Green Chemical Technology

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Issue 2, Volume 2 – 6 articles

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A Cu-doped lead apatite sample denoted LK-99 was claimed to have room temperature ambient-pressure superconductivity and inspired extensive immediate experimental and theoretical works. However, either the crystal structure of apatite or copper-doped apatite is still illusive. In the purpose of contributing to a broad picture of “structure-property” relations, the crystal structures of four types natural apatite samples are obtained by utilizing single crystal X-ray diffraction (SXRD) rather than powder XRD firstly. Secondly copper-doped lead apatite has been synthesized via a three-step solid-state reaction method, and its crystal structure has been investigated by using SXRD, SEM/EDX, XPS and TEM.
It was found that the four natural apatite samples comprised one type of fluorapatite and three types of hydroxyapatite, all crystallized in the hexagonal system, P63/m space group. The refined crystal has been compared with prevailing structure models during the last 20 years. The crystal structure of our successfully synthesized copper-doped lead apatite contains three types of disordered atoms: O vacancy atoms, Pb/Cu split atoms and Pb/Cu co-occupying atoms. The topological analysis of the present structure model indicates that the it can be characterized by three single-shell clusters: P1 (1) (1@4), Pb1/Cu1 (1) (1@9), and Pb2 (1) (1@7).
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Open Access

Article

17 March 2025

Experimental Study on A Novel Organic/Inorganic Green Deep Eutectic Solvents: Thermophysical Properties, Thermal Stability, and Utilization in Nanofluids

In response to the performance limitations of traditional heat transfer fluids under extreme conditions, a series of organic/inorganic deep eutectic solvents (DES), composed of ethylene glycol and different types of acetates, have been developed, and their downstream thermophysical properties, as well as their potential applications in nanofluids, have been explored. It is found that the prepared DESs significantly broaden the liquid phase temperature range, which ranges from −14~196 °C to −40~201 °C. The initial decomposition temperature increases from 85 °C to 130 °C, and the peak decomposition rate shifts from 175 °C to 206 °C. Subsequently, nanofluids were prepared by employing the selected ethylene glycol: potassium acetate-5:1 DES with carbon nanotube as nanofiller. The results reveal that the thermal conductivity of the nanofluid could be increased by approximately 3% compared to the base fluid, and the specific heat capacity was enhanced by 7.5% with a photothermal conversion efficiency reaching up to 42.7%. These results highlight the promising thermal stability and heat transfer properties of ethylene glycol-acetate DESs. Moreover, the nanofluids prepared from those DESs as base fluids provide useful references for the development of novel, green, and high-efficiency energy transportation fluids.

Xiao Zhang
Xinqian Du
Jiahuan He
Pei Liu
Wenbo Huang
Guangyuan Liang
Haolin Gan
Jiateng Zhao
Changhui Liu*
Green Chem. Technol.
2025,
2
(2), 10003; 
DOI: 10.70322/gct.2025.10003
Open Access

Article

21 March 2025

Formation Mechanism and Structural Evolution of Mesophase Pitch via Phase Separation

Mesophase pitch is obtained through a two-stage treatment method combining stirring and non-stirring heat treatment of the catalytic cracking oil slurry. The structural evolution during the mesophase pitch forming process is analyzed using phase separation and testing by X-ray diffraction, Fourier Transform Infrared spectroscopy, and Thermogravimetric analysis. After a short period of non-stirring heat treatment, the solid-phase yield rapidly increases by 14.20 wt.%, reaching 46.70 wt.%. The softening point of the final mesophase pitch is all below 350 °C. The increase in yield and structural transformation are influenced by changes in the content of quinoline insoluble, as evidenced by the presence of C-H out-of-plane bending vibration at 670 cm−1. Based on the observed changes in composition and structure, this study proposes a hypothesis regarding the increase in mesophase pitch production during heat treatment.

Haigang Gao
Panchan Dansawad
Yi Fang
Yuming Zhang
Lixa Cao
Yanxiang Li*
Wangliang Li*
Green Chem. Technol.
2025,
2
(2), 10004; 
DOI: 10.70322/gct.2025.10004
Open Access

Article

25 April 2025

The Crystal Structure of Apatite and Copper-Doped Apatite

The recent claim of superconductivity above room temperature in Pb10−xCux(PO4)6O, where 0.9 < x < 1 (referred to as LK-99), has generated significant interest. In this study, we first investigated the detailed crystal structures of four natural apatite by single crystal X-ray diffraction (SXRD) combined with a scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDX) measurement. Secondly, pilot experiments of doping copper (Cu) atoms into the apatite lattice were carried out by high-temperature mixed pure copper and natural apatite powders. Finally, copper-doped lead apatite has been synthesized via a three-step solid-state reaction method, and its crystal structure has been determined using SXRD, SEM/EDX, and transmission electron microscopy (TEM).

