Addition Of Formaldehyde Research Articles

Lignin utilization from black liquor as raw material lignin resorsinol formaldehyde adhesives (LRF)

Black liquor is the result of pulp processing which contains several chemical compounds such as lignin, carbohydrate degradation products, resins and fatty acids. The main objective of the study was to determine the amount of lignin content contained in black liquor from the kraft process and its potential as a raw material for adhesives. Several research results state that the lignin contained in black liquor can be used as an adhesive. Lignin was isolated from black liquor by means of repeated deposition (reprepitation). The lignin obtained was then tested by FTIR, then the lignin was used as an adhesive with the addition of resorcinol and formaldehyde with an applicative composition of lignin resorcinol formaldehyde adhesive on a resin with a mole ratio of lignin (L) : resorcinol (R) : formaldehyde (F) = 1: 0.5 : 2; 1 : 0.3 : 2; with an additive content of 1.5% of the solid resin. Then tested for specific gravity, pH, content of non-volatile solids, viscosity, and gelatination. The results of the study were in the form of black liquor, dark brown to blackish in color with the form of a slightly viscous concentrated liquid. In testing with a pH meter, it showed that the initial pH of the black liquor was 12, this indicates that the waste pulp in the form of leachate is alkaline. Indicators on pH and specific gravity alone do not meet PF adhesive standards. The shape, appearance, viscosity (thickness), residual evaporation and gelatinization period are in accordance with PF adhesive standards. The results obtained from the ratio of different moles of resorcinol do not differ much from the test results, but it can be seen from the data that the specific gravity of the LRF adhesive (1:0,5:2) is closer to the standard for PF adhesive, although the distance between the two values is not much different. Overall this adhesive has the potential and needs further research for its application.

Silver-modified nitrogen-doped graphene quantum dots as a sensor for formaldehyde in milk using headspace micro-extraction on a single-drop of aqueous nanoparticles dispersion

BackgroundFraudulent practices used to distort the quality of milk and derivatives include the addition of formaldehyde. ResultsA formaldehyde sensor was developed based on the luminescence of newly proposed N-doped graphene quantum dots modified with silver (N-GQDs-Ag) that were prepared using a simple method. A microdroplet of the nanoparticle dispersion was used to collect formaldehyde vapor by headspace single-drop micro-extraction (HS-SDME). After, the microdroplet was diluted in water, the nanoparticle photoluminescence quenching, caused by the analyte, was measured. The strong luminescent quenching allowed a detection limit at 1.7 × 10−4% w/v. Response was selective towards formaldehyde. SignificanceThe method was effective and a cost-effective method for screening analysis of milk samples with matrix interferences minimized due to the nature of nanoparticle (prepared using Tollen's reagent) and due to the probing at the headspace of the sample cell. Results were statistically similar to those obtained using liquid chromatography.

Three-Dimensional Dosimetry by Optical-CT and Radiochromic Gel Dosimeter of a Multiple Isocenter Craniospinal Radiation Therapy Procedure.

Craniospinal irradiation (CSI) is a complex radiation technique employed to treat patients with primitive neuroectodermal tumors such as medulloblastoma or germinative brain tumors with the risk of leptomeningeal spread. In adults, this technique poses a technically challenging planning process because of the complex shape and length of the target volume. Thus, it requires multiple fields and different isocenters to guarantee the primary-tumor dose delivery. Recently, some authors have proposed the use IMRT technique for this planning with the possibility of overlapping adjacent fields. The high-dose delivery complexity demands three-dimensional dosimetry (3DD) to verify this irradiation procedure and motivated this study. We used an optical CT and a radiochromic Fricke-xylenol-orange gel with the addition of formaldehyde (FXO-f) to evaluate the doses delivered at the field junction region of this treatment. We found 96.91% as the mean passing rate using the gamma analysis with 3%/2 mm criteria at the junction region. However, the concentration of fail points in a determined region called attention to this evaluation, indicating the advantages of employing a 3DD technique in complex dose-distribution verifications.

