine-doped tin oxide (FTO)/titanium dioxide peroxide P25(TiO2)/perovskite/NiO-carbon/FTO solar cells, achieving a maximum efficiency of 5.96%. This research shows the potential of NiO-based hole-conducting layers in enhancing PSC efficiency. Optimizing NiO concentration and electrospinning time can significantly improve the conductive properties and performance of PSCs.

This study synthesized a cellulose-based aerogel from bagasse with activated carbon and tested its effectiveness for crude oil spill remediation. Scanning electron microscopy (SEM) analyzed the morphology of bagasse fibers and their integration within the aerogel. Brunauer-Emmett-Teller (BET) analysis revealed a surface area of 34.53 m²/g, a micropore volume of 0.040 cm³/g, and 96.4% porosity. The Barrett-Joyner-Halenda (BJH) plot showed predominantly mesoporous features with an average pore diameter of 28.2 Å. X-ray diffraction (XRD) indicated a crystalline structure with a 76.4% crystallinity index. Fourier-transform infrared (FTIR) spectroscopy confirmed the presence of functional groups. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) showed excellent thermal stability. The aerogel exhibited an oil adsorption capacity of 12.78 grams per gram in seawater, demonstrating its effectiveness in oil spill cleanup.

This study evaluates the effectiveness of Trichoderma spp. in decomposing watermelon rind to produce bio-organic fertilizer. Response Surface Methodology (RSM) with Central Composite Design (CCD) was employed to optimize the cultivation conditions for Brassica juncea using the composted fertilizer. Results demonstrated that Trichoderma spp. significantly accelerated decomposition and improved fertilizer quality. Among the tested parameters, composting duration and fertilization rate significantly influenced plant growth, particularly leaf length and width, while microbial inoculant concentration had no notable effect. Microbial analysis confirmed that Coliform, E. coli, and Salmonella levels were below regulatory limits (ND 108/2017/ND-CP), with none detected in fertilizers produced with Trichoderma spp.. RSM optimization identified the optimal composting conditions as 18 days, 4 wt.% Trichoderma spp., and 50 v/v% fertilizer volume fraction. A high-accuracy mathematical model was developed to predict plant growth responses, effectively forecasting the impact of composting parameters on crop development. These findings highlight the potential of Trichoderma-based bio-organic fertilizers in sustainable agriculture.

The increasing amount of incineration ash raised significant environmental concerns, particularly regardingwaste disposal and pollution. To address these issues and promote sustainable development, this study explored the production of terrazzo tiles using a fine aggregate of waste incineration bottom ash (WIBA) and aternary binder of cement, fly ash, and hydrated lime. The findings revealed that the substitution of cement withhydrated lime at an optimal level (i.e., 1% by weight) enhanced the flexural and compressive strengths whilereducing the surface water absorption of the terrazzo tiles. The surface abrasion resistance remained relativelyunchanged due to the consistent use of the same surface material across samples. Observation of scanningelectron microscope images further confirmed the obtained engineering properties of the terrazzo tiles. As aresult, the terrazzo tiles met the Vietnamese National standard requirements for external use, further indicatingtheir suitability for various applications in construction. This study found that the terrazzo tiles produced usinga mixture of 13% cement, 1% hydrated lime, 10% fly ash, and 76% WIBA earned the lowest surface waterabsorption of 2.56% and the highest flexural and compressive strengths of 3.86 and 21.37 MPa, respectively.Whereas, the surface abrasion of the sample was recorded at 0.241 g/cm2, making it an optimal choice for practical use in construction.