Reaction Of Formaldehyde Research Articles

Simultaneous reflectance and fluorescence measurements for portable formaldehyde determination in milk using a multi-channel spectrometer sensor

This study introduces a novel optical method for formaldehyde determination in milk, based on the hypothesis that simultaneous reflectance and fluorescence measurements can enhance detection sensitivity compared to traditional methods. We aimed to address the challenge of accurately measuring low concentrations of formaldehyde in milk, a crucial issue for food safety. By employing a multi-channel spectrometer sensor and exploiting the reaction of formaldehyde with acetylacetone to form 3,5-diacetyl-1,4-dihydrolutidine (DDL), we measured reflectance of DDL at 415 nm and fluorescence at 515 nm. The method demonstrated linearity (0.1–4 mg L−1 for reflectance, 0.1–3 mg L−1 for fluorescence) with detection limits of 0.027 mg L−1 (reflectance) and 0.030 mg L−1 (fluorescence). We successfully determined formaldehyde in milk samples (46 to 114 μg L−1) and observed a 60 % reduction in formaldehyde concentrations. This research underscores the importance of heat treatment in ensuring food safety.

Synthesis and characterization of chitosan Schiff base grafted with formaldehyde and aminoethanol: As an effective adsorbent for removal of Pb(II), Hg(II), and Cu(II) ions from aqueous media

Grafted chitosan materials show the characteristics of high stability, easy separation and recovery, and good heavy metal adsorption capacity, and have received much attention in the adsorption process. Therefore, in this work, novel grafted chitosan-based adsorbent CS-EHBSB@F-AE was prepared by a one-pot reaction of chitosan (CS), 3-ethoxy-4-hydroxybenzaldehyde (EHB), formaldehyde (F) and aminoethanol (F). The microstructure and morphology of the as-prepared composite CS-EHBSB@F-AE were characterized by FT-IR, TGA, DSC, FE-SEM, and BET analyses. The adsorption performance of the as-prepared CS-EHBSB@F-AE composite on Pb(II), Hg(II), and Cu(II) ions from aqueous was investigated using batch experiment and the effects of the initial pH of the solution, contact time, and initial metal ions concentration and temperature on the adsorption efficiency were investigated and discussed. At the best conditions, CS-EHBSB@F-AE exhibited remarkable adsorption capacity of 246.7 mg/g, 203.9 mg/g, and 234.4 mg/g in absorbing Pb(II), Hg(II), and Cu(II), respectively. The adsorption equilibrium and the kinetic studies confirmed that the ions adsorption process fits well with the Langmuir isotherm and pseudo-second-order (PSO) models. Additionally, the adsorption efficiency of Pb(II), Hg(II), and Cu(II) metal ions by the composite CS-EHBSB@F-AE was reduced by increasing the temperature from 298 K to 318 K. In addition, after the sixth ads/des cycles, the as-prepared adsorbent still exhibited high removal efficiency with a decrease in adsorption efficiency of Pb(II) (5.53 %), Hg(II) (15.43 %) and Cu(II) (8.27 %). Finally, we proposed that the ions adsorption by CS-EHBSB@F-AE has happened using the coordination of active groups containing nitrogen and oxygen atoms on the surface of the adsorbent with the Pb(II), Hg(II), and Cu(II) metal ions.

Unveiling the antibacterial efficacy of thiazolo [3,2-a] pyrimidine: Synthesis, molecular docking, and molecular dynamic simulation.

