Alicia G. Gubieda, Ana Abad-Díaz-de-Cerio, Ana García-Prieto, M. Luisa Fdez-Gubieda, Laura Cervera-Gabalda, Eduardo Ordoqui-Huesa, Alfonso Cornejo, Cristina Gómez-Polo
BACKGROUND
To address water scarcity and promote sustainable resource management, more efficient and cost-effective water treatment solutions are necessary. Particularly, pathogens in drinking water are a topic of growing concern. One promising technology is the use of photocatalytic nanoparticles activated by visible light as antibacterial agents. This study focuses on the characterization and antibacterial properties of Co–Zn ferrite nanocatalysts, tested against Escherichia coli.
RESULTS
The CoxZn1−xFe2O4 (x = 0, 0.1, 0.4 and 0.6) ferrites were synthesized by the co-precipitation method. Structural, morphological and optical analyses confirmed that these nanoparticles have a cubic spinel structure, with sizes of around 10 nm, and band gap energies suitable for visible light activation (1.4–1.7 eV). The antibacterial efficacy of the nanoparticles against E. coli was tested and compared with their photocatalytic performance employing phenol as organic pollutant model (highest phenol degradation for x = 0.6). Specifically, the antibacterial capacity of these nanoparticles was evaluated by comparing the ability of bacteria to grow after being incubated with the nanoparticles under visible light and in the dark. It was found that nanoparticles with lower cobalt content (x = 0 and 0.1) significantly reduced bacterial culturability under visible light. Transmission Electron Microscopy analysis revealed that nanoparticles with cobalt content caused bacteria to secrete biofilm, potentially offering some protection against the nanoparticles.
Safwat A. Mahmoud, Bahig M. Atia, Lamiaa Galal Amin, Mohamed Abdalla
BACKGROUND
A novel silver adsorbent, (2Z,2′ E)-2,2′-((1,10-phenanthroline-2,9-diyl)bis(methaneylylidene))bis(N-phenylhydrazine-1-carboxamide) (PHMC), was synthesized for efficient Ag+ adsorption. PHMC was prepared by refluxing 1,10-phenanthroline-2,9-dicarboxaldehyde with N-phenylhydrazinecarboxamide at 120 °C. The structural and morphological properties of PHMC were characterized using various analytical techniques including FTIR, SEM, BET surface area analysis, 13CNMR, 1HNMR, and GC–MS, to confirm the formation of PHMC adsorbent.
RESULTS
The results demonstrated that PHMC possesses an exceptional silver sorption capacity of 440.67 mg g−1 in aqueous solutions. Additionally, PHMC exhibited excellent reusability, with effective desorption of Ag(I) using a 1 M thiourea solution, enabling adsorbent regeneration. The adsorption of Ag+ onto PHMC was well described by Langmuir and D-R isotherms, as well as pseudo-second order and intraparticle diffusion (IPD) kinetic models. PHMC showed remarkable selectivity for silver, even in the presence of competing ions, and demonstrated significant stability, retaining over 95% of its initial capacity after four regeneration cycles and more than 80% after seven cycles. Thermodynamic investigations revealed that the sorption process was endothermic.
The increasing usage of tetracycline in antiviral therapy has caused severe aqueous water contamination, and advanced oxidation processes based on sulfate radicals have been recognized as an effective technique for degrading this antibiotic into harmless small molecules.
RESULTS
Herein, a strategy based on dopamine self-polymerization was utilized to synthesize the magnetite/polydopamine-ferric ion (Fe3O4/PDA-Fe3+) catalyst with excellent magnetism and abundant surface functional groups. This catalyst exhibited high performance in activation of permonosulfate for tetracycline degradation. The surface properties and chemical composition of this catalyst were characterized by scanning electron microscopy, X-ray diffraction, vibrating sample magnetometer, Fourier transform infrared and X-ray photon spectroscopy, which indicated that Fe3O4/PDA-Fe3+ could active permonosulfate to generate strong oxidizing free radicals for catalytic degradation of tetracycline. Beside its excellent catalytic activity, Fe3O4/PDA-Fe3+ also exhibited superior structural stability and reusability, and this catalyst could be simply recycled from solution using an external magnet. Additional quenching experiments and chemical environment analysis confirmed that hydroxyl, sulfate and superoxide anion radicals, singlet oxygen and surface-adsorbed oxygen contributed significantly to degradation of tetracycline.