Effects of formaldehyde ( Parasite‐S ®) on biofilter nitrification from a cold and a warm freshwater RAS

The effect of Parasite-S® (an aqueous formaldehyde solution) on the nitrification processes of biofilters was evaluated in two recirculating aquaculture systems (RASs). Rearing tanks in the warmwater RAS contained yellow perch (Perca flavescens) and grass carp (Ctenopharyngodon idella) with an initial weight of 166.8 kg and a mean density of 39.5 kg/m3. Rearing tanks in the coldwater RAS contained rainbow trout (Oncorhynchus mykiss) and lake trout (Salvelinus namaycush) with an initial weight of 1377.8 kg at a system density of 41.9 kg/m3. Parasite-S® was administered to the entire system on four consecutive days in both trials to achieve a nominal concentration of 14.8 mg/L formaldehyde (40 mg/L formalin) at the biofilter. Removal efficiencies for total ammonia nitrogen (TAN) and nitrite nitrogen were measured as indicators of biofilter nitrification processes. The active ingredient in Parasite-S®, formaldehyde, was measured until it was below the method detection limit of 0.8 mg/L. TAN volumetric removal rate was significantly decreased in both systems after formaldehyde addition and remained below pre-exposure efficiency in the coldwater RAS. Nitrite nitrogen volumetric removal rate was not significantly different, but the slope and intercepts were less after formaldehyde addition indicating an effect on the nitrifying bacteria. Although removal rates were decreased, no mortality occurred after four consecutive formaldehyde indefinite bath exposures in either system.

A review of the presence of formaldehyde in fish and seafood

Fish is an excellent source for high-quality protein, good fat (omega 3 and 6), vitamins (B, D), and minerals (Ca, P, Zn, I, Mg, K, etc.) and can lower blood pressure and help reduce the risk of a heart attack or stroke. The illegal addition of formaldehyde (FA) to extend the shelf life is a common problem reported in many countries and the FA is classified as a group 1 human carcinogen by the International Agency for Research on Cancer (IARC). There is also the natural formation pathway of FA in fish and seafood. This article summarises the FA levels in fish and seafood (from 2000), formation pathways, health risk assessment, regulations, and analytical techniques to measure FA. It is shown that the reported FA levels are frequently higher than the recognised safety level of 5 mg/kg. This review highlights the requirement of a broad scale effort to measure the indigenous FA levels in fish and ensure that this can be differentiated by the illegal addition of FA. This will allow the strengthening of regulations and allow monitoring to detect and deter the practice of illegal addition of FA to fish and seafood.

Whey Protein Isolate Film and Laser-Ablated Textured PDMS-Based Single-Electrode Triboelectric Nanogenerator for Pressure-Sensor Application.

The use of biopolymers for realizing economical and eco-friendly triboelectric nanogenerators (TENGs) widens the application prospects of TENGs. Herein, an animal-sourced whey protein isolate (WPI) film, processed and prepared by a simple aqueous solution preparation and drop-casting technique, is applied to demonstrate its potential use in bio-TENGs. With the addition of formaldehyde in WPI, the films result in a free-standing and flexible film, whereas the pure WPI films are difficult to handle and lack flexibility. A TENG device based on the WPI and the laser-ablated textured polydimethylsiloxane (PDMS) for pressure-sensor application were developed. The output voltage of the TENG comprising WPI increased nearly two-fold compared to the TENG without WPI. A simple single-electrode TENG device configuration was adopted so that it could be easily integrated into a wearable electronic device. Moreover, WPI film exhibited tribo-negative-like material characteristics. This study provides new insights into the development of biocompatible and eco-friendly biopolymers for various electronic devices and sensors.

A camphor-based fluorescent probe with high selectivity and sensitivity for formaldehyde detection in real food samples and living zebrafish

A novel and simple camphor-based fluorescent probe (CH) was synthesized for detecting formaldehyde (FA) with high specificity and efficiency. A significantly enhanced green fluorescence was clearly observed only with the addition of FA because of specific recognition site homoallylamino group of FA. After treating with FA, the homoallylamino group on probe CH was converted to aldehyde group via the 2-aza-Cope rearrangement mechanism, which was demonstrated with high-resolution mass spectrometer (HRMS) analysis and density functional theory (DFT). Moreover, the experiment results manifested that the detection of FA with probe CH can be performed in a nearly perfect aqueous solution with low detection limit, large Stokes shift and wide pH adaptation range. Meanwhile, a simple filter paper, loaded with probe CH, was available to detect gaseous FA. The probe CH was also successfully applied to the detection of FA in real food and water samples. Furthermore, the fluorescence imaging experiment verified that the probe CH can effectively monitor FA in living zebrafish.