Two series of C-Mannich base derivatives were synthesized and evaluated through the reaction of formaldehyde, two thiazolo-pyrimidine compounds, and various 2°-amines. The chemical structures and inherent properties of the synthesized compounds were authenticated using a variety of spectroscopic techniques. The aseptic bactericidal potential of the compounds was assessed alongside five common bacterial microbes, with Ampicillin employed as the reference drug. Compounds 9b and 9d demonstrated comparable antibacterial activity to ampicillin against Bacillus subtilis and Bacillus megaterium, respectively, at 100 μg/mL. Furthermore, compounds 9f and 10f exhibited noteworthy action against Staphylococcus aureus (MIC: 250 μg/mL). Compounds 10b and 10f displayed excellent efficacy versus Escherichia coli, boasting (MIC: 50 μg/mL). Molecular docking studies elucidated the necessary connections and energies of molecular entities with the E. coli DNA gyrase B enzyme, a pivotal target in bacterial DNA replication. Further thermodynamic stability of the ligand-receptor complex of 10b and 10f were further validated though 200 ns molecular dynamics simulation. The findings highlight the potential of these synthesized derivatives as effective antibacterial agents and provide valuable insights into their mechanism of action.

N-Mannich Bases in the preparation of novel 4-(benzo[d]thiazol-2-yl)-5-phenylpyrrolidine-2,3-dione derivatives as potentially active antibacterial and antifungal agents

Compound 4-(benzo[d]thiazol-2-yl)-5-phenylpyrrolidine-2,3-dione (2) was taken as a precursor to synthesize some new N-Mannich bases 4, 7, and 10via the reaction of their corresponding Schiff bases 3, 6, and 9 with formaldehyde and piperidine. Similarly, N-Mannich bases 5, 8, and 11 were obtained by the reaction of their corresponding Schiff bases 3, 6, and 9 with benzaldehyde and 3-aminopyridine, or 5-aminotetrazole, or 2-aminothiazole, respectively. Moreover, N-Mannich bases 15a-l were synthesized by direct reaction of compound 2 with formaldehyde and some secondary amines. In addition, N-Mannich base 14 was obtained from its corresponding phenolic Schiff base 13 which was obtained by the reaction of benzothiazole derivative 12 with p-hydroxyaniline. Also, phenolic N-Mannich base-bearing azonine dione moiety 18 was achieved by the reaction of 15f with p-hydroxyaniline followed by the reaction of formaldehyde and piperidine to give N-Mannich base 17 which was then subjected to periodate oxidation. The targeted compounds were synthesized and characterized by spectroscopic analysis and screened for antimicrobial evaluation as antibacterial and antifungal agents. The biological evaluation showed that N-Mannich bases with tetrazole, thiazole, and phenothiazine moieties are active against B. subtilis, S. aureus (Gram-positive bacteria), E. coli, P. aeruginosa (Gram-negative bacteria), and C. albicans (Fungi strain). Meanwhile, the molecular docking study was carried out on the highest antibacterial derivatives (7, 8, 11, and 15g) with a targeted PDB: 2eg7 protein. Our docking results disclose dissimilar binding types of interactions for each derivative, suggesting varying degrees of affinity and specificity towards the target protein.

Nonenzymatic Sequestering of Formaldehyde into the Antibiotic Methylene-Bridged Dimer Phaeochromycin F by Streptomyces sp. OUCMDZ-4982 as a Possible Multipronged Chemical Defense Mechanism.

Metabolites with high chemical reactivity serve important roles in chemical defenses of organisms. Formaldehyde, as a simple and highly reactive small molecule, can be produced by microorganisms, plants, and animals. Its toxicity is well known, but information about its other biological functions remains scarce. Here, we report that the natural product SEK34b produced by Streptomyces species can react nonenzymatically with formaldehyde in water to yield the methylene-bridged dimer phaeochromycin F. This process can eliminate the toxic substance formaldehyde produced by Staphylococcus aureus. Furthermore, there is a substantial inhibitory impact of phaeochromycin F on S. aureus. We hypothesize that these constitute an integrated system of defense and attack of Streptomyces species against competitors. Our study indicates that formaldehyde can react with vancomycin and tigecycline under mild conditions to generate the derivatives bearing an imidazolidin-4-one moiety, thereby reducing the antibacterial activity of these antibiotics. These data provide a possible chemical interaction mechanism of bacteria involving the nonenzymatic reactions of formaldehyde with highly reactive natural products.

