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Recycling of paper sludge waste is crucial for establishing a sustainable green industry. This waste contains valuable sugars that can be converted into important chemicals such as ethanol, poly hydroxybutyrate, and lactic acid. However, the main challenge in obtaining sugars in high yield from paper sludge is the high crystallinity of cellulose, which hinders hydrolysis. To address this, pretreatment using phosphoric acid was optimized using response surface methodology to facilitate cellulose hydrolysis with minimal energy and chemicals. The created prediction model using the response surface method considered factors such as acid concentration (ranging from 60% to 85%), consistency (ranging from 4% to 10%), temperature (ranging from 25°C to 80°C), and time (ranging from 0.5 to 4 h). The results revealed that the model's significant factors affecting the yield were acid concentration, reaction time, temperature, and the product of acid concentration and temperature, while the model's significant factors affecting the crystallinity were the consistency, the temperature, and their product. The results showed that the optimum conditions for pretreatment were using an acid concentration of 64%, temperature of 25°C, consistency of 10%, and time of 30 min. The hydrolysis of the conditionally pretreated paper sludge resulted in a weight loss of 42%, compared to only 18% weight loss in non-pretreated paper sludge. Furthermore, the optimized conditions led to low levels of furfurals and acetic acid, which are undesirable by-products that can interfere with sugar fermentation. The total sugar obtained under the optimized conditions was 0.43 g glucose/g sample (10.46 g/L), while the contents of methyl furfural, furfural, and acetic acid were 21.65, 235.7, and 4.57 mg/L, respectively. This study demonstrates the potential of phosphoric acid for pretreatment and hydrolysis of paper sludge, enabling efficient saccharification and the production of sugars with minimal undesired by-products. [ABSTRACT FROM AUTHOR]

Paper and packaging materials a lignocellulose-based natural biodegradable polymer that spontaneously releases acetic acid, aldehydes, alcohol, and ester-based volatile organic compounds (VOCs) upon ageing and these VOCs start degrading the paper products and decline their mechanical strength properties. The reactivity of the paper of unbleached wheat straw pulp towards acetic acid and hexanal, which has been proven to have more degrading effects on paper than other VOCs, was considered in this work. The papers were exposed to these volatile compounds for 90 days in an air-tight vessel under ambient environmental conditions. The results showed that hexanal was more destructive than acetic acid with regards to cellulose degradation and depletion in the mechanical strength properties. The paper properties like, tensile, tear and burst index, viscosity, pH and carbonyl group content was measured. The growth of the carbonyl group, evidence of the ageing effects in the paper, detected more in the paper exposed to acetic acid. However, the strength of paper properties declined more with hexanal. FE-SEM analysis of the sample showed the development of pores and damage of cellulose fibre upon ageing. Similarly, the damaging effects of VOCs on cellulose, hemicelluloses and lignin were confirmed by significantly reduced peak detection through FT-IR \analysis. The high crystallinity index of the paper products due to exposure to VOCs was detected by XRD analysis, which confirmed the degradation of the low molecular weight cellulose molecule. Thus, the results are strongly recommended that VOCs that generates due to natural or artificial ageing could be the leading cause of paper degradation. [ABSTRACT FROM AUTHOR]

Background: Paper mulberry is a promising alternative fodder source due to its high protein and the abundance of active components. However, paper mulberry often faces susceptibility to contamination during silage fermentation, and there is a need to improve the quality of silage fermentation of paper mulberry through exotic additives. Sea buckthorn pomace (BP) is a feed additive containing antimicrobial and antioxidant substances that help to enhance silage fermentation. Therefore, the objective of this study was to evaluate the effects of BP and Lactiplantibacillus as additives on silage fermentation and bacterial community of paper mulberry. Results: The results showed that BP and Lactiplantibacillus significantly reduced the pH and ammonium nitrogen content of paper mulberry silage (P < 0.05) and significantly increased the content of lactic acid and acetic acid (P < 0.05), resulting in more residual water-soluble carbohydrate and crude protein contents and less fiber content relative to the control. The key microorganisms in paper mulberry silage fermentation are Lactiplantibacillus pentosus and Weissella cibaria. Among these, Lactiplantibacillus favored a rapid increase in Lactiplantibacillus pentosus abundance during the pre-silage fermentation period, whereas BP favored the promotion of Lactiplantibacillus pentosus growth, resulting in higher contents of lactic and acetic acid than those of the control. Conclusions: Simultaneously adding Lactiplantibacillus and BP can effectively improve the quality of paper mulberry silage and increase the abundance of beneficial microorganisms in paper mulberry silage. [ABSTRACT FROM AUTHOR]