Development of a High-Strength and Adhesive Polyacrylamide Gel for Well Plugging.

Addition of melamine formaldehyde (MF) as a crosslinker containing hydroxymethyl to partially hydrolyzed poly(acrylamide) (HPAM) generated covalently crosslinked in situ gels through chemically nucleophilic attack by hydroxymethyl groups to amide in an HPAM backbone, which was demonstrated by FTIR spectrum analysis and rheological studies. NH4Cl could act as a catalyst to reduce the gelation time from 7 days in dilute water to 8 h in the presence of 0.8 wt % NH4Cl. Compared to high-temperature HPAM/phenol/formaldehyde and HPAM/Cr3+ gel systems, this gel has better adhesion and higher strength over a broad range of temperature from 60 to 100 °C under reservoir conditions with a denser and hook-like three-dimensional microstructure. Pressure-bearing capacity experiments demonstrated that the gel could efficiently plug high pressure from underneath to seal the wellbore, attributing to its high strength and good adhesion. This study could aid petroleum engineers in applying soft materials on controlling the pressure via polymer gels.

Formaldehyde degradation in denitrifying woodchip bioreactors: Effects of temperature, concentration and hydraulic retention time

Formalin is applied in certain aquaculture systems to control parasites infestations as well as bacterial and fungal diseases. This study investigated the capacity of end-of-pipe denitrifying woodchip bioreactors to remove potentially harmful amounts of residual formaldehyde (FA) from aquaculture effluents. Formaldehyde was readily removed by experimental- and field-scale denitrifying woodchip bioreactors and the removal of FA was found to be a combination of an initial adsorption of FA to woodchip surfaces (52 ± 2.8 g FA/m3 woodchips) and microbial degradation. Volumetric FA removal rates reaching 261 ± 27 g FA/m3/d were found at FA inlet concentrations of 90 mg FA/L and hydraulic retention times (HRT) of 5 h. High FA removal efficiencies ranged from 88.3 ± 4.6–99.8 ± 0.2% found for FA inlet concentrations –up to 105 mg FA/L and HRTs between 3.4 and 15 h. Microbial FA degradation rates in woodchip bioreactors were positively correlated to temperature with a Q10 value of 2.27 and a corresponding Arrhenius temperature coefficient of 1.086 for the investigated temperature range of 7–23 °C. At a commercial, outdoor recirculating aquaculture system (RAS) three full-scale woodchip compartments, achieved an average volumetric FA removal rate of 29.4 ± 0.2 g FA/m3/d and a removal efficiency of 82.5 ± 0.8% during the first 24 h following addition of FA. The results demonstrated that woodchip bioreactors are efficient in removing residual FA from RAS effluents and that nitrate removal was transiently enhanced during FA removal.

A Golgi Apparatus-Targeting, Naphthalimide-Based Fluorescent Molecular Probe for the Selective Sensing of Formaldehyde.

Formaldehyde (FA) is a colorless, flammable, foul-smelling chemical used in building materials and in the production of numerous household chemical goods. Herein, a fluorescent chemosensor for FA is designed and prepared using a selective organ-targeting probe containing naphthalimide as a fluorophore and hydrazine as a FA-binding site. The amine group of the hydrazine reacts with FA to form a double bond and this condensation reaction is accompanied by a shift in the absorption band of the probe from 438 nm to 443 nm upon the addition of FA. Further, the addition of FA is shown to enhance the emission band at 532 nm relative to the very weak fluorescent emission of the probe itself. Moreover, a high specificity is demonstrated towards FA over other competing analytes such as the calcium ion (Ca2+), magnesium ion (Mg2+), acetaldehyde, benzaldehyde, salicylaldehyde, glucose, glutathione, sodium sulfide (Na2S), sodium hydrosulfide (NaHS), hydrogen peroxide (H2O2), and the tert-butylhydroperoxide radical. A typical two-photon dye incorporated into the probe provides intense fluorescence upon excitation at 800 nm, thus demonstrating potential application as a two-photon fluorescent probe for FA sensing. Furthermore, the probe is shown to exhibit a fast response time for the sensing of FA at room temperature and to facilitate intense fluorescence imaging of breast cancer cells upon exposure to FA, thus demonstrating its potential application for the monitoring of FA in living cells. Moreover, the presence of the phenylsulfonamide group allows the probe to visualize dynamic changes in the targeted Golgi apparatus. Hence, the as-designed probe is expected to open up new possibilities for unique interactions with organ-specific biological molecules with potential application in early cancer cell diagnosis.

