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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.
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Nanobioremediation of heavy metals using microorganisms
(Elsevier BV, 2025-09)
HESAM, KAMYAB
;
Shreeshivadasan Chelliapan
;
Elham Khalili
;
ZULETA MEDIAVILLA, DIANA PATRICIA
;
KHORAMI, MAJID
Heavy metals (HMs) in soil are a big threat to environmental and agricultural sustainability. This review discusses the development of the nanobioremediation paradigm (an approach combining nanotechnology and microbiological processes) for the treatment of HM toxicity. Recent advances in nanoparticle (NP)-based approaches to their ability to improve microbial detoxification methods, such as adsorption, redox transformation, and enzyme activation forms of microbial detoxification are discussed. Key findings suggest that many engineered NPs (e.g., zero-valent iron, biogenic metal oxides) can enhance HM immobilization efficiencies and contour microbial performances and functions of the soil microbiome. Still, there are areas of uncertainty regarding NP-microbe-soil interactions, long-term ecotoxicological effects, and applicability at the field level that are critical to be discussed. Future research directions are advised to focus on the eco-designed NPs, optimizing microbial consortia specific to the soil, and interdisciplinary frameworks linking the laboratory methods and materials to the real-world applications.
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High-performance supercapacitors based on NiMn layered double hydroxides/Ni3S2 nanocomposite
(Elsevier BV, 2025-04-01)
Yezeng He
;
Xinfeng Liu
;
Ke He
;
Hesam Kamyab
;
Lalitha Gnanasekaran
Layered double hydroxide (LDH), an emerging electroactive material, receives significant attention in storage and energy conversion area due to its excellent ion insertion and exchange capacity. Transition metal sulfides with multiple oxidation states and redox reactions maintain high-power density. In this research, NiMn-LDH on transition metal sulfides M − S (M = Ni, Co, Mn, Fe) are synthesized. Of these, NiMn-LDH/Ni3S2 demonstrates excellent electrochemical efficiency. In the three-electrode system, NiMn-LDH/Ni3S2 electrode achieves high specific capacitance of 2028.38 mF cm⁻2 at 1 mA cm⁻2 and excellent cycling stability of 69.53 % retention after 5000 cycles at 10 mA cm⁻2. The device consisting of activated carbon and NiMn-LDH/Ni3S2 exhibits a remarkable energy density of 63.06 Wh kg⁻1 at a power density of 1599.94 W kg⁻1. The NiMn-LDH/Ni3S2 electrode demonstrates an effective pseudo-capacitance performance and holds a great promise for electrodes in capacitive energy storage devices. © 2025 Elsevier B.V.
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Effective removal of organic substances and nutrients using microgranular sludge in a sequential batch reactor
(Elsevier BV, 2024-03)
Thilagavathi Arumugham
;
Adhi Yuniarto
;
Norhayati Abdullah
;
Ali Yuzir
;
Tejraj M. Aminabhavi
Aerobic microgranular sludge was cultivated in a sequential batch reactor (SBR) under varying aerobic and anaerobic conditions with low dissolved oxygen levels to remove the nutrients and organic substances. The study employed synthetic wastewater from an actual wastewater treatment center (Kuala Lumpur, Malaysia) as the medium and initial substrate for SBR using seed sludge as the inoculum. The aerobic microgranular sludge occurred gradually over 140 days, transitioning from anaerobic to aerobic conditions. By day 105, granules with a diameter >0.3 mm constituted approximately 50 % of the total biomass, reaching the minimum threshold of 80 % biomass upon implementation of the aeration. The cultivated aerobic microgranular sludge exhibited 1.8 g/L of mixed liquor volatile suspended solids (MLVSS) and 85.11 mL/g of sludge volume index (SVI), effectively achieving low effluent concentrations of nitrogen (ammonium, phosphate, nitrate, nitrite) and chemical oxygen demand (COD). Nitrification and denitrification processes were observed with average removal efficiencies of 30.24 % for COD, 15.86 % for ammonium nitrogen, and 7.38 % for phosphate. Nitrospira genes enhanced nitrification, while Denitratisoma organisms were primarily responsible for the denitrification. A decrease in Candidatus Accumulibacter and Candidatus Competibacter led to poor phosphorus removal. Overall, the study suggests that small-sized granules demonstrate comparable efficacy to aerobic granular sludge in removing carbon, nitrogen, and phosphorus with aerobic microgranular sludge showing the potential for effective nutrient removal in wastewater treatment over extended periods.
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Controllable synthesis of nanostructured flower-like cadmium sulfides for photocatalytic degradation of methyl orange under different light sources
(Elsevier BV, 2024-03)
Akbar Hojjati-Najafabadi
;
Elahe Farahbakhsh
;
Golnaz Gholamalian
;
Peizhong Feng
;
Fatemeh Davar
This study focuses on the synthesis and characterization of cadmium sulfide nanostructures by coprecipitation method. The materials are characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared, and Raman spectroscopy. The bandgap of the nanostructures was calculated under different conditions ranged between 2.8 and 2.4 eV and the materials have flower-like morphology in a cubic crystal system. Photocatalytic degradation of methyl orange dye was investigated under different radiation sources (sunlight, ultraviolet light, xenon light, and sunlight simulator). The effect of pH, initial dye concentration, and photocatalyst concentration on dye degradation was examined to show good degradation performance upon exposure to sunlight, UV light and visible light radiation. The results showed that by reducing the pH, degradation was improved, showing good performance at pH 3 with 85 % within 90 min. In addition, the optimal conditions for dye degradation were observed at concentration of 10 mg, methyl orange dye initial concentration of 10 g/L, and pH of 3. A 100 % degradation of methyl orange dye occurred in 90 min of visible light radiation, suggesting the potentiality of cadmium sulfide nanostructures under the effect of UV irradiation for cleaner production and complete elimination of the dye from polluted water sources, thus contributing to environmental enhancement.

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