Based on laser inspection photography and control variable method, the development formula of indandione was systematically studied, the formulations were optimised, the influence of adding glacial acetic acid and chlorine salt to the formula on the development effect of fingermarks was further studied. The results showed that the optimal formula was formula: 0.25 g indandione, 225 mL ethyl acetate, 225 mL petroleum ether, 25 mL ice acetic acid, 25 mL storage solution (0.2 g zinc chloride, 30 mL ethanol), and suitable for domestic climate environment, which had a good effect on the porous objects of fresh and within 20 d of the aged left fingermarks; fingermark fluorescence was significantly enhanced. The ex-perimental results provide a method to follow for optimizing the formulation of indandione fingerprint de-velopment, realizing the colorimetric and fluorescence dual-mode development of sweat latent fingermarks on porous objects. But attention should be paid to the characteristics of the porous object and the control of the amount of glacial acetic acid and the type of chlorine salt. [ABSTRACT FROM AUTHOR]

Samples of papers artificially (2 to 60 days) and naturally (10, 45, and 56 years) aged were studied by the Py-GC/MS method to identify decomposition products. Possible reaction scenarios for cellulose degradation were developed. One of the degradation products is acetic acid, which can (auto)catalyze the cleavage of cellulose β(1→4)-glycosidic bonds of cellulose polymer chains. However, during 20 s of Py-GC/MS analysis, temperatures of up to 300 °C did not significantly increase or modify the formation of decomposition products of paper components. At 300 °C, the amount of several cellulose decomposition products increased regularly depending on the number of days of artificial aging and natural aging, demonstrated mainly by the generation of 2-furancarboxaldehyde, 5-hydroxymethylfurfural, and levoglucosan and its consecutive dehydration products. No correlation between the amount of lignin decomposition products and the time of aging was found when the pyrolysis was performed at 300 °C and 500 °C. Compounds present in the products of decomposition at 500 °C bear the imprint of the chemical composition of the sampled paper. Pyrograms taken at 300 °C using the Py-GC/MS method can give additional information on the changes in the chemical structure of paper during natural or artificial aging, mainly about the cleavage of β(1→4)-glycosidic bonds during aging. [ABSTRACT FROM AUTHOR]

A recent trend in the preparation of carbon dots, optically unique nanomaterials, revolves around the use of readily-available, low-cost natural resources as precursors and their multipurpose applications. In this work, a hydrothermal method for preparing biocompatible carbon dots from radish was developed. The carbon dots were then tested for sensing of Cu 2+ and acetic acid vapor. The carbon dots exhibited blue emission under UV illumination with, a quantum yield of 15%. The fluorescence emission was selectively quenched when Cu 2+ ions were added, giving a detection limit of 0.16 μM. A paper-based fluorescent sensor was fabricated and shown to sense Cu 2+ with a limit of detection of 6.8 μM. The carbon dots were able to determine the Cu 2+ concentration in real water samples, with excellent recovery and reliability. The carbon dots were also used as the sensing material in an optical electronic nose, and tested for real-time detection of acetic acid vapor. Using principal component analysis, different ratios of acetic acid to methanol in solution were successfully identified with a detection limit of 15.5%. The acetic acid concentration in a real vinegar sample was also accurately determined. Our results demonstrated that label-free carbon dots derived from readily available radish can be simply used as versatile probes, giving them potential uses in multipurpose sensing applications., (Copyright © 2018 Elsevier B.V. All rights reserved.)

