Improving the stability of beech wood with polyester treatment based on malic acid

The improvement of durability and dimensional stability of wood properties via modification of the microstructure and wood–water interaction has been widely utilised. This study investigated polyester treatments, a possible alternative, using environmentally friendly chemicals such as malic acid to improve the beech wood (Fagus sylvatica) properties. The modified properties have been studied with four treatments using malic acid, glycerol, butanediol and succinic anhydride, mixing polycarboxylic acids and polyols. Results showed that the anti-swelling-efficiency (ASE) improved up to 70%, and the bulking coefficient improved around 23%, exhibiting an efficient penetration within the cell walls. The leaching rates (LR) of treatments and the extractables remained low, between 0.05 and 2.4%. The equilibrium moisture content (EMC) decreased by 50% for the four treatments, compared to untreated beech wood.

The Effect of Dicarboxylic Acid Catalyst Structure on Hydrolysis of Cellulose Model Compound D-Cellobiose in Water

Background: Polycarboxylic acids are of interest as simple mimics for cellulase enzyme catalyzed depolymerization of cellulose. In this study, DFT calculations were used to investigate the effect of structure on dicarboxylic acid organo-catalyzed hydrolysis of cellulose model compound D-cellobiose to D-glucose. Methods: Binding energy of the complex formed between D-cellobiose and acid (Ebind), as well as glycosidic oxygen to dicarboxylic acid closest acidic H distance were studied as key parameters affecting the turn over frequency of hydrolysis in water. Result: α-D-cellobiose - dicarboxylic acid catalyst down face approach showed high Ebind values for five of the six acids studied; indicating the favorability of down face approach. Maleic, cis-1,2-cyclohexane dicarboxylic, and phthalic acids with the highest catalytic activities showed glycosidic oxygen to dicarboxylic acid acidic H distances 3.5-3.6 Å in the preferred configuration. Conclusion: The high catalytic activities of these acids may be due to the rigid structure, where acid groups are held in a fixed geometry.

Protein Binding of a Novel Platinum-Based Anticancer Agent BP-C1 Containing a Lignin-Derived Polymeric Ligand

Platinum (Pt) antineoplastic agents remain indispensable for the treatment of oncological disease. Pt-based drugs are mainly used in the therapy of ovarian cancer and non-small-cell lung carcinoma. A novel platinum-containing antineoplastic agent BP-C1 is a complex of diamminoplatinum with an oxygen-donor polymeric ligand of benzene-polycarboxylic acids, isolated from natural lignin. The aim of the study was to investigate ex vivo protein binding of BP-C1. Protein binding of BP-C1 was tested using equilibrium dialysis. Pooled blood plasma was used in the study. Control solutions contained the same dosages of BP-C1 in PBS (pH 7.2). Plasma and control solutions were submitted to equilibrium dialysis across a vertical 8 kDa cut-off membrane for 4 h at 37 °C under gentle shaking. Platinum was quantified in dialysis and retained fractions using inductively coupled plasma mass spectrometry after microwave digestion. The dialysis system was tested and validated; this showed no protein saturation with platinum. A medium degree of binding of platinum to macromolecular species of ca. 60% was observed. The study showed the maintenance of a high fraction of free BP-C1 in the bloodstream, facilitating its pharmacological activity.

Biodegradation of cellulose fibers functionalized with CuO/Cu2O nanoparticles in combination with polycarboxylic acids

Sustainable biodegradation of cellulose fibers is critical for composting after the end of a product’s life. In this study, we aimed at investigating the effect of in situ synthesized CuO/Cu2O nanoparticles (NPs) with biocidal concentration on the biodegradation behavior of cotton fibers pretreated with 1,2,3,4-butanetetracarboxylic acid (BTCA) and succinic acid (SUC). Biodegradation of the fibers was evaluated by soil burial tests in garden soil and in model compost after different soil burial times. The results showed that the application of BTCA, SUC, and CuO/Cu2O NPs did not affect the hydrophilicity of the samples and allowed a smooth biodegradation process. The morphological and chemical changes during biodegradation, evaluated by FESEM and FTIR analyses, showed that the presence of CuO/Cu2O NPs slightly hindered biodegradation of the fibers after 18 days in soil. However, biodegradation was much faster in the model compost, where all samples, regardless of their chemical modification, almost completely degraded after only 11 days. Intense microbial growth on the surface of all samples after nine days of burial in garden soil and model compost was confirmed by the presence of proteins produced by the microorganisms. The total number of microorganisms in the garden soil remained almost unchanged and increased in the model compost after the burial test. The only exception was the sample with the highest concentration of CuO/Cu2O NPs, which caused a reduction in microbial growth but not complete growth inhibition. These results clearly showed that during material degradation, the cellulosic material supporting microbial growth prevailed over the suppression of microbial growth by CuO/Cu2O NPs.