An antifouling and acid/alkali-resistant sulfonated polyethersulfone (S-PES)/polysulfate (PSE) composite ultrafiltration (UF) membrane prepared via a nonsolvent-induced phase separation (NIPS) method was used for the purification of ulinastatin (UTI) as an examplar protein-based drug.
RESULT
The effect of the content of S-PES on the structure and UF performance of the S-PES/PSE composite UF membrane was investigated. The acid/alkaline resistance of the S-PES/PSE membranes was evaluated in the pH range 5–10 suitable for a UTI solution. UF desalination experiments were carried out on UTI elution collection solution, and the antifouling performance and long-term stability of S-PES/PSE composite UF membrane were evaluated. The results indicate that, for the optimal content of 4% S-PES, pure water flux increased from 120 to 726 L m−2 h−1, WCA decreased from 79.3° to 51.0°, and the rejection of UTI was 95.90% ± 1.1% compared to PSE. Compared with PES and PSF membranes, the flux recovery rate of the S-PES/PSE composite UF membrane was 80.63% (an increase of 32.48%), and the UTI adsorption was only 75.00 μg cm−2 (a decrease of 88.00%) after simulated antifouling experiments.
Omar Santiago Pillaca-Pullo, André Moreni Lopes, Nelson Bautista-Cruz, Waldir Estela-Escalante
BACKGROUND
Industrial effluents are continuously discharged into the environment. These wastewaters contain valuable compounds that can be reused for biotechnological applications. Coffee wastewater (CWW) is a powerful effluent that can be used for single-cell protein (SCP) production reaching important content (up to 80%). Several yeast species can be used for SCP production, but Candida species are commonly applied for this purpose (17 species reported including the novel C. sorboxylosa). In addition, SCP can be produced in bioreactors under controlled conditions under three operation modes. Thus, batch mode is frequently used but continuous mode presents interesting advantages in economic terms, although it has been poorly applied in SCP production.
RESULTS
The initial evaluation under batch operation mode showed that volumetric oxygen transfer coefficient (kLa of 101 h−1) improved biomass production (1.39 g L−1) and SCP yield (59.9%) in C. sorboxylosa. Thus, continuous mode was established at selected kLa and feeding with optimized medium composed of 87.5% (v/v) CWW, 1.38 g L−1 yeast extract, and 7.24 g L−1 (NH4)2SO4, in order to provided necessary nutrients. In this sense, the process presented higher values in dry cell weight and SCP productivity (0.57 and 0.29 g L−1·h, respectively), achieving a 3.35- and 2.90-fold increase in biomass and protein productivity, respectively, compared to batch mode. The SCP from C. sorboxylosa exhibited an interesting essential amino acid profile under continuous mode (33.704%).
Zilla Zahra, Sadia Iram, Khuram Shahzad Ahmad, Sofia Khalid, Ghulam Abbas Ashraf, Mohammad Abul Farah
<div> <section> <h3> BACKGROUND</h3> <p>Utilization of phytochemicals for the preparation of metal oxides nanocomposites has been proven to be a best alternate of chemical synthesis methods. Here, we have extracted, isolated and characterized the phytochemicals of <i>Callistemon viminalis</i> plant extract and utilized them as biofuel in the synthesis of Cu/Co and doped Cu/Co nanoparticles. <i>Callistemon viminalis</i> has been shown to have reducing and stabilizing properties. The plant extracts contain a variety of bioactive substances, including tannins, vitamins, amino acids, saponins, inositol, alkaloids, flavonoids, and terpenes. The use of plant extracts in the synthesis of NPs is a quick, dependable, nontoxic, benign, environmentally friendly, and cost-effective method. Thus, in the present work, the <i>Callistemon viminalis</i> leaves extract a synthesis of Cu/Co nanoparticles and ytterbium doped Cu/Co nanoparticles, and these nanoparticles were characterized by optical properties (UV), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-rays diffraction (XRD), and electrochemical application.