In this study, paper mill wastewater and hemicellulose hydrolysate were evaluated as low-cost substrates for fungal chitosan production using Penicillium citrinum. Submerged fermentation was first studied using a bioreactor operated under batch, fed-batch and continuous modes with paper mill wastewater as the substrate. Very high removal (91%) of organics as chemical oxygen demand (COD) in the wastewater with 160 mg L-1 chitosan production by P. citrinum was obtained using the bioreactor operated under fed-batch mode for 72 h. Moreover, 86% reduction of phenolics in the wastewater with 89% decolourization efficiency was achieved in the fed-batch experiments with the bioreactor. Under the continuous mode of operation with the bioreactor, maximum chitosan production of 170 mg L-1 was observed. The effect of acetic acid addition to the wastewater for enhancing chitosan production by the fungus was further studied in a batch system. Chitosan productivity of 2.33 mg L-1 h-1 was obtained with 50 mg/L acetic acid. Various models, viz. Monod, Haldane, Andrews, Webb and Yano, were fitted to the experimental data for understanding the kinetics involved in the process. Haldane model accurately fitted the experimental data on biomass specific growth rate, acetic acid consumption rate and chitosan production rate by P. citrinum with acetic acid addition to the wastewater. Fungal fermentation of another low-cost substrate, rice straw hydrolysate, was further studied using the batch-operated bioreactor; and a maximum chitosan titre of 911 mg L−1 was achieved using the detoxified rice straw hydrolysate. Highlights Low-cost substrates for chitosan production by Penicillium citrinum are reported Acetic acid addition to paper mill wastewater enhances chitosan production Biomass growth and chitosan production follow substrate inhibition kinetics Fed-batch -operated bioreactor resulted in 91% wastewater treatment efficiency Maximum chitosan titre of 911 mg L−1 was achieved with rice straw hydrolysate [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the changes in chemical and physical properties of selected paper documents, dating from the 18th century to the present date. Paper documents from the 18th, 19th, and 21st centuries had a pH ranging from slightly acidic to alkaline values, whereas paper documents from the 20th century were more acidic. The contents of mannose, glucose, holocellulose, and lignin were significantly correlated with the pH of the paper. High contents of both carboxylic acids (acetic and formic) and the most durable monosaccharide (glucose) were found in the oldest examined paper documents originating from the 18th and 19th centuries. The lowest percentage of brightness was found in paper documents originating from 1920 and 1923. The lowest breaking length was associated with papers originating from 1920.

Highlights • Non-invasive multi-analytical approach for characterizing Japanese papers. • SPME-GC/MS provides information on the organic substances emitted by papers and fibers. • Acetic acid and 1-butanol emission are related to the papermaking process. • N-N dimethyl formammide was emitted exclusively by industrial papers. Ketones, aldehydes and heavier alcohol were preferentially emitted by fibers and homemade papers. • Higher furfural emission from fibers place further question about the use of this compound for evaluating degradation of the paper. Abstract Volatile organic compounds (VOCs) can have a strong effect on cellulose degradation, contributing in decreasing the lifetime expectancy of the paper materials, widely employed in the field of conservation. In this work, we investigated several industrial and homemade Japanese papers, as well as fibers, evaluating VOCs emission by using solid-phase micro extraction coupled with gas chromatography–mass spectrometry (SPME-GC/MS). Acetic acid and 1-butanol were highly detected in industrial and homemade papers rather than fibers, suggesting that the emission of these compounds is influenced by the production process more than by the raw material itself. Conversely, N-N dimethyl formammide was peculiar of industrial processes. Ketones, aldehydes and heavier alcohols were preferentially emitted by fibers and homemade papers. The higher emission of furfural from fibers rather than on papers place new questions about the use of this compound to evaluate the degradation state of the paper material that should be carefully evaluated. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the changes in chemical and physical properties of selected paper documents, dating from the 18th century to the present date. Paper documents from the 18th, 19th, and 21st centuries had a pH ranging from slightly acidic to alkaline values, whereas paper documents from the 20th century were more acidic. The contents of mannose, glucose, holocellulose, and lignin were significantly correlated with the pH of the paper. High contents of both carboxylic acids (acetic and formic) and the most durable monosaccharide (glucose) were found in the oldest examined paper documents originating from the 18th and 19th centuries. The lowest percentage of brightness was found in paper documents originating from 1920 and 1923. The lowest breaking length was associated with papers originating from 1920. [ABSTRACT FROM AUTHOR]