Comparison of the Methods for Determining Pyrogenically Modified Carbon Compounds

The soil organic matter (SOM) is searched for the biomarkers and specific features associated with the effect of wildfires by the case study of peat soil, Rheic Hemic Histosol (Lignic), in the south of the middle taiga of the Komi Republic. It is shown that fires considerably influence the peat organic matter. Pyrogenic activity is assessed according to the content of charcoal particles. SOM is examined using solid-state 13C-NMR spectroscopy to determine the concentrations of polycyclic aromatic hydrocarbons (PAHs) and benzene polycarboxylic acids (BPCAs). The used methods allow for diagnosing the effects of wildfires on the SOM composition. In the horizons with the signs of pyrogenesis, the share of carbon represented by aromatic fragments increases as well as the PAH concentration, mainly at the expense of naphthalene, phenanthrene, and chrysene. The carbon stock of pyrogenically modified compounds, amounting to 4.4 kg/m2, is for the first time assessed in the European north based on the BPCA content. The characteristics of pyrogenically changed organic compounds and their fragments obtained by different methods correlate well: the Pearson coefficient for the correlation of the carbon content in aromatic compounds (Caryl) with total BPCA content is R = 0.84 (p < 0.05) and with individual BPCAs, R = 0.81–0.90 (p < 0.05).

Microwave-assisted combustion to produce benzene polycarboxylic acids as molecular markers for biochar identification and quantification

Biochar is a promising carbon dioxide removal (CDR) technology for climate change mitigation. Current procedures for its determination are lengthy, labor-intensive, and difficult to conduct. Benzene polycarboxylic acids (BPCA) are the most promising molecular markers for identification and quantification of biochar and its quality as they specifically represent the stable polyaromatic backbone of biochar. Therefore, using the BPCA method, its stability and, thus, its C sequestration potential could be used for CDR accounting. The current BPCA method relies on a specific high-pressure digestion apparatus, which is not available around the world. Therefore, the aims of the present work were (i) to compare the conventional high-pressure nitric acid oxidation with a microwave-assisted digestion technique and optimize the oxidation conditions in such a way that previous results are comparable with future ones, and (ii) to significantly reduce the digestion time of soil samples of 8 h and to develop a suitable routine method that produces comparable and reproducible results. For this purpose, soil and control sample series were prepared for different temperature–time-program. Obtained results were compared with the values of the conventional method both for individual samples and for the whole dataset separately. To ensure the representativeness of the results, in addition to various soil samples with different properties, we included two reference materials into our data set, one without biochar (wheat flour) and a biochar sample. Our results showed that conventional nitric acid oxidation in the BPCA determination at 170 °C and 8 h can be substituted by digestion in a microwave reaction system (CEM Mars6) at 190 °C and 1 h. Our results further showed that this condition needs to be strictly matched, because, otherwise, over- or underestimation of biochar quantity and/or quality will be the consequence. The goal of a less time-consuming BPCA extraction from soil samples was achieved by reducing the extraction time from 8 to 1 h using the microwave-assisted method. However, one disadvantage of the new method is that five times more sample material and chemicals are needed for further BPCA analysis, compared to the original method.

Analysis of Additives in Gypsum Coatings Based on Melamine, Polycarbonate Salts, Polycarboxylate, and Polycarboxylic Acids

In this paper, we evaluate different gypsum coating additives that are available on the market, which are categorized by their chemical bases. The results will serve as a reference for future investigations of new additive bases in order to improve the properties of gypsum. As such, the objective of the this study is to assess the workability, mechanical behavior, and crystalline structure of calcium sulfate combined with different retarding and fluidifying bases, including melamine bases, which have a compressive strength of 19.32 N/mm2 and handling times with polycarbonate salts of up to 117.58 min. The following study presents the results of standard mechanical tests, analyzing semi-hydrated calcium sulfate (without additives) as a reference, along with the addition of melamines, synthetic melanin polymers, polycarbonate salts, polycarboxylates, and a polycarboxylic acid (citric acid). We already know that the addition of these additives will modify the mechanical properties of calcium sulfate, such as the Shore C surface hardness, flexural strength, modulus of elasticity, and compression resistance, which is the object of this study.

