CRIS

Permanent URI for this communityhttps://cris.ute.edu.ec/handle/123456789/1

Browse

Search Results

Now showing 1 - 8 of 8

Some of the metrics are blocked by your
consent settings
Multifunctional silver nanoparticles-based composites for SERS detection and photocatalytic degradation of micro- and/or nano-plastics
(Elsevier BV, 2026-04)
Nguyễn Hoàng Ly
;
HESAM, KAMYAB
;
Yasser Vasseghian
;
Sang-Woo Joo
Micro- and/or nano-plastics (MNPs) pose an emerging environmental issue due to their widespread presence in aquatic habitats, persistence in the environment, and potential toxic effects on ecosystems and public health. Silver nanoparticles (AgNPs) are well-known not only as plasmonic materials but also as mediators of photocatalysis, which is one of the most promising tools for identifying and degrading MNPs. This review covers recent advances in surface-enhanced Raman scattering (SERS) detection and the photocatalytic degradation of common plastics (e.g., polystyrene, polypropylene, polyvinyl chloride, etc.) using multifunctional AgNPs-based composites. These SERS substrates can detect MNPs in contaminated environmental water with consistent signals and high sensitivity. Notably, upon irradiation, these composites produce reactive oxygen species, triggering chain reactions that break down polymer chains into new compounds. Although AgNPs-based composites are stable, their photocatalytic efficiency is often limited by poor solar spectrum utilization, mass transfer resistance, and electron-hole recombination, leading to lower degradation rates and variable results. Some research highlights the ongoing need to improve photocatalyst design, reactor setups, and assessment methods for degradation. Additionally, the possible formation of toxic intermediates raises safety concerns, underscoring the need for further studies on ecotoxicological effects. When combined with other treatment methods, AgNPs-based SERS detection and photocatalysis provide a promising approach for addressing MNPs and other emerging pollutants in water treatment.
Some of the metrics are blocked by your
consent settings
Design of FeCoNiSmNd-co-doped porous carbon catalysts from pulverized coal for radical and non-radical peroxymonosulfate activation in organic pollutant degradation
(Elsevier BV, 2025-11)
Zhen Wu
;
Lisheng Wang
;
Xiaohan Wang
;
Bin Zhao
;
Heliang Fan
Pulverized coal has a good specific surface area, surface activity, and adsorption properties, which can be utilized to construct new carbon materials. In this work, multi-rare-earth elements co-doped coal-based composite catalysts are synthesized using a pyrolysis carbonization route with pulverized coal as the carbon source. The performance for the catalytic activation of persulfate is investigated with TC as the representative contaminant. The results demonstrate that the porous carbon-based catalyst with uniform doping of transition metals and rare earth metals is prepared with a surface area equal to 654 m2/g. This coal-based catalyst has good degradation efficiencies for TC (95.7 %), RhB (100.0 %), MO (90.0 %), and MB (100.0 %) in 30 min, respectively. The MB and RhB could be entirely degraded within 20 and 10 min, respectively. The activation energy of the reaction system is 16.21 kJ/mol. According to the free radical quenching reaction, the degradation of active compounds of tetracycline (TC) is calculated, which showed that O2•−(39.1 %), SO4•− (27.1 %), 1O2 (22.4 %) and •OH (15.6 %) all played important roles during the degradation of TC. The catalyst retains 94.5 % of its degradation efficiency after four cycles of use. The degradation efficiency and reaction rate constants of the system to degrade TC in lake water, tap water and seawater all increased due to the effect of Cl-, from 89.2 % and 0.2126 min−1 to 97.0 % and 0.3466 min−1, respectively, which showed the catalysts used have a good adaptability with different water.
Some of the metrics are blocked by your
consent settings
Photocatalytic CO2 conversions on copper nanoparticles investigated by Raman spectral changes using convolutional neural networks
(Elsevier BV, 2025-10)
Heung Seok Lee
;
Jaerin Choi
;
Jin Yong Lee
;
Ji Eun An
;
Thi Huong Vu
