Experimental Investigation of Pyrolysis Process of Agricultural Biomass Mixture

This paper describes an experimental investigation of pyrolysis process of agricultural biomass mixture, without the addition of inert gas. The mixture consists of corn stalk, wheat straw, soy straw and oat straw with equal mass fractions. During the experiment, the mass of biomass sample inside the reactor was 10 g with a particle diameter of 5-10 mm. The sample in the reactor was heated in the temperature range of 24-650ºC at average heating rates of 21, 30 and 54ºC/min. The sample mass before, during and after pyrolysis was determined using a METTLER P1000 digital scale. Experimental results of the sample mass change indicate that the highest yield of pyrolytic gas, achieved at 650ºC, was in the range from 74 to 81%, while char yield ranged from 19 to 26%. Heating rate of biomass mixture sample has significant influence on the pyrolytic gas and char yields. It was determined that higher heating rates in the reactor induce higher yields of pyrolytic gas, while the char mass reduces. Condensation of pyrolytic gas at the end of the pyrolysis process at 650ºC produced 1.3-1.8 g of liquid phase. The results obtained represent a starting basis for determining material and heat balance of pyrolysis process as well as agricultural biomass pyrolysis equipment

Antioxidant, antimicrobial and anticancer activity of the lichens Cladonia furcata, Lecanora atra and Lecanora muralis

<p>Abstract</p> <p>Background</p> <p>The aim of this study is to investigate in vitro antioxidant, antimicrobial and anticancer activity of the acetone extracts of the lichens <it>Cladonia furcata, Lecanora atra </it>and <it>Lecanora muralis</it>.</p> <p>Methods</p> <p>Antioxidant activity was evaluated by five separate methods: free radical scavenging, superoxide anion radical scavenging, reducing power, determination of total phenolic compounds and determination of total flavonoid content. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration by the broth microdilution method against six species of bacteria and ten species of fungi. Anticancer activity was tested against FemX (human melanoma) and LS174 (human colon carcinoma) cell lines using MTT method.</p> <p>Results</p> <p>Of the lichens tested, <it>Lecanora atra </it>had largest free radical scavenging activity (94.7% inhibition), which was greater than the standard antioxidants. Moreover, the tested extracts had effective reducing power and superoxide anion radical scavenging. The strong relationships between total phenolic and flavonoid contents and the antioxidant effect of tested extracts were observed. Extract of <it>Cladonia furcata </it>was the most active antimicrobial agent with minimum inhibitory concentration values ranging from 0.78 to 25 mg/mL. All extracts were found to be strong anticancer activity toward both cell lines with IC₅₀values ranging from 8.51 to 40.22 μg/mL.</p> <p>Conclusions</p> <p>The present study shows that tested lichen extracts demonstrated a strong antioxidant, antimicrobial and anticancer effects. That suggest that lichens may be used as as possible natural antioxidant, antimicrobial and anticancer agents to control various human, animal and plant diseases.</p

Spectrophotometric determination of hesperidin by Al(III)-hesperidin complex in water-methanol solution

The composition and the stability constant of the Al(III)-hesperidin complex were determined by suitable spectrophotometric methods and pH measurements. The formation of the complex, whose concentration stability constant log K-1 ranged from 3.46 at pH=4.0 to 4.54 at pH=5.0, was established. The conditions for the spectrophotometric determination of hesperidin, by means of the complex formation, were investigated. It was found that hesperidin can be determined in the range from 2.50x10(-5)M to 1.75x10(-4)M. The application to the determination of hesperidin in orange juice is demonstrated. All investigations were carried out with 70% methanolic solutions at room temperature (20 degrees C), constant values of pH (3.7), and ionic strength (0.01)

Spectrophotometric investigation of the uranil(II)-hesperidin complex in 70% methanol

The composition and stability constant of the UO2(II)-hesperidin complex were determined by suitable spectrophotometric methods and pH-metric measurements. II was found that the uranil ion and hesperidin form a 1:2 complex in which the uranil ion is linked to the hesperidin molecule through the carbonyl and the 5-hydroxyl group. The relative stability constant, log K-2, ranged from 5.77 at pH 4.0 to 7.00 at pH 6.0. The conditions for the spectrophotometric determination of hesperidin, by means of reaction of the complex formation reaction, were investigated. Beer's law was obeyed up to 2.0x10(-5) mol dm(-3) hesperidin

Lichens as biological indicators of air quality in the urban area of Kuršumlija (Southern Serbia)

In this work, we provided a first indication of Kuršumlija (town of Southern Serbia) air quality using epiphytic lichens known as bioindicators. The investigations were carried out from April to October 2014. The analysis of thalli samples (from 15 investigated points in Kuršumlija), indicates the presence of 42 lichens taxa from 23 genera. An assessment of air quality was made by using the Index of Atmospheric Purity (IAP) and Index of Human Impact (IHI). IHI values ranged between 15 and 36. IAP values ranged between 10 and 28. According to the IAP values, it has been found that there are three different air pollution zones: “normal”, “struggle” and “lichen desert”. The latest characterize the majority of the urban area. The aim of this study is to formulate an indication of air quality using lichens as bioindicators on the basis of lichens diversity and frequency. This is of great importance because there are no continuous physical and chemical measurements of air quality in this area