Dyeing Property Improvement of Madder with Polycarboxylic Acid for Cotton

Cotton fabrics were dyed with the madder and compounds of citric acid (CA) and dicarboxylic acids [tartaric acid (TTA), malic acid (MLA), succinic acid (SUA)] as cross-linking agents and sodium hypophosphite (SHP) as the catalyst. The molecular structures and crystal structures of the dyed cotton fabrics were analyzed using Fourier-transform infrared spectroscopy (FTIR) and X-ray diffractometry (XRD), respectively. The results showed that the polycarboxylic acids esterified with the hydroxyl groups in the dye and cellulose, respectively, and the reaction mainly occurred in the amorphous region of the cotton fabric. Compared with the direct dyed cotton fabric, the surface color depth (K/S) values of the CA, CA+TTA, CA+MLA, CA+SUA cross-linked dyed cotton fabrics increased by approximately 160%, 190%, 240%, 270%, respectively. The CA+SUA cross-linked dyed cotton fabric achieved the biggest K/S value due to the elimination of the negative effect by α-hydroxyl in TTA and MLA on esterification reaction, and the cross-linked dyed cotton fabrics had great levelness property. The washing and rubbing fastness of the cross-linked cotton fabrics were above four levels. The light resistance stability and the antibacterial property of the cross-linked dyed cotton fabrics was obviously improved. The sum of warp and weft wrinkle recovery angle (WRA) of the CA+SUA cross-linked dyed cotton fabric was 55° higher than that of raw cotton fabric, and its average UV transmittance for UVA was less than 5% and its UPF value was 50+, showing a great anti-wrinkle and anti-ultraviolet properties.

Single Step Mercerization and Formaldehyde-Free Polyfunctional Finishing on Cotton Fabrics

Mercerization, the treatment of cotton with concentrated sodium hydroxide under tension, is performed to enhance absorption, luster, strength and dimensional stability. After mercerization, the unreacted sodium hydroxide is neutralized with acids. Neutralization with polycarboxylic acids (PCAs) is likely not only to crosslink the cellulose molecules, but to also enhance other functional attributes like crease recovery behavior, flame retardancy, and soil release properties. In this research, four PCAs with different functional groups were used for fabric neutralization to merge mercerization and poly- functional finishing into one continuous process. The PCA treated fabrics were then assessed for their performance. All four PCAs were effective in improving crease recovery and soil release properties, and reducing the flammability, of the treated cotton fabric.

Terra Preta Properties in Northwestern Amazonia (Colombia)

Whereas many researchers still approach Terra Preta (TP) as a soil category, new evidence suggests that TP refers to a directional grading of soil property changes (i.e., color, pH, nutrients, etc.) within human-made soils, originating from human activities in pre-Columbian times. Currently, most TP research focuses on the Brazilian part of the Amazon basin, but only little information is available on TP soils in the Colombian Amazon. Here, we sampled four TP and surrounding soils in the Colombian Amazon region at different soil depths and analyzed them for (i) general soil properties such as color, pH and texture, (ii) soil organic carbon and black carbon (BC) contents, the latter using benzene polycarboxylic acids as molecular marker, (iii) phosphorus availability based on sequential fractionation, and (iv) microbial residue contents using amino sugars. Our data from Colombia’s middle Caquetá River and Leticia confirmed that SOC, BC, and total P were present in significantly higher concentrations in the TP areas than the surrounding soils, while pH values and microbial residue contents were unchanged. The enrichment of P forms comprised both easily extractable and stable P pools, which both dominated to a different degree, both in TP and adjacent soils. The different degree of SOC, BC and P enrichment suggests different amounts of waste disposal by the ancient populations at different TP sites, now warranting further research for reconstructing ancient population sizes from TP chemical analyses.