A convolutional neural network (CNN) deep learning process is employed to analyze in situ Raman scattering data for CO2 capture and its photocatalytic conversions onto copper sulfide hollow nanospheres (CuSHNSs) and copper nanocubes (CuNCs) in microalgae solution of Spirulina maxima. Raman spectra under visible light at 633 nm in a microfluidic solution provided representative vibrational marker bands of Cdouble bondO features at ∼2100 cm−1 and CH2/CH3 bending vibrations at ∼1400 cm−1 that are correlated with CO2 reduction products of carbon monoxide (C1) and multi‑carbon species such as propanol (C3), butanol (C4), respectively. Accumulated Raman spectra were trained and analyzed to estimate photocatalytic pathways using CNN algorithm. The presence of Spirulina maxima microalgae on the alteration of photocatalytic processes is studied by analyzing collective Raman spectral changes. The main observation is that strong CO peaks in Raman spectra of CO2 adsorbed by CuNCs almost disappeared after treatment with microalgae, whereas their intensities were slightly increased in case of CuSHNS. The CNN deep learning process for Raman spectra was effective to differentiate photocatalytic mechanisms of CO2 conversion onto nanoparticle surfaces.
Some of the metrics are blocked by your
consent settings
Tailoring high-entropy alloys for cutting-edge hydrogen evolution electrocatalysis
(Elsevier BV, 2025-12)
Akbar Hojjati-Najafabadi
;
Reza Behmadi
;
Yezeng He
;
HESAM, KAMYAB
;
Yasser Vasseghian
This paper provides a general overview of high-entropy alloys (HEAs) as future electrocatalysts for the hydrogen evolution reaction (HER). Growing energy demands worldwide and the need to mitigate climate change have placed attention on the efficient, sustainable production of hydrogen through electrochemical water splitting. Traditional noble-metal electrocatalysts such as platinum (Pt) possess excellent HER activity but are burdened by exorbitantly inhibitive cost, scarcity, and poisoning sensitivity. High-entropy alloys that consist of five or more major components in nearly equimolar proportions offer a paradigmatic solution due to their unique structural and electronic properties. High configurational entropy, lattice distortion, sluggish diffusion, and synergistic "cocktail" effects, in combination, enhance the catalytic activity of these alloys. Improved synthesis techniques of HEAs in nanoparticle, nanowire, and porous network forms have been discovered to exhibit high HER activity with low overpotentials and long-term durability. This review critically explores the fundamental principles of HER, the design principles of HEA electrocatalysts, and their applications in catalysis, with special focus on directions for future research to realize their full potential.
Some of the metrics are blocked by your
consent settings
Hybrid Photocatalytic Porphyrin-Functionalized UiO-66/BiVO4 for Enhanced CO2 Reduction Using Photosystem II
(Wiley, 2025-09-04)
Van Duc Bui
;
Thi Huong Vu
;
Thi Phuong Anh Tran
;
Le Minh Khoa Nguyen
;
HESAM, KAMYAB
Harnessing abundant solar energy for sustainable fuel production offers one of the most encouraging strategies to mitigate CO2 emissions. The discovery of novel and efficient photocatalysts to enhance photocatalytic CO2 reduction is important for converting solar energy to fuel. Porphyrin‐functionalized UiO‐66 on a BiVO4 semiconductor is introduced to convert CO2 via photoreactions. Here, the solar‐driven production of carbonaceous feedstocks is reported using a novel photocatalytic material S‐scheme UiO‐66‐TCPP‐BiVO4 heterojunction coupled with the photosystem II (PSII) in a microalgae. Coupling PSII with synthetic catalysts improves the efficiency of light‐harvesting and the CO2 reduction reaction (CO2RR). Electrochemical impedance spectroscopy, transient photocurrent response, photoluminescence lifetime, X‐ray photoelectron spectrometer, transmission electron microscope (TEM), X‐ray diffraction (XRD), and electron spin resonance measurements are conducted to determine the complex structural and electronic properties and the photocatalytic performance. In situ Fourier‐transform infrared spectra provide the CO2RR processes, revealing the mechanism by detailing intermediate formation and energy pathways.
Some of the metrics are blocked by your
consent settings
A novel photocatalytic degradation of mixed dye through chemically synthesized ZnO/Fe2O3 nanocomposite
(Springer Science and Business Media LLC, 2024-06-07)
Utaiyachandran Manojkumar
;
Durairaj Kaliannan
;
Balamuralikrishnan Balasubramanian
;
Hesam Kamyab
;
Yasser Vasseghian
