Synthesis and characterization of a bio-aldehyde-based lignin adhesive with desirable water resistance

Wood-based panels find widespread application in the furniture and construction industries. However, over 90 % of adhesives used are synthesized with formaldehyde, leading to formaldehyde emission and associated health risks. In this study, an entirely bio-based adhesive (OSL) was innovatively proposed through the condensation of multi-aldehyde derived from the oxidization of sucrose (OS) with sodium lignosulfonate (L). This approach positioned oxidized sucrose (OS) as a viable substitute for formaldehyde, ensuring safety, simplicity, and enhance water resistance upon reaction with L. The optimization of the OSL adhesive preparation process involved determining the oxidant level for high sucrose conversion to aldehyde (13 % based on sucrose), the mass ratio of OS to L (0.8), and hot-pressing temperature (200 °C). Notably, the shear strength of 3-plywood bonded with the developed adhesive (1.04 MPa) increased to 1.42 MPa after being immersed in hot water at 63 ± 3 °C for 3 h. Additionally, the plywood specimens exhibited excellent performance after soaking in boiling water for 3 h, resulting in a shear strength of 1.03 MPa. Chemical analysis using Fourier-transform infrared spectroscopy (FTIR), 1H nuclear magnetic resonance (NMR), and X-ray photoelectron spectroscopy (XPS) confirmed an addition reaction between L and OS, forming a dense network structure, effectively enhanceing the water resistance of OSL adhesives. Furthermore, compared with lignin-formaldehyde resin adhesive (LF), the OSL adhesive exhibited superior wet shear strength. This study offered an innovative approach for developing lignin-based adhesives utilizing a biomass aldehyde (OS), as a promising substitute for formaldehyde in the wood industry. The findings indicated that this approach may advance lignin-based adhesives, ensuring resistance to strength deterioration under highly humid environmental conditions.

Extraction of the cellulose nanocrystals via ammonium persulfate oxidation of beaten cellulose fibers

The effect of beating starting pulp was investigated on the oxidation efficiency of ammonium persulfate (APS), the yield, and the properties of the CNCs. The beaten pulp and the subsequent CNCs were characterized, respectively, by different techniques. The CNCs were classified as CNC1 and CNC2, dependent on ultrasonication. It showed that the beating exposed more free OH groups in the pulp and enhanced the yield and surface charges of CNCs. Compared to the CNC2, the CNC1 had a higher surface charge, higher crystallinity, higher thermal stability, shorter length, smaller length distribution, and slightly larger width. The CNC1 and CNC2 had similar rheological properties. For the beaten pulp with a beating degree of 25°SR, the yields of the CNC1 and the total CNCs reached the maximum, 42.65 and 34.11 %, respectively. The surface charges of the CNC1 and the CNC2 also reached the maximum, -44.5 and - 33.6 mV, respectively. Their crystallinity indexes were 80.07 and 75.42 %, respectively. The lengths of the CNC1 and the CNC2 were 157.31 ± 30.61 and 214.92 ± 65.52 nm, and their widths were 10.13 ± 2.74 and 9.43 ± 2.99 nm, respectively. Therefore, proper beating enhanced the APS oxidation efficiency and influenced the CNCs properties.

Respiratory afflictions during hairdressing jobs: case history and clinical evaluation of a large symptomatic case series

OBJECTIVES

Respiratory symptoms at work are common among hairdressers. Various working materials, most notably bleaching ingredients such as ammonium persulfate, have been made responsible. The objective of this study is to achieve a better understanding of work-related respiratory symptoms of hairdressers by describing common features in a large affected collective.

METHODS

One hundred forty-eight hairdressers with respiratory symptoms at work presenting between 2012 and 2019 were consecutively included in a case series. Anamnestic and diagnostic data including pulmonary function and allergy testing were retrospectively compiled from records and analysed. Additionally, cases were categorised in five groups with respect to occupational causation certainty.

RESULTS

30% of the predominantly female collective had changed jobs or were on longer sick-leave. Besides respiratory symptoms, 10% also reported contact urticaria to blonde dyes. In 60% an obstructive airway disease was confirmed. A specific hypersensitivity reaction to ammonium persulfate was found in 15%. Group 1 with a proven immunological occupational causation showed significantly lower age (p < 0.001) and tenure time (p = 0.001), higher sensitization rates against environmental allergens as well as a higher total IgE (p = 0.015), compared to group 4 (obstructive airway disease, specific occupational causation unlikely).

