Physicochemistry and Utilization of Wood Vinegar from Carbonization of Tropical Biomass Waste

Pyroligneous acid also called wood vinegar is an aqueous liquid produced from pyrolysis of lignocellulose waste and biomass. In general, the pyrolysis types are classified base on heating rate mainly either fast or slow pyrolysis. The characteristic and properties of wood vinegar are primarily influenced by the type of carbonaceous feedstocks as well as the production techniques. Wood vinegar is a complex mixture of polar and non-polar chemicals with various molecular weights and compositions. Its major constituent is water (80–90%). Some physical properties; such as pH, specific gravity, dissolved tar content are, respectively, within the range of 2–4, 1.005–1.016 g/mL, 0.23–0.89% wt, and color, odor and transparency have been reported. In addition, the degree of oBrix was ranged between 1.7 and 6.6. Besides water, the chemical compositions of wood vinegars consisted of acetic acid with the largest component (30.45–70.60 mg.mL−1). A high number of phenol derivatives have been found and those in higher concentrations were 4-propyl-2-methoxyphenol (5–11 mg.mL−1) followed by 2-methylphenol (2–4 mg.mL−1). Wood vinegar has been regarded as a natural product, which claimed to be capable in several fields of application. In agriculture, wood vinegar has been used in vegetable cropping in order to combat disease, pest control, improve growth and fruit quality, seed germination accelerator as well as herbicide. In pharmaceutical and medical applications, it is used for the preparation of detoxification pad while in veterinary and animal production, incorporation of the wood vinegar in feed could promote acidity in large intestine to inhibit growth of enteropathogenic microbes. In food processing, wood vinegar has a characteristic smoke flavor, and also exhibits microbial growth inhibition. In addition, several investigators reported that bio-oil and wood vinegar obtained from fast pyrolysis and carbonization showed a high potential on organic wood preservative. In summary, the wood vinegar prepared from the tropical wood and/or biomass waste is widely beneficial. The chapter attempts to provide essential knowledge relevant to physicochemical characteristics of wood vinegar and its applications

The role of water sorption and swelling by an insoluble tablet containing cellulose, starch, or their derivative as a disintegrant during aqueous coating simulation

Surface morphology and porosity, moisture sorption, thermal property changes due to water interaction, particle swelling, and hydration capacity of excipients including four disintegrants, i.e., microcrystalline cellulose (Avicel PH102), croscarmellose sodium (Ac-di-sol), corn starch, and sodium starch glycolate (Primojel), as well as unmilled dicalcium phosphate dihydrate (Di-Tab) were studied in order to understand the roles of water sorption and swelling of the tablets made with these excipients. All sorption isotherms of the disintegrants were type II which could be treated by G.A.B. equation. The remaining sorbed moisture was found in desorption studies due to the liquid condensation and polymer structural changes during sorption. The monomolecular sorption of water was substantially higher than that of nitrogen. The fact that water molecules interact with some specific sites on the amorphous portions of a disintegrant polymer produces a high monomolecular sorption. Water eases the segmental mobility of glassy amorphous portions which, in turn, lower glass transition temperature. This could reflect the sorption capacity owing to the loss of some water sorption sites by changing from amorphous glass to rubber. Sorbed water seemed to be tightly bound on the surface of a disintegrant. This water phase was not separately seen by exothemic differential calorimetry. However, ice present in the case of Ac-di-sol and Primojel equilibrated with 95-100% relative humidity because of the water that solvated the polymer sodium salts. Ac-di-sol, corn starch, and Primojel particles significantly swelled in the medium containing water. The superdisintegrants exhibited high values of hydration capacity compared to those of conventional ones. However, the hydration capacity of Di-Tab is extremely low. The kinetics study of moisture and liquid water uptakes for Di-Tab tablets with or without a disintegrant at 15% w/w level as well as the hydration capacity study revealed that water uptake may be governed by hydrophilicity of the tablet capillary rather than the tablet porosity. The extent of swelling and water penetration of formulated tablets during simulated aqueous coating could be described by a simple linear model. It was found that Di-Tab tablets with 15% Ac-di-sol significantly swelled during aqueous coating simulation

การประยุกต์ differential scanning calorimetry เพื่อใช้วิเคราะห์ความพรุนของพอลิเมอร์ที่ใช้ในทางเภสัชกรรม