Human exposure to organophosphate esters (OPEs) can occur through contaminated food contact materials (FCMs), which may pose significant health risks. This study investigated the presence and migration characteristics of 26 OPEs in 60 plastic and paper-based food contact materials sourced from markets and online retailers. Migration experiments were conducted using three food simulants: 4% acetic acid, 10% ethanol, and 95% ethanol. Thirteen OPEs were identified in the packaging samples, with triphenyl phosphate and tris(1-chloro-2-propyl) phosphate being the most frequently detected, averaging 95.8 ng/g and 73.3 ng/g, respectively. During migration simulations, 11 OPEs were found to migrate into the food simulants, with migration concentrations ranging from 9.22 to 150 ng/cm². The health impact was assessed using hazard index and maximum cumulative ratio methods. Triphenylphosphine oxide, triisobutyl phosphate, and butylphenyl diphenyl phosphate contributed the most to the overall hazard among the 11 compounds. However, the overall risk of OPE exposure to humans was determined to be low. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biochar promoted the in-situ enrichment of Lactiplantibacillus. • Biochar elevated acetic acid yields to 37 % during early fermentation. • The sucrose-biochar combination increased lactic acid content by 15 %. • The sucrose-biochar synergy reduced CH 4 by 24.15 % in vitro rumen tests. • Biochar is a favorable strategy for anaerobic fermentation of paper mulberry. This study investigated biochar effects, either alone or combined with sucrose, on fermentation quality, microbial communities, and in vitro rumen digestion of anaerobic fermented paper mulberry. The biochar alkaline functional groups bind to lactic acid, reducing acid inhibition and promoting Lactiplantibacillus proliferation. Owing to the low sugar content of paper mulberry, lactic acid bacteria in the biochar group primarily underwent heterofermentation, resulting in the lowest lactic and highest acetic acid contents. Treated with sucrose-loaded biochar, the increased substrate supported homofermentation, leading to the highest lactic and lowest acetic acid contents, with a 15.0 % increase in lactic acid and a 22.2 % decrease in ammoniacal nitrogen compared with the control after 75 days. In vitro rumen tests showed that the biochar-sucrose group had the highest dry matter degradation rate (45.9 %) and a 24.2 % reduction in methane emissions. Concludingly, sucrose-loaded biochar is recommended as effective for lactic acid production under anaerobic conditions. [ABSTRACT FROM AUTHOR]

Aging of a power transformer’s insulation system produces carboxylic acids. These acids—acetic, formic and levulinic—are absorbed by the paper insulating material, thus accelerating the degradation of the whole insulation system. In this contribution, the effect of these acids on the aging of oil-impregnated paper insulation used in power transformer is reported. A laboratory aging experiment considering different concentrations of these three acids was performed to assess their effect on the insulation system’s degradation. Each acid was individually mixed with virgin oil, and a mixture of acids was also blended with oil. The paper’s degradation was assessed by the degree of polymerization (DPv). It was found that the DPv of paper aged with formic acid decreased much faster in comparison to the other acids.

The re-profiling from paper-grade to dissolving pulp production is a common trend for acid sulfite cooking of wood. This provides substantial changes in the composition of the spent sulfite liquor (SSL) affecting its potentialities in subsequent processing within the biorefinery concept. In this work, a comparative analysis of the chemical composition of SSL was performed from the magnesium-based acid sulfite cooking of Eucalyptus globulus wood to produce the paper-grade and dissolving pulps. More severe pulping conditions required for dissolving pulp production led to a substantial increase in volatile compounds in SSL, such as acetic acid, methanol, and furfural. At the same time, the amounts of dissolved sugars and lignosulfonates (LS) were increased to a less extent. The main changes detected in LS were related to the increase of its molecular weight, degree of condensation, and sulfonation degree. The increased concentration of the sulfuric acid in SSL was one of the reasons for these changes. [ABSTRACT FROM AUTHOR]