CONCLUSIONS

This case series contributes to a better characterization of work-related respiratory symptoms in hairdressing as one of the largest examined collectives of symptomatic hairdressers. Ammonium persulfate as the most common specific cause showed signs of a type-I-like hypersensitivity reaction with typical risk factors for atopy. Prick testing is recommended in all symptomatic cases. However, a specific occupational causation often cannot be proved.

Ammonium persulfate treatment on carbohydrate polymers and lignin of wood improved sound absorption capacity

The rational design of sound absorption boards made of wood materials is an exciting area of research. This article describes a simple and inexpensive method to increase the sound absorptions capacity of Malas hardwood (Homalium foetidum Roxb.) using ammonium persulfate treatment. The reaction parameters such as the concentration of ammonium persulfate and reaction time were optimized. The results of X-ray photoelectron spectroscopy, X-ray diffraction, attenuated total reflectance-Fourier transforms infrared spectroscopy, and scanning electron microscopy demonstrated that ammonium persulfate could significantly affect carbohydrate polymers and lignin of wood by improving oxygen functionalities. The quantitative analysis of carbohydrate polymers (hemicellulose and cellulose) and lignin were evaluated. These changes in carbohydrate polymers and lignin enhanced the air permeability (83.6%) and average sound absorption coefficient at each frequency range 500-1000 Hz (2.6%), 1000-2000 Hz (4.9%), 2000-4000 Hz (17.4%), and overall 500-6400 Hz (20.8%) compared to the control samples. These results could be beneficial for new research and wood-based sound absorption materials to regulate the acoustic environment in houses.

Oxidation treatment on wood cell walls affects gas permeability and sound absorption capacity

This research aimed to study the efficacy of oxidation in wood cell walls by ammonium persulfate solution and the performances in sound absorption coefficients and gas permeability for cross sectional Oak wood (Quercus mongolica) species. Reaction parameters were optimized and extensive instrumental characterization techniques were used to study cell wall modifications, such as X-ray photoelectron spectroscopy, X-ray diffraction, attenuated total reflectance Fourier transforms infrared spectroscopy, and scanning electron microscope. The oxidation treatment changed the chemical compositions of wood (hemicellulose, cellulose, and lignin), boosting wood porosity (12%) and gas permeability (39%). The effectiveness accelerates improvement of average sound absorption coefficient at each frequency range: 250-500 Hz (4.6%), 500-1000 Hz (26.8%), 1000-2000 Hz (31.8%), 2000-6400 Hz (57.8%) and overall 250-6400 Hz (47.1%) compared to the control samples. Simple wood oxidation treatment could be helpful for novel research and wood based sound absorption materials to manage the acoustic housing environment.

Separation of hazardous polyvinyl chloride from waste plastics by flotation assisted with surface modification of ammonium persulfate: Process and mechanism

Plastic separation becomes an effective method to improve the plastic recycling by concentrating a single component from complex plastic mixtures. Based on advanced oxidation process, surface modification assisted by ammonium persulfate ((NH₄)₂S₂O₈) was applied to selectively wet plastic surface, achieving the separation of hazardous polyvinyl chloride (PVC) from acrylonitrile butadiene styrene (ABS), polystyrene (PS), and polycarbonate (PC) in forth flotation. The mechanisms were investigated through contact angle, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), as well as scanning electron microscope (SEM). The floatability of PS, PC, and ABS reduces owing to the introduction of carbonyl (O = CO), hydroxyl (-OH), and amide (O = C-NH₂) on plastic surfaces, which is the result of the oxidation by sulfate radical (SO₄^∙-) and the hydrolysis of nitrile group (CN) and butadiene (CC). Then, available reaction equations of ABS, PS, and PC were established to supplement the mechanisms of surface modification. The optimal conditions for flotation separation of PVC are (NH₄)₂S₂O₈ concentration 0.2 M, temperature 70 °C, pretreatment time 30 min, pH 10, flotation time 4 min, terpineol dosage 20 mg/L, and particle size 3-4 mm. The recovery and purity of PVC reach 100 % and 99.7 ± 0.2 % respectively, favoring the reuse of separated waste plastic.