Boosting Efficient Ammonia Synthesis over Atomically Dispersed Co-Based Catalyst via the Modulation of Geometric and Electronic Structures

Boosting Efficient Ammonia Synthesis over Atomically Dispersed Co-Based Catalyst via the Modulation of Geometric and Electronic Structures

Tannin-furanic foams modified by soybean protein isolate (SPI) and industrial lignin substituting formaldehyde addition

Soybean protein isolate (SPI) was tested in this study as a crosslinker and formaldehyde substitute for preparing high biomass content sustainable rigid tannin-furanic-SPI (TFS) and lignin-tannin-furanic-SPI (LTFS) versatile foams. Additionally, flame retardancy was improved by lignin used as a natural fire-retardant. Fourier-transform infrared spectroscopy (FT-IR), coupled with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF-MS), revealed a covalent cross-linking reaction between tannin and SPI. TFS and LTFS foams showed by scanning electron microscopy (SEM) a closed cell structure without any pores. The incorporation of SPI resulted in enhanced mechanical properties and reduced pulverization ratios, improved thermal stability and increased thermal conductivity (approximately 0.042–0.044 W/m K compared with control foam. Furthermore, the TFS foams exhibited outstanding flame retardancy and suppressed smoke generation while undergoing combustion. These results were supported by a higher limiting oxygen index (LOI) value, a lower heat-release rate, and a higher char residue, obtained by LOI and cone calorimetry. The addition of lignin further enhanced the thermal properties and flame retardancy of TFS foams although it decreased their mechanical performance. The TFS and LTFS foams were environmentally friendly, as shown by the low formaldehyde emission measurements. This novel sustainable TFS foam appears to have a good potential for industrial application.

The Study of Formaldehyde and Borax Content on Salted Fish from Several Markets in Tembilahan Indragiri Hilir, Riau

Fisheries and marine sector is one of the potential sectors in Indragiri Hilir district, Riau. Local fishermen make efforts to preserve the catch by salting it. Although salt can extend product shelf life, there are still many salted fish producers that add formaldehyde and borax to reduce production costs. The addition of formaldehyde and borax is carried out with the aim of extending product shelf life so that producers do not lose. The aim of this study was to determine the presence of formalin and borax content in salted fish products in several markets in Tembilahan. The sampling method in this study was simple random sampling by taking three different samples of salted fish, namely salted belukang, salted kembung, and salted gulama in three different markets in Tembilahan. Samples were tested for formalin and borax using test kit. The results of the qualitative formalin content test showed that from 9 samples of salted fish from several Tembilahan markets, there were 5 positives samples containing formaldehyde. The five samples were salted salted fish belukang, salted fish kembung, salted fish gulama from central market, and salted fish gulama and salted fish kembung from Parit 11 market. In the other hand, the salted fish samples were also tested qualitatively for borax content test. The qualitative test results of borax on 9 samples from several markets in Tembilahan showed no color change on the turmeric paper after immersion in the sample solution. This indicates that all salted fish samples is negative for borax content.