</p> </section> <section> <h3> RESULTS</h3> <p>Synthesis of Cu/Co nanoparticles and ytterbium doped Cu/Co nanoparticles at room temperature have been successfully done using <i>Callistemon viminalis</i> aqueous leaf extract. Products were confirmed by conducting UV- visible spectrophotometry, FTIR, SEM, and XRD confirming the formation of cubic shaped Cu/Co nanoparticles of average diameter of 14 nm. The aqueous leaf extract acted as a capping agent and the existence of organic functional groups were confirmed by FTIR. Upon varying the Yb content in Cu/Co, the particle's size obtained from SEM showed a decrease in size. The band gap energies were also reduced with Yb doping. The stability of the produced NPs was investigated using linear sweep voltammetry LSV on this special and innovative metal oxide electrode. The LSV analysis has shown an elevation in the scan rate detection with an increase in voltage. 55.6 μA current was detected at 10 V for Cu/Co NPs. Ytterbium doped nanoparticles have shown 471.3 μ current voltage value at scan rate of 10 V. Observed value of current of synthesized Cu/Co NPs was 5.7 μA and the observed current of doped Yb(Cu/Co) was 12.5 μA. The increase in current values of dopant Cu/Co nanoparticles is due to the higher pore volume and surface area of copper, which promotes the transfer of electrons, so the current density is greater of the doped material than the composite NPs. The electrical resistivity of Cu/Co nanoparticles has shown a decline with elevation in current indicating its semiconducting nature.</p> </section> <section> <h3> CONCLUSION</h3> <p>In summa
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Virginia Montiel-Corona, Daniel Puyol, Germán Buitrón
BACKGROUND
Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is the most promising biopolymer for replacing petroleum-derived plastics from polyhydroxyalkanoates (PHA) copolymers. The mechanical properties of PHBV improve as the content of the 3-hydroxyvalerate monomer (3HV) increases. However, there is no information about the effect of light/dark cycles on PHA composition produced by phototrophic purple bacteria. This work aimed to improve the molar fraction of 3HV in the PHBV copolymer formed by a mixed phototrophic culture enriched in Rhodopseudomonas palustris, combining the effect of the illumination regime and using odd-chain fatty acids and cheese whey as carbon sources.
RESULTS
Under continuous lighting, the PHBV concentration (mg L−1) and 3HV molar fraction (%) were 508 ± 25 mg L−1 (1%), 193 ± 10 mg L−1 (22%), 252 ± 10 mg L−1 (1%), and 286 ± 10 mg L−1 (3%) for valerate, propionate, lactate, and fermented cheese whey, respectively. Interestingly, under light/dark cycles, the 3HV molar fraction increased 23-fold when using valerate (light/dark cycle of 30 min), 12-fold with lactate, and 1.5-fold with fermented cheese whey. The PHBV content (% w/w) reached was 20–25%, 14–16%, 12–15%, and 8–12% for valerate, propionate, lactate, and fermented cheese whey, respectively.
Soil in uranium mining areas is contaminated by uranium and associated heavy metals, posing a significant threat to human health and ecological security. Chelating agent assisted phytoremediation is a cost-effective and ecologically friendly remediation approach for uranium and associated heavy metals contaminated soil. In this work, a novel slow-release composite chelating agent (SRCMC-g-CMCD-EDTA/AC) was fabricated using carboxymethyl chitosan-graft-carboxymethyl-β-cyclodextrin (CMC-g-CMCD) as a slow-release carrier and EDTA/ammonium citrate (AC) as a composite chelating agent through the spray drying method, which was used for phytoremediation of soil co-contaminated with uranium and chromium.
RESULTS
CMC-g-CMCD exhibited superior slow-release performance for both EDTA and AC in comparison with CMC and CMCD. When applied to soil contaminated with uranium (U) and chromium (Cr), SRCMC-g-CMCD-EDTA/AC effectively regulated the release of U and Cr. Sunflowers (Helianthus annuus L.) grown in treated soil showed a significant increase in U and Cr uptake by 70.55% and 35.55%, respectively, and reduced leaching losses by 34.88% and 37.42%.
Eddie Lopez Honorato, Rosendo Lopez Gonzalez, Leticia Velasco, Claudia Palacio
{"title":"In Focus: Materials and the Environment Symposium (XXXI IMRC México)","authors":"Eddie Lopez Honorato, Rosendo Lopez Gonzalez, Leticia Velasco, Claudia Palacio","doi":"10.1002/jctb.7730","DOIUrl":"https://doi.org/10.1002/jctb.7730","url":null,"abstract":"","PeriodicalId":15335,"journal":{"name":"Journal of chemical technology and biotechnology","volume":"99 12","pages":"2487"},"PeriodicalIF":2.8,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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