One-pot synthesis of highly substituted dihydro-2-oxopyrols using nano-SnCl4/γ-Al2O3 as a mild solid lewis acid catalyst

In this paper, highly substituted dihydro-2-oxopyrol derivatives were synthesized through a three component reaction of dialkylacetylenedicarboxylate, formaldehyde and aniline derivatives in the presence of nano-SnCl4/γ-Al2O3. The reaction was proceeded in ethanol as the solvent under reflux conditions. Nano-SnCl4/γ-Al2O3 was prepared via the reaction of SnCl4 with nano-γ-Al2O3 and characterized by FT-IR, XRD, FE-SEM, TEM, EDS,EDS-mapping, BET and TGA. Reusability of nano-SnCl4/γ-Al2O3 was examined in five runs, successfully. Short time of the reactions, good to excellent yield of products, heterogeneous conditions and reusability of the nano-catalyst are some of advantages of this green and environmental methodology.

Solvatochromism mechanism of perylene diimide radicals stabilized by low barrier hydrogen bond and detection of formaldehyde in real food samples

Formaldehyde (FA) is widely used for food preservation and whitening because of its preservative and bleaching effects. Excessive FA seriously endangers human health, so monitoring FA-treated food is of great significance for food safety. In this paper, perylene diimide radicals with the chirality (BTFPDI) and water-solubility (TFPDI-bPEI) were designed respectively based on our previous studies. Property of solvatochromism induced by these perylene diimide radicals aggregation was demonstrated by the concentration and temperature dependent absorption spectrum and the circular dichroism spectrum. Further the colorimetric monitoring of trace FA in gaseous and liquid was realized by the condensation reaction of FA with amine to induce TFPDI-bPEI aggregation. After the addition of FA, TFPDI-bPEI molecule aggregated in aqueous solution due to the specific reaction of a large number of –NH2 groups with FA, resulting in a blue-shift of the maximum absorption peak from 780 nm to 561 nm, and the detection limit as low as 0.86 μM to FA and the response time of only 20 s. This method could further detect FA in food with good recoveries and detect FA in contaminated food samples.

Exploring the essential features influencing the synthesis of methylenedianiline to support industrial processes

The most important intermediate of methylene diphenyl diisocyanate (MDI), the most widely and quantitatively produced isocyanate in the world, is methylenedianiline (MDA). MDA is industrially produced from the reaction of aniline and formaldehyde catalysed by inorganic acids, most commonly HCl. The reaction parameters used during the synthesis of MDA have a fundamental impact on the quality parameters of the resulting MDA product mixture, and thus on the properties of the final MDI product mixture as well. Although MDA is an important industrial intermediate, currently its synthesis at the industrial level is based on empirical rules, knowledge and rule of thumbs, the effects of production parameters and their magnitude on product properties are not known and not published in the literature. In this study, the correlations between the independent operating parameters and dependent product quality parameters characterizing the MDA mixture were explored by developing different regression models with the use of experimental laboratory synthesis data in order to support the industrial synthesis process with easily deployable models with satisfactorily high accuracy. After investigating the laboratory experiment data from a total of 46 individual laboratory experiments, it was found that with machine learning models almost all of the independent parameters can be described with satisfactory accuracy. The models presented in this work demonstrate that it is possible to develop models that can be used to adjust the ring distribution, isomer ratios and selectivity of the reaction with minimising by-product quantities according to market demands or to different objective functions by fine-tuning the production parameters., thus achieving an optimal product portfolio and operating cost for the industrial process as well.