Characterization of lignin streams during ionic liquid/hydrochloric acid/formaldehyde pretreatment of corn stalk

This work investigated the role of formaldehyde (FA) in lignin anti-condensation during corn stalk pretreatment based on 1-butyl-3-methylimidazolium chloride ([C4C1im]Cl)/hydrochloric acid (HCl). As a result of the aldolization reactions between FA and lignin, the condensation of lignin fragments was inhibited, and lignin remained in soluble fragmental molecules. Characterizations on the compositional and structural changes of lignin and its degraded products during pretreatment (80 °C–100 °C, 2–5 h) with FA addition in comparison with those in DO/HCl/FA or [C4C1im]Cl/HCl were conducted. Results revealed that the structural features of lignin were affected by FA addition and solvent type. In the [C4C1im]Cl/HCl/FA system, FA stabilization was unfavorable for the cleavage of β-O-4′ bonds and lignin with low S/G ratio (3.4) and high molecular weight (Mw = 9920 g·mol−1) was extracted. The compositions of degraded products were considerably affected by FA addition.

Properties of the western juniper (Juniperus occidentalis) strandboard

This work investigated the feasibility of using western juniper (Juniperus occidentalis) as a material to manufacture oriented strandboard (OSB) panels. Four different material combinations of juniper sapwood, heartwood, and fibrous bark were compared with regular southern yellow pine (Pinus sp.) strands. The OSB panels were made at an oven-dry density of 560 kg/m3. One pine control panel was also made at a higher density of 650 kg/m3 with a 5% addition of phenol formaldehyde (PF) resin and a 0.5% addition of wax. The single-layer panels were formed with a hot press, and the physical and mechanical properties were tested according to the ASTM standard D1037 (2020). The testing indicated that western juniper is a potential material for manufacturing of OSB panels. The properties of the juniper panels were equivalent or slightly better than those of the southern yellow pine panels at the same density level, except for the modulus of elasticity (MOE). The lower density of the juniper OSB panels may have benefits in construction applications and can decrease transportation costs.

NMR Metabolomics of Saurida tumbil Fish Treated with Formaldehyde Solution as Misconduct Food Preservation Method

ABSTRACT The use of formaldehyde for fish preservation is common in developing countries like Indonesia, even though there are rules for food safety practices. Law enforcement has not been successfully implemented, as officials are unable to distinguish between external formaldehyde that has been added to fish as a preservative and internal formaldehyde that is naturally produced during the fish deterioration process. This study presents nuclear magnetic resonance (NMR) metabolomics of Saurida tumbil fish, a common fish that produces a relatively high amount of formaldehyde during the deterioration process, which was preserved at chilled temperature after treatment with 0% (control), 3%, and 5% formaldehyde. Results of the study showed that the average of formaldehyde residue in 0% (control), 3%, and 5% was 12, 28, and 26 mg/kg, respectively. Meanwhile, metabolomics analyses showed that trimethylamine oxide (TMAO) and trimethylamine (TMA) are the major factors (97.44%) that discriminate between the treated and untreated fish. A high amount of TMAO and low TMA indicates the addition of external formaldehyde and conversely. These results may serve as a baseline for a specific marker to develop a high throughput screening method for the detection of formaldehyde preservation in post-harvest fisheries products.

Smartphone-based digital images as a novel approach to determine formaldehyde as a milk adulterant

Milk is an important source of protein and its consumption has gained relevance because of new evidence for its nutritional and functional role for humans. On the other hand, milk quality has been hindered by tampering, including the addition of formaldehyde to mask product deterioration and increase its shelf life, although this substance may cause harm to consumers. Taking these aspects into account, a novel, fast, greener, portable, and cost-effective method is proposed for the determination of formaldehyde in milk. This method relies on smartphone-based digital image colorimetry of the product formed upon reaction with the Schiff reagent, followed by conversion of the images into RGB values using free application software. Sample preparation only involved protein precipitation in an acidic medium and analyte determination required only a few micrograms of the reagents. The proposed method achieved a limit of detection as low as 120 μg L−1 formaldehyde with a linear response up to 1250 μg L−1 and good precision (CV = 2%, n = 20). Matrix effects were negligible after protein precipitation with recoveries of formaldehyde spiked milk samples within 92–106%. The accuracy was assessed using a reference procedure (HPLC with UV detection after analyte derivatization and liquid–liquid extraction) and the results agreed at the 95% confidence level. The procedure is applicable to whole, semi-skim, and skim milk processed using pasteurization or ultra-heat treatment (UHT).