Removal of multi-pollutant from flue gas utilizing ammonium persulfate solution catalyzed by Fe/ZSM-5

A nano-sized iron loaded ZSM-5 zeolite (Fe/ZSM-5) catalyst was firstly used to activate (NH₄)₂S₂O₈ solution for the simultaneous removal of multi-pollutant from flue gas. The simultaneous removal efficiencies 100% of SO₂, 72.6% of NO and 93.4% of Hg° were achieved under the condition that the catalyst dose was 0.8 g/L, concentration, pH and temperature of (NH₄)₂S₂O₈ solution were 0.03 mol/L, 5 and 65 °C, respectively. The stability of catalyst was checked by a continuous test, proving that the catalytic activity was maintained for 4 h and the leached iron reached low levels. Based on the catalyst characterizations, product analysis and literatures, the removal mechanism was speculated preliminarily, during which, OH and SO₄^- played key roles for oxidizing NO and Hg° into NO₃^- and Hg²⁺.

Degradation of sulfolane using activated persulfate with UV and UV-Ozone

This study investigates the degradation of sulfolane in aqueous system by (NH₄)₂S₂O₈/UVC and (NH₄)₂S₂O₈/O₃/UVC. While bubbling O₃ significantly decreased the reaction time, the experimental results in both cases were consistent: firstly, the degradation of sulfolane followed pseudo-first order kinetic models, secondly, the reaction rates were affected by persulfate dosages, UV light intensity, initial pH and concentration of carbonate/bicarbonate present. Low concentration of chloride (less then 100 ppm) had no effect on the reaction rate. Application of (NH₄)₂S₂O₈/O₃/UVA for degradation of sulfolane was also investigated. It was found that for higher sulfolane degradation kinetics, higher concentrations of persulfate was required under UVA irradiation. Finally, (NH₄)₂S₂O₈/UVC was evaluated for its applicability for degradation of sulfolane in groundwater samples.

Highly efficient and selective leaching of silver from electronic scrap in the base-activated persulfate - ammonia system

A system composed of persulfate salt and ammonia in highly alkaline aqueous solution is developed and examined for leaching metallic silver from elements of the electronic waste materials (e-scrap). Strong base activates persulfate ions providing in situ generation of highly reactive oxygen molecules. The oxidized metal forms then well soluble complex ions with ammonia ligands. The kinetic studies of the leaching process were performed for pure metallic silver. They revealed that the efficiency of the process is affected by the type of the persulfate salt. By employing potassium persulfate one obtains significantly (more than 50% for silver plates and more than 100% for silver powder) increased efficiency of silver dissolution compared to the solution composed of either sodium or ammonium persulfates. In the range of persulfate concentrations between 0.02 and 0.23mol/L the apparent reaction order with respect to the persulfate concentration was similar for all persulfate salts and was estimated to be around 0.5. The room temperature (22±2°C) seems to be an optimal temperature for the leaching process. An increase in the temperature resulted in the significant drop in the silver dissolution rate due to the decreased solubility of oxygen. Based on these results a possible mechanism of dissolving silver is discussed and the optimal composition of the leaching solution is formulated. The obtained formulation of the leaching solution was applied for the extraction of silver coatings of Cu-based e-waste scrap and the obtained results revealed an important effect of copper in the mechanism of the leaching process. The regression analysis of the leaching curve indicated that each gram of base-activated potassium persulfate under the specified conditions may leach almost 100mg of silver coatings in a form of well soluble diamminesilver (I) complex. The silver complex can be relatively easy reduced to metallic silver. The method developed is relatively cheap, low toxic and does not produce harmful by-products.

Determination of the Relative Effectiveness of Four Food Additives in Degrading Aflatoxin in Distillers Wet Grains and Condensed Distillers Solubles

The food additives sodium bisulfite, sodium hypochlorite, citric acid, and ammonium persulfate were evaluated for their effectiveness in degrading aflatoxin in samples of distillers wet grains (DWG) and condensed distillers solubles (CDS) obtained from an industrial ethanol plant. Aqueous food additive solutions, 0.5% by weight, were added to DWG or CDS at the level of 0.5 ml/g of sample, and the materials were heated at 90°C for 1 h. Sodium bisulfite was not effective in degrading aflatoxin in either DWG or CDS. Among the four food additives tested, sodium hypochlorite was the most effective. However, it bleached the substrate and left an off-odor. Citric acid and ammonium persulfate reduced aflatoxin levels by 31 to 51%. Citric acid is the most promising additive for degrading aflatoxin because it has been classified as generally recognized as safe by the U.S. Food and Drug Administration. Aflatoxin reduction was enhanced by increasing the citric acid addition level and prolonging the heating time. Reductions of 65 and 80% in DWG and CDS, respectively, were obtained by the addition of 2.5% (by weight) citric acid and heating at 90°C for 1 h. Aflatoxin levels in DWG and CDS were gradually reduced with prolonged heating at 90°C, even without the addition of food additives. Aflatoxin reductions of 53 and 73% were achieved in DWG and CDS as a result of heating at 90°C for 5 h.