Development of poly(vinyl acetate) adhesive with hot water resistance via constructing semi‐IPN/IPN structures with hydroxymethylated lignin

AbstractPoly(vinyl acetate) (PVAc) adhesive is often used in the wood industry because it can be rapidly cured at room temperature to produce a high bonding strength. However, PVAc is a linear polymer susceptible to thermal creep, so it will fail to bond in high temperature and humidity environments. In this study, the hot water resistance of PVAc adhesive is improved by introducing lignin with a complex structure to construct multiple cross‐linked networks with a high cross‐link. However, due to the large steric hindrance, the reactivity of lignin hydroxyl groups is low. In the process of preparing adhesive, alkali lignin is hydroxymethylated to improve its reactivity, and then 4,4′‐diphenylmethane diisocyanate is used as a cross‐linker to construct interpenetrating and semi‐interpenetrating polymer networks. The hydroxymethylation occurs through the reaction of formaldehyde with lignin under alkaline conditions. Optimal reaction conditions include a reaction ratio of 0.20, a reaction temperature of 80°C, and a reaction time of 3.5 h. On those conditions, the bonding strength of the lignin‐based PVAc adhesive reaches 1.8 MPa after hot‐water treatment. Therefore, the lignin‐based hot water‐resistant PVAc adhesive has shown good application potential in high temperature and humidity environments.

A robust acid-resistant chelating polymer for enhanced stabilization of lead ions in fly ash

Fly ash derived from municipal solid waste incinerators (MSWIs) harbors significant quantities of heavy metals with high leaching toxicity, resulting in detrimental environmental effects. Pb2+ in fly ash is the ion most likely to exceed permissible levels. However, chemical stabilization methods demonstrate poor efficacy in stabilizing Pb2+ under acidic conditions. Herein, we have developed a robust acid-resistant chelating polymer (25DTF) for enhanced stabilization of Pb2+ in fly ash. 25DTF was synthesized through the reaction of formaldehyde with 2,5-dithiourea. 25DTF exhibited remarkable chelation efficiency, nearing 100%, for Pb2+ in fly ash. 25DTF demonstrated exceptional chelation efficiency, surpassing 99.9%, when interacting with Pb2+ in fly ash at pH ≤ 7. Even under acidic conditions, 25DTF effectively prevented the secondary dissolution of Pb2+. Additionally, it indicated outstanding Pb2+ chelation efficiency across diverse regions of China. The 25DTF chelating agent shows considerable potential in alleviating metal ion contamination in soil, wastewater, and urban environmental management, thereby fostering advancements in environmental stewardship.

Copper-Catalyzed Multicomponent Coupling Reaction of Primary Aromatic Amines, Rongalite, and Alkynes: Access to N-Aryl Propargylamines.

In this work, a practical copper-catalyzed multicomponent coupling reaction of primary aromatic amines, rongalite, and alkynes for the direct synthesis of N-aryl propargylamines has been developed. This method could overcome the substrate limitation in A3 coupling reactions of primary aromatic amines, formaldehyde, and alkynes. Mechanistic studies revealed that rongalite acts as not only the active C1 unit but also the accelerator to activate the in situ-generated N-arylmethanimines for the coupling reaction with alkynes. This coupling reaction is highly efficient and features a broad substrate scope, as well as utility with scale-up synthesis and converting the corresponding product N-aryl propargylamines into useful heterocyclic skeletons.

Direct Observation of Gas-Phase Hydroxymethylene: Photoionization and Kinetics Resulting from Methanol Photodissociation.

Carbene species play an integral role in high-energy chemistry, transition-metal-carbene chemistry, catalysis, photolytic formation of carbohydrates, and possibly even the formation of interstellar sugars. In 1921, "reactive formaldehyde"─now known as hydroxymethylene (HCOH)─was first implicated as an intermediate in photocatalytic processes. However, due to its transient nature, direct observation of HCOH has predominantly been attained using cryogenic isolation methods. As a result, HCOH gas-phase reactivity measurements have been limited. We directly observed HCOH using photoionization spectroscopy following UV photodissociation of methanol. Our measurements show it reacts slowly with O2 at room temperature. This work provides evidence for the formation mechanism of HCOH from CH3OH and its subsequent reactivity under gas-phase reaction conditions.