Effects of formaldehyde on fermentable sugars production in the low-cost pretreatment of corn stalk based on ionic liquids

Low cost processing of lignocellulosic biomass is of great importance for sustainable chemistry and engineering. Herein, a low cost system composed of 1-butyl-3-methylimidazolium chloride ([C 4 C 1 im]Cl), HCl and formaldehyde (FA) was developed for the pretreatment of corn stalk at 80 °C. The efficiency of this technology was compared with that in dioxane system or without FA addition. Due to FA stabilization, the extent of acid-hydrolysis of carbohydrate fraction can be significantly decreased while 70% above of lignin was removed with the pretreatment of [C 4 C 1 im]Cl/HCl/FA system at 80 °C for 2 h. A maximum reducing sugar yield of 93.7% and glucose concentration of 7.0 mg⋅ml −1 were subsequently obtained from enzymatic hydrolysis of the slurry. There were great differences in compositions of small molecule degraded products obtained with FA addition or not. The present [C 4 C 1 im]Cl based system exhibits great potential of substituting volatile organic solvents ( i . e . dioxane) in developing low cost lignocellulosic biomass pretreatment at low temperature. Also, this work would gain insight into understanding on the roles of stabilization methods on the economic improvement of IL based biomass processing.

Napthalimide-based fluorescent probe for selective and sensitive sensing of formaldehyde and biological applications

Formaldehyde (FA) is a colorless, flammable, foul-smelling chemical used in building materials and in the production of numerous household chemical products. To develop a fluorescent chemosensor for FA, a newly prepared probe 1 containing napthalimide as a fluorophore and hydrazine as a binding site of FA was designed and prepared. The amine group of the hydrazine reacts with FA to form an imide bond. Indeed, the absorption band of probe 1 at 438 nm shifted to 443 nm upon the addition of FA, indicating that the condensation reaction occurred. Also, the addition of FA to probe 1 induced a large enhancement of the emission band at 532 nm compared with the relatively very weak fluorescent emission of probe 1 alone. This high specificity toward FA was observed over other competing analytes such as Ca2+, Mg2+, acetaldehyde, benzaldehyde, salicylaldehyde, glucose, glutathione, Na2S, NaHS, H2O2, and tert-butylhydroperoxy radical. The typical two-photon dye present in probe 1 also afforded intense fluorescence upon excitation, even at 800 nm, demonstrating that probe 1 could be used for a two-photon fluorescent probe for FA sensing. Probe 1 had a quick response time in the sensing of FA at room temperature. In addition, breast cancer cells treated with probe 1 exhibited intense fluorescence imaging upon exposure to FA, indicating that probe 1 could be used for monitoring FA in living cells. This probe can lead to new possibilities for unique interactions with biological molecules for applications.

Efficacy of physical and chemical treatments on the inactivation of bovine leukosis virus present in milk.

PurposeThe objective of the present study was to evaluate the efficacy of pasteurization, freezing, the addition of formaldehyde and peroxymonosulfate on the inactivation of the bovine leukemia virus (BLV) present in milk.Materials and MethodsA sheep bioassay was carried out in 40 sheep, which were intraperitoneally inoculated with leukocytes from milk infected by the BLV previously treated with one of the virus inactivation methods. Five study groups were evaluated: (1) control group: milk without previous treatment, (2) pasteurization group: milk treated by pasteurization, (3) freezing group: milk treated by freezing for 36 hours, (4) formaldehyde group: 0.1% formaldehyde, and (5) peroxymonosulfate group: 0.05% peroxymonosulfate. The inoculated animals were followed for 10 weeks.ResultsAt week 10 post-inoculation, all the animals (8/8) of the control group and the peroxymonosulfate group were seropositive to BLV, while no animals were seropositive (0/8) to BLV in the remaining three groups. Statistically significant differences were found between the pasteurization, freezing and formaldehyde groups with respect to the control (p<0.001) and peroxymonosulfate groups (p<0.001).ConclusionThe results indicate that pasteurization, freezing and formaldehyde processes are efficient in inactivating the BLV and can be used in milk to prevent the transmission of the virus.