Thailand Research Fund (TRF

Comparison between the efficacy of self-prepared chlorhexidine varnishes and of EC 40®

It was reported that clinical application of chlorhexidine (CHX) varnish could reduce dental caries occurrence effectively.However, this form of CHX is not commercially available in Thailand. Our previous study showed that the released CHX from 20% and 40% self-prepared CHX varnishes were sufficient to inhibit the growth of Streptococcus mutans. This study aimed to compare the efficacy of the 20% and 40% self-prepared CHX varnishes to commercial CHX varnish EC 40®. The study included CHX release, antibacterial activity against S. mutans ATCC 25175, and the cytotoxic effect of CHX on fibroblasts. The results showed that the greatest amount of CHX was released by EC 40® followed by 40% and 20% selfpreparedCHX, which were 4,111.29 g, 2,408.7 g, and 1,136.4 g, respectively. EC 40® gave the strongest antibacterial activity; however, there was no statistical significant difference. The 20% self-prepared CHX gave the highest viability of fibroblasts. This study indicates that the self-prepared CHX should be considered to be used as antimicrobial agents for the prevention of dental caries

Behavior of Freezable Bound Water in the Bacterial Cellulose Produced by Acetobacter xylinum: An Approach Using Thermoporosimetry

The aim of the study is to examine thermal behavior of water within reticulated structure of bacterial cellulose (BC) films by sub-ambient differential scanning calorimetry (DSC). BC films with different carbon source, either manitol (BC (a)) or glycerol (BC (b)), were produced by Acetobacter xylinum using Hestrin and Shramm culture medium under static condition at 30 ± 0.2°C for 3 days. BC samples were characterized by electron scanning microscopy and X-ray diffraction spectroscopy. The pore analysis was done by B.H.J. nitrogen adsorption. The pre-treated with 100% relative humidity, at 30.0 ± 0.2°C for 7 days samples were subjected to a between 25 and −150°C-cooling–heating cycle of DSC at 5.00°C/min rate. The pre-treated samples were also hydrated by adding 1 μl of water and thermally run with identical conditions. It is observed that cellulose fibrils of BC (a) were thinner and reticulated to form slightly smaller porosity than those of BC (b). They exhibited slightly but non-significantly different crystalline features. The freezable bound water behaved as a water confinement within pores rather than a solvent of polymer which is possible to use thermoporosimetry based on Gibb–Thomson equation to approach pore structure of BC. In comparison with nitrogen adsorption, it was found that thermoporosimetry underestimated the BC porosity, i.e., the mean diameters of 23.0 nm vs. 27.8 nm and 27.9 nm vs. 33.9 nm for BC (a) and BC (b), respectively, by thermoporosimetry vs. B.H.J. nitrogen adsorption. It may be due to large non-freezable water fraction interacting with cellulose, and the validity of pore range based on thermodynamic assumptions of Gibb–Thomson theory

Thermal behavior of a pharmaceutical solid acetaminophen doped withp-aminophenol

Thermal behavior of a series of acetaminophen (APAP) doped withp-aminophenol (PANP) was studied by differential scanning calorimetry (DSC) to determine whether it exhibited a eutectic system. Within the temperature range of 120 to 200° C, accurately weighed (1–2 mg) samples sealed in hermetic pans were calorimetrically scanned with a low scanning rate of 1° C/min. The mixture formed a single eutectic with the composition ratio APAP/PANP of 0.6/0.4 at a temperature of 138° C, where it liquefied. Melting began as early as at the eutectic point, which was below the melting temperature of APAP (169° C). The melting point as well as heat of APAP fusion was depressed with the increase in doped PANP. It was postulated that there might be a deficit heat of APAP fusion in APAP doped with PANP, which was coincident with the heat consumed by early liquefaction. The deficit heat was used to correct fraction molten in the van’t Hoff law of purity determination. It was found that the purity determination of APAP doped with PANP was comparable to the UV-spectroscopic method up to the maximum doped PANP level of 8 mol percent. It was concluded that DSC was able to approach early heat of liquefaction of APAP doped with PANP. The van’t Hoff law may be applicable to the determination of APAP with the presence of PANP as a eutectic impurity