Green preparation of versatile silver-based nanocomposites using whole biomass-based Tannin-Furfural as raw materials

Phenolic resin (PR) nanomaterials, which serve as excellent carriers for precious metals, are typically synthesized via the cross-linked reaction of phenol and formaldehyde, and both are toxic. Therefore, replacing them with whole biomass-based materials is an attractive alternative; however, it has proven to be a significant challenge. In this study, we successfully prepared versatile Ag-based resin nanocomposites (referred to as TFR@Ag) by utilizing whole biomass-based tannin and furfural as raw feedstock. The resulting TFR nanospheres exhibited high stability and uniformity, with tunable sizes ranging from 280 to 1430 nm by adjusting the amount of ammonia used in the synthesis process. Importantly, compared to traditional PR nanospheres, the novel and environmentally friendly TFR nanospheres possess abundant phenolic-OH groups that significantly enhance their adsorption, reduction and chelation capacity for Ag+. The highest loading amount of silver nanoparticles (Ag NPs) achieved was up to 60.3 wt% with a size of only 10.6 nm. The as-obtained TFR@Ag nanocomposites demonstrated excellent catalytic activity in treating typical hazardous dye-containing wastewater. As catalyst, the 0.4 mg TFR@Ag were capable of achieving full reduction of 2 mL 40 mg·mL−1 methylene blue (MB) and methyl orange (MO) in just one minute, exhibiting reaction rate constants of 1.71 min−1 and 2.40 min−1, respectively. Moreover, as antibacterial agents, the TFR@Ag nanocomposite effectively inhibited the growth of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) with a bacterial inhibition rate close to 100 %. This work presents a new strategy for green synthesis of multi-functional Ag-based nanocomposites that hold great potential in various fields such as catalysis, nanomaterials science and biomedicine.

Synthesis, characterization and anticancer activity of Ni(II), Cu(II), Pd(II) and Au(III) complexes derived from novel Mannich base

AbstractNew four complexes of Ni(II), Cu(II), Pd(II), and Au(III) were derived from the tridentate ligand 3‐((3‐(4‐hydroxyphenyl)‐5‐mercapto‐4H‐1,2,4‐triazol‐4‐yl)(3‐oxobutyl)amino)naphtho[2,3‐b]furan‐2(3H)‐one (L), which synthesized using condensation reaction of formaldehyde, acetone, and secondary amine (Mannich reaction). The secondary amine is a heterocyclic compound possesses two rings, naphthafuran and triazole, both rings prepared through intermolecular cyclization reactions. Considering that naphthafuran‐2‐one derived from α‐amino nitrile. The α‐amino nitrile compound contains the other triazole ring which illustrated to the structure through successive steps. The compounds were characterized using elemental analysis (C.H.N.S), FT‐IR, ultraviolet–visble spectroscopy, thermal gravimetric analysis (TGA), flame atomic absorption, molar conductivity, and magnetic susceptibility measurements. Accordingly, the probable geometries of the complexes were suggested as square planner, and they have electrolytic nature. Thus, chemical formula; [NiLCl]Cl·6H2O, [CuLCl]Cl·2H2O, [PdLCl]Cl·2H2O, and [AuLCl]Cl2·3H2O. Cytotoxic effect was studied on brain cancer cell line (AMJM cell line) at different concentrations for L and complexes. The results showed that gold(III) complex has the highest cytotoxicity among all compounds.

Synergistic photothermal catalytic oxidation of methanol and toluene mixture over Co-MOFs-derived catalyst: Interfacial and promotion effects

Herein, a series of Co/CoOx@CN nanocomposites with tunable synergistic interfacial structure were successfully obtained by a facile pyrolysis treatment. Among these nanocomposites, the nanocomposite pyrolyzed at 500 °C (denoted as Co/CoOx@CN-500) exhibited the best methanol photothermal catalytic activity (97% methanol conversion and 96% CO2 yield) under simulated solar irradiation. Compared with Co nanoparticles and Co@CN, Co/CoOx@CN-500 showed higher methanol photothermal catalytic activity. Moreover, the Co/CoOx@CN-500 also displayed a good ability to degrade methanol under outdoor natural solar. Such excellent photothermal activity mainly benefited from the strong interaction between the metals Co, CoOx and graphitic-carbon, which enhanced the photothermal effect by inducing the high work temperature, and the surface adsorb oxygen species of Co/CoOx@CN-500. Besides, the promotion effect of methanol on toluene oxidation was observed over Co/CoOx@CN-500 for the photothermal catalytic oxidation of the methanol and toluene mixture relative to their individual component. Water molecules did not affect the promotion effect of methanol on the photothermal catalytic oxidation of toluene. Reaction mechanism studies showed that 2-methylbenzaldehyde, the key intermediate formed by the reaction of formaldehyde generated by methanol oxidation and toluene, is the main reason for the improvement of the oxidation activity of toluene.