This study reported the synthesis and assessment of zinc oxide/iron oxide (ZnO/Fe2O3) nanocomposite as photocatalysts for the degradation of a mixture of methylene red and methylene blue dyes. X-ray diffraction analysis confirms that the crystallite of zinc oxide (ZnO) has a hexagonal wurtzite phase and iron oxide (Fe2O3) has a rhombohedral phase. Fourier Transform Infra-Red spectrum confirms the presence of Zn–O vibration stretching at 428, 480 and 543 cm−1 stretching confirming Fe–O bond formation. Scanning Electron Microscope images exhibited a diverse size and shape of the nanocomposites. The ZnO-90%/Fe2O3-10% and ZnO-10%/Fe2O3-90% nanocomposites reveal good photocatalytic activity with reaction rate constants of 1.5 × 10−2 and 0.66 × 10−2; and 1.3 × 10−2 and 0.60 × 10−2 for methylene blue and methyl red dye respectively. The results revealed that the synthesized ZnO/Fe2O3 nanocomposite is the best catalyst for dye degradation and can be used for industrial applications in future.
Some of the metrics are blocked by your
consent settings
Appraisal of the potential of endophytic bacterium Bacillus amyloliquefaciens from Alternanthera philoxeroides: A triple approach to heavy metal bioremediation, diesel biodegradation, and biosurfactant production
(Elsevier BV, 2024-10)
Soma Biswas
;
Saranya Jayaram
;
Indhu Philip
;
Balamuralikrishnan Balasubramanian
;
Manikantan Pappuswamy
Endophytic microbes have been associated with many positive traits due to their endurance mechanisms. The current study was designed at exploring the potential of the endophytic bacterium Bacillus amyloliquefaciens MEBAphL4 isolated from Alternanthera philoxeroides for biosurfactant production and bioremediation efficiency. This endophyte, isolated from the polluted Madiwala lake in Bangalore, displayed elevated resistance to Cr and Pb till 2000 mg/L. The metal removal efficiency was found to be higher for Cr (25.7 %) at pH 6 and for Pb (92.3 %) at pH 9. Further, the present study also describes biosurfactant production with good emulsification ability (E24-52 %) and stability over a range of pH (8−12), temperature (20–40°C) and salinity (5–15 %). Biosurfactant production was enhanced 1.18-fold using the Response Surface Methodology approach and characterised by Fourier Transformation Infra-red Spectroscopy and Ultra-Performance Liquid Chromatography- Mass Spectrometry showing the presence of lipopeptides, fengycin, iturin and surfactin of molecular weights 1463.65, 1043.44 and 1012.56 Da respectively. The potential application of the biosurfactant in degrading various hydrocarbons was evaluated, demonstrating its effectiveness in bioremediation of oil-contaminated sites. Specifically, diesel biodegradation was measured at 56.46±0.95 %. These findings underscore the potential of B. amyloliquefaciens in environmental applications such as heavy metal biosorption and the bioremediation of contaminated sites, particularly those affected by oil spills and correlates to UN SDG6 of clean water and sanitation.
Some of the metrics are blocked by your
consent settings
Minimizing the polymer content of compressed transparent synthetic wood from renewable biomass sources: A comparative life cycle assessment
(Elsevier BV, 2024-07)
Jiamin Wu
;
Yang Wang
;
Yasser Vasseghian
;
Yingkuan Du
;
Hesam Kamyab
Transparent wood derived from renewable biomass resources has an enormous potential for utilizing in constructions, electrons devices, energy storage, etc. However, due to its high polymer content, the currently described transparent wood could not be developed in a sustainable manner. Herein, a feasible strategy for synthesizing compressed transparent wood was proposed to minimize the content of polymerized poly(methyl methacrylate) in composites, involving the poly(methyl methacrylate) partial-filling into the delignified wood and densification. This synthesis method prompted a substantial reduction of poly(methyl methacrylate) content (58.8%) in the obtained compressed transparent wood contrasted with the typical transparent wood (91.8% poly(methyl methacrylate) content). Besides, an ideal optical transmittance of 77.9% with 0.4 mm thickness and an optical haze of 49.2% with 0.7 mm thickness at 800 nm wavelength were achieved. Also, the improved tensile strength and flexural strength of compressed transparent wood were up to 85.0 MPa and 145.3 MPa, respectively. Additionally, a comparative life cycle assessment was conducted to assess the environmental impacts. The total environmental impact score was separately reduced by 23%, and 28% compared to the typical transparent wood and poly(methyl methacrylate) polymer, suggesting the feasibility of sustainable manufacture of transparent wood materials by decreasing polymer content. The compressed transparent wood also showed much lower thermal conductivities (0.28–0.31 W/mk) than glass and contributed to offering uniform illumination.

CRIS

Browse

Filters

Settings

Sort By

Results per page

Search Results