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Abstract  

The influence of initial uranium concentration, solution pH, contact time and adsorbent mass was investigated for removal of uranium from aqueous solutions by pine wood powder and wheat straw using a batch technique. The maximum removal efficiency of uranium achieved at pH 8 and 7 for pine wood powder and wheat straw, respectively. Langmuir and Freundlich adsorption isotherms and three kinetic models of adsorption including; Elovich, Lagergren pseudo-first and Lagergren pseudo-second order were used to describe the adsorption mechanisms. The uranium sorption onto wood and wheat straw powders followed a Freundlich isotherm. The kinetic studies showed that the data fitted very well to the pseudo-second order model in the studied concentration range of uranium for both adsorbents. Uranium desorption from loaded adsorbents also studied using batch techniques as a function of desorptive reagent, desorption time and desorptive reagent concentration. The results of the experiment indicated that the optimum desorption efficiency of uranium for wood powder and wheat straw occurred in 5 min shaking time, using 1.5 M HNO3 and 2 M Na2CO3 solutions, respectively.

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Abstract  

The sustainable development of agricultural waste is nowadays a main strategy in producing neutral CO2 energy and metal removal technologies. In Egypt, large amounts of rice straw are annually burnt in the open air causing severe air pollution that could be directed to co-firing and adsorption technologies. On bench scale, rice straw was positively contributed in a clean and smokeless co-firing process with methanol due to the oxidizing effect of the alcohol. The co-firing temperature control is vital to develop the adsorptive character of the residual ash and to avoid prolonged time needed to improve the physical properties of the rice straw if applied directly as a biosorbent. The consumed methanol in the process ranges from 0.15 to 0.3 liter per each kg of straw depending on its compaction. The grossed heat value from such process may drive steam generator for electricity. The residual ash was subsequently cross-linked in uranium and heavy metals adsorption tests from solutions. The porous texture of the residual ash and the amorphous nature of the silica along with potassium content provide a suitable condition for uranium immobilization especially if phosphorus or vanadium exist. The resulted chemical precipitate is analogues in composition to meta-ankoleite (KUO2PO4·3H2O) or hydrated carnotite (K2(UO2)2V2O8)·1-3H2O respectively. The XRD data of the latter form show an enhancement in crystallinity of the amorphous precipitate with the heated samples.

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291 297 Chen, S., Ge, W., Buswell, G. A.: Molecular cloning of a new laccase from the edible straw mushroom Volvariella volvacea: possible involvement in fruit body

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Abstract  

The catalytic effects of iron, aluminum or silicon on the formation of NOX precursors (HCN, NH3 and HNCO) and HCl during wheat straw pyrolysis were studied using a thermogravimetric analyzer (TG) coupled with a Fourier transform infrared (FTIR) spectrometer in argon atmosphere. The results show that the presence of iron, aluminum or silicon decreases conversion of straw-N into NH3 with the sequence of Fe > Si > Al. The iron or silicon addition suppresses N-conversion into HCN and HNCO, and the aluminum addition has no notable influence on HCN emission during pyrolysis. The share of N-conversion to NH3 and HCN increases, but that to HNCO and NO decreases a little in the presence of added iron, aluminum or silicon. The addition of SiO2 results in the highest HCl removal efficiency.

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The present study was carried out to examine the antioxidant activity in oyster mushroom cultivated on selenium (Se) rich substrate. Pleurotus fossulatus was cultivated on Se-rich wheat straw collected from the seleniferous belt of Punjab (India) and its potential to accumulate Se from substrate was examined. Using different assay systems the modulations in the anti-oxidant profile of Se enriched mushroom was studied in comparison to the mushrooms cultivated on normal straw. The oyster mushrooms were observed to potentially mobilize Se from Se-rich substrates to fruiting bodies, resulting in significantly high uptake (37.2±0.6 μg g−1) as compared to control (3.57±0.53 mg g−1). The antioxidant activity, as determined by various assays, such as reducing power, 2,2-diphenyl-1-picrylhydrazyl free radical scavenging, and metal chelating activity, was higher in the experimental mushrooms when compared to control. The results obtained demonstrate that Se-fortified mushrooms through cultivation on straw containing organic forms of Se can be considered as natural and effective dietary supplements of organic Se for humans. The present study proposes the use of Se-rich agricultural residues as substrates for mushroom cultivation for human and livestock supplementation.

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Factors affecting the cellulase production of Aspergillus niger using sugar cane bagasse as carbon source were investigated. The highest enzyme activities were obtained, when the culture medium was supplemented with 0.133% tryptone as nitrogen source. The rate of cellulase production was considerably increased when 0.5% Tween 60 was added to the production medium. For FPA and b-glucosidase production pH 5.0, while for CMC-ase pH 5.5 was found to be optimal. The highest cellulase activities were obtained at 30 °C and 300 r.p.m. The highest saccharification degree was achieved, when alkali treated rice straw was used as substrate. The main objective of the present study was to examine the possibilities of lactic acid production from alkali treated rice straw using simultaneous saccharification and fermentation technique with T. koningii cellulases and L. delbrueckii. The highest conversion of cellulose was obtained using 6% alkaline treated rice straw supplemented with 1.2 mg enzyme/g substrate at pH 4.8 and 45 °C.

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The objective of this work was to determine the change for straw production, carbon and ash content in vegetative tissues through ten cycles of recurrent selection in bread wheat, evaluated under tilled (CT) and non-tilled (NT) soils. Twenty-four wheat genotypes, four for each one of the 0, 2, 4, 6, 8 and 10 cycles of recurrent selection (RS), were used in this study. Experiments were established during two successive seasons. Ash content was expressed on dry mass basis. To estimate the carbon content, we based our calculation on the assumption that organic matter is 50% carbon. Straw dry weight was measured. For each trait, a linear