Yibo Liu
Changzeng Fan*
Bing Zhang
Bin Wen
Lifeng Zhang
Green Chem. Technol.
2025,
2
(2), 10005; 
DOI: 10.70322/gct.2025.10005
Open Access

Article

13 June 2025

Development of a Tailored Culture Medium for Improved De Novo Biosynthesis of Ferulic Acid in Fed-Batch Biphasic Fermentation with Saccharomyces cerevisiae

Ferulic acid (FA) is a natural phenolic compound with diverse biological properties, widely used in the food and cosmetic industries. Its production from fermentation is a promising strategy because its extraction from biomass is costly. To enable cost-effective microbial production, medium optimization is mandatory. In this study, we focused on applying a fed-batch biphasic strategy for the production of ferulic acid (FA) from d-glucose. FA production was first assessed in a classically defined medium, 2X Yeast Nitrogen Base (YNB) without amino acids, and complex Yeast Peptone Dextrose (YEPD) medium. Finally, as FA has deleterious antimicrobial properties, continuous extraction from the broth using fed-batch biphasic fermentation was implemented. Our results showed that YEPD medium resulted in the production of 207 mg·L−1 of FA in a medium composed of 30 g·L−1 d-glucose, 10 g·L−1 yeast extract, 1 g·L−1 (NH4)2SO4, 10 g·L−1 peptone, 4 g·L−1 KH2PO4 and 2 g·L−1 K2HPO4. Fed-batch biphasic fermentation system resulted in almost a two-fold increase in FA production compared to batch one (312.6 mg·L−1 and 176.7 mg·L−1, respectively) showing the importance of fed-batch biphasic fermentation and medium detoxification.

Blandine Godon
Julien Couvreur
Fanny Brunissen
Fanny Brunois
Clémentine Fojcik
Florent Allais
Michel Lopez
Nabila Imatoukene*
Green Chem. Technol.
2025,
2
(2), 10006; 
DOI: 10.70322/gct.2025.10006
Open Access

Article

19 June 2025

Antifungal and Antibacterial Activity of Lathyrus aphaca L. Mediated Green Synthesized CdS Nanoparticles and Their Characterization

Cadmium Sulfide nanoparticles (CdS-LA hybrid nanoparticles) were synthesized here by a green approach using the precursor cadmium acetate and sodium sulphide along with the extract of a plant Lathyrus aphaca L. containing the phytochemicals which were responsible for surface modification of nanoparticles. The nanoparticle was used to evaluate their inhibition potential against species of bacteria and fungi. The nanoparticles were characterized by XRD, which demonstrates the hexagonal crystal structure. SEM confirms the homogenous surface appearance of the CdS-LA hybrid crystalline structure. EDX analysis confirms surface modification of nanoparticles by phytochemicals. FTIR confirmed the Cd-S linkage laterally with the related functional groups and the presence of metabolites on the surface of nanoparticles. The UV-visible spectroscopy confirmed the peak at the characteristic wavelength range, but a slight shift occurred in the peak of the CdS nanoparticles due to the presence of the phytochemicals. This study particularly provides an environment-friendly strategy to synthesize the CdS nanoparticles capped by Lathyrus aphaca L. extract that are biologically active due to the mediation of the plant extract. CdS-LA hybrid nanoparticles have shown inhibition potential against various species of bacteria and fungi and realize the biological importance of the green synthesis of nanoparticles especially mediated with the plant extract.

Shah Faisal
Naveed Akhtar*
Himayat Ullah
Muhammad Akif
Istikhar Khan
Fawad Ali
Numan Zada Khan Mohmand*
Green Chem. Technol.
2025,
2
(2), 10007; 
DOI: 10.70322/gct.2025.10007
Open Access

Article

25 June 2025

Fermentation of Wild Hydrolytic Bacteria Isolated from Opuntia ficus-indica, and Its Effect on Flow Behavior of Cladodes Flour Culture Media

The aim of this study was to evaluate the fermentation dynamics of two wild hydrolytic microorganisms and their effect on the flow behavior of a culture medium formulated with Opuntia ficus-indica cladode flour. Identified Acinetobacter pitti and Bacillus subtilis presented maximum values of specific hydrolytic activity (SHA) at 24 h of growth (0.21 ± 0.05 and 0.22 ± 0.01 IU, respectively). The apparent viscosity of cladode flour medium (CFM) measured by applying shear rates (66.7 s−1–0.003 s−1) in suspensions (20%) showed a significant decrease (60%) as a function of bacterial growth progressed. After fermentation, the CFM exhibited pseudoplastic (shear-thinning) behavior, which was linked to the enzymatic degradation of polysaccharides. The use of crude extracellular enzyme extracts from these wild bacteria effectively reduced medium viscosity by breaking down the plant matrix. These findings highlight the hydrolytic potential of native strains in modifying the rheological properties of cactus-based culture media, offering a low-cost alternative for biomass pretreatment and valorization in future biotechnological applications.

Manuel Octavio Ramírez-Sucre
Cindy Mariel López-Domínguez
Kevin Alejandro Avilés-Betanzos
Ingrid Mayanin Rodríguez-Buenfil*
Green Chem. Technol.
2025,
2
(2), 10008; 
DOI: 10.70322/gct.2025.10008
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