Recovery of gold from waste electrical and electronic equipment (WEEE) using ammonium persulfate

This paper presents a novel methodology to recover gold from waste electrical and electronic equipment (WEEE) using ammonium persulfate ((NH₄)₂S₂O₈). Gold was recovered as a fine coating using substrate oxidation without shredding or grinding process. The WEEE sample was characterized giving values of Au: 1.05g/kg, Fe: 86.00g/kg, Ni: 73.64g/kg, Cu: 26.65g/kg. The effect of (NH₄)₂S₂O₈ concentration (0.22-1.10M), oxygen (0.0-1.4L/min) and L/S ratio (10-30mL/g) on the main responses (substrate oxidation and Au recovery) was investigated implementing response surface methodology with numerical optimization. A quadratic model was developed and quantities greater than 98% of Au were recovered. The findings presented suggest that, optimized quantities of ammonium persulfate in aqueous highly oxygenated media could be used to extract superficial gold from WEEE.

Persistence of respiratory and inflammatory responses after dermal sensitization to persulfate salts in a mouse model of non-atopic asthma

Background

Exposure to ammonium persulfate (AP) has been reported to be the main cause of occupational asthma in hairdressers. The aim of this study is to assess how long the asthmatic response to AP can be induced after dermal sensitization in a mouse model.

Methods

BALB/c mice received dermal applications of AP or dimethylsulfoxide (DMSO) (control) on days 1 and 8. They then received a single nasal instillation (challenge) of AP or saline on days 15, 22, 29, 36, 45, 60 and 90. Respiratory responsiveness to methacholine was measured 24 h after the challenge using a non-specific methacholine provocation test. Pulmonary inflammation was analysed in bronchoalveolar lavage (BAL), and total serum immunoglobulin (Ig) E, IgG1 and IgG2a were measured in serum samples. Histological analysis of lung slides was performed.

Results

Mice dermally sensitized and intranasally challenged with AP showed respiratory responsiveness to methacholine as long as 45 days after initial sensitization, as well as increased percentage of neutrophils in BAL compared with the control group. At day 60, dermally sensitized mice still presented bronchial hyperresponsiveness, while the percentage of neutrophils returned to baseline levels similar to those of controls. Total serum IgE increased significantly on day 22 after dermal sensitization. Total serum IgG1 and IgG2a increased from 45 days after dermal sensitization and remained high at 90 days.

Conclusions

Both respiratory responsiveness to methacholine and airway inflammation responses decrease with increasing time between sensitization and challenge. Respiratory responsiveness to methacholine tends to persist longer than inflammation.

Assessment of iodine status among pregnant women in a rural community in ghana - a cross sectional study

BACKGROUND

Pregnancy is associated with parallel increase in both iodine, and thyroid hormone requirements suggesting that, there may be the need for additional iodine intake during this period to prevent potential iodine insufficiency. Medically, an excess or reduced intake of this micronutrient has negative effects on the individual's health. This study aimed at identifying the pattern of iodine levels among pregnant women at Kissi, Ghana.

METHOD

A cross-sectional study was carried out among pregnant women on antenatal care at Kissi Health Centre (KHC) which serves the rural town with a population of about 4,500, located in the Komenda/Edina/Eguafo/Abirem (KEEA) municipality in the Central Region of Ghana. Demographic information, iodated salt usage and other pertinent information such as tobacco use were captured using a questionnaire. In addition, urine iodine concentration was estimated through the Ammonium per sulfate method after collecting on-the-spot urine samples.

RESULTS

Prevalence of iodine deficiency in pregnant women was 42.5 %. Of the 80 participants who were on iodized salt, only 16.25 % had mild iodine deficiency with none suffering from moderate or severe iodine deficiency. Of the 40 participants who did not use iodized salt, 35 %, 30 %, and 30 % suffered from severe, moderate and mild iodine deficiency respectively.

CONCLUSION

The high prevalence of iodine deficiency reported in this study suggests that urgent national measures are required to correct iodine insufficiency in pregnant women in these communities.