Fabrication and Characterization of an Electrochemical Platform for Formaldehyde Oxidation, Based on Glassy Carbon Modified with Multi-Walled Carbon Nanotubes and Electrochemically Generated Palladium Nanoparticles.

This study outlines the fabrication process of an electrochemical platform utilizing glassy carbon electrode (GCE) modified with multi-walled carbon nanotubes (MWCNTs) and palladium nanoparticles (PdNPs). The MWCNTs were applied on the GCE surface using the drop-casting method and PdNPs were produced electrochemically by a potentiostatic method employing various programmed charges from an ammonium tetrachloropalladate(II) solution. The resulting GCEs modified with MWCNTs and PdNPs underwent comprehensive characterization for topographical and morphological attributes, utilizing atomic force microscopy and scanning electron microscopy along with energy-dispersive X-ray spectrometry. Electrochemical assessment of the GCE/MWCNTs/PdNPs involved cyclic voltammetry (CV) and electrochemical impedance spectroscopy conducted in perchloric acid solution. The findings revealed even dispersion of PdNPs, and depending on the electrodeposition parameters, PdNPs were produced within four size ranges, i.e., 10-30 nm, 20-40 nm, 50-60 nm, and 70-90 nm. Additionally, the electrocatalytic activity toward formaldehyde oxidation was assessed through CV. It was observed that an increase in the size of the PdNPs corresponded to enhanced catalytic activity in the formaldehyde oxidation reaction on the GCE/MWCNTs/PdNPs. Furthermore, satisfactory long-term stability over a period of 42 days was noticed for the GCE/MWCNTs/PDNPs(100) material which demonstrated the best electrocatalytic properties in the electrooxidation reaction of formaldehyde.

Metal-doped M-NH4-PW catalyst with enhanced electron transfer for formaldehyde-propylene condensation to 4-methyl-1,3-dioxane

Recognizing and modifying the acid property-dependent catalytic characteristics of catalysts are of great importance for Prins condensation reaction. Herein, a series of metal-doped M-NH4-PW catalysts (M=Pt, Fe, Ir, Ru) are successfully synthesized for Prins condensation reaction of formaldehyde and propylene to produce 4-methyl-1,3-dioxane. Our findings demonstrate that the catalytic performance of M-NH4-PW catalysts is influenced by the chemical nature of metal site properties with different electron transfer abilities. Specifically, the new Lewis acid decorated by Pt metal on 4-H site is more favorable for the selective adsorption of formaldehyde and activation of its CO bond. Additionally, the synergistic effect between Pt metal sites and nearby O in [PW12O40]3− promotes the formation of CC bonds between protonated formaldehyde and propylene. Consequently, the Pt-NH4-PW catalyst exhibits high conversion (> 80 %) and simultaneous selectivity towards 4-methyl-1,3-dioxane selectivity (65 %). This strategy may provide valuable insights for developing efficient multifunctional catalysts for Prins condensation reactions.

Synthesis and Characterization of Cardanol-Based Non-Isocyanate Polyurethane.

This paper describes the synthesis of NIPU by using cardanol as starting material. A cardanol formaldehyde oligomer was first prepared through the reaction of cardanol and formaldehyde, catalyzed by citric acid. The resulting oligomer was then subjected to epoxidation with m-chloroperbenzoic acid to obtain an epoxide compound, which was subsequently used to fix carbon dioxide (CO2) and form a cyclic carbonate. Using this cyclic carbonate, along with an amine, cardanol-based isocyanate polyurethane (NIPU) was prepared. Different characterization methods, such as Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), and thermogravimetric analysis (TGA), were used to confirm the synthesis of the four intermediate products and NIPU in the reaction process. This study highlights the promise of bio-based NIPU as a sustainable alternative in a number of applications while offering insightful information on the synthesis and characterization of the material.

Synthesis of CeO2–BiVO4 nano photocatalyst material and used for the degradation of gaseous formaldehyde

Formaldehyde is one of the common volatile organic compound (VOC) found in indoor environment. Reducing indoor formaldehyde exposure levels is an important issue because toxicological studies have demonstrated its carcinogenicity. In this study, hydrothermal method was used to prepare ceria-bismuth vanadate (CeO2–BiVO4) composite photocatalyst. CeO2–BiVO4 has the advantages of high-efficiency photocatalytic activity, and high stability making it a promising photocatalytic material in the fields of energy conversion and environmental protection. As-prepared samples were characterized by X-ray diffraction (XRD), reflection ultraviolet–visible spectroscopy (UV–Vis), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and photoluminescence spectroscopy (PL). XRD, TEM, and SEM verified that the material was successfully prepared. The energy level was measured by UV–Vis, and it was verified by PL that the CeO2–BiVO4 can reduce the recombination rate of electron holes. Here, BiVO4 is added to reduce the band gap of CeO2 to produce a visible light-driven catalyst. The photodegradation reaction of formaldehyde is carried out by mixing in different proportions of BiVO4 in to CeO2. The light source used in this experiment is a green light. In the experiment of formaldehyde degradation by irradiating CeO2/BiVO4 with a green light, the concentration of product carbon dioxide (CO2) and water (H2O) increases with the irradiation time. The experimental results show that CeO2-BiVO4 (4:1) catalyst has the highest formaldehyde degradation rate of 78%, and the total reaction time is 240 min. The importance of CeO2–BiVO4 as a photocatalytic material in formaldehyde degradation is to provide an environmentally friendly and efficient method to purify indoor air. It can help reduce the potential harm of formaldehyde to human health, improve indoor air quality, and contribute to creating a healthier and more comfortable indoor environment.

Self-assembled nano-particles of chitosan amphiphilic derivative for formaldehyde fluorescent detection and its application in test strips

Excessive levels of formaldehyde (FA) represent serious health risks. Aiming at the detection of formaldehyde content, this paper proposes a self-assembly method of proportional nanoprobes. Spherical nanoparticles (NPs) were prepared by one-step condensation reaction between rhodamine B (RhB) and chitosan (CS). After CS was modified by RhB, the linear structure changed and self-assembled under the action of “hydrophilic/hydrophobic” to form a core-shell structure with a cavity structure. The hydrophobic small molecule probe N-Butyl-4-Hydrazo-1,8-Naphacticimide (NBHN) spontaneously entered into the hydrophobic cavity to form spherical particles Chitosan-Rhodamine B@N-Butyl-4-Hydrazo-1,8-Naphacticimide (CS–RhB@NBHN) with a size of about 60 nm. The hydroxyl groups on CS enrich formaldehyde through charge interaction, and promote the reaction of formaldehyde with NBHN, so that the probe can detect formaldehyde at a lower concentration (detection limit 87 nmol·L−1). The self-assembled CS-RhB@NBHN nanoparticles significantly increased the response speed of NBHN (from 30 min to 10 min). After the reaction of NBHN with formaldehyde, the PET effect is released, the fluorescence transition from red to yellow of CS-RhB@NBHN, and the visual fluorescence response effect to formaldehyde is significantly improved. With the help of smartphone color recognition software, we converted the color of the probe solution into RGB values to realize the quantitative and visual detection of formaldehyde. In addition, CS-RhB@NBHN was used for the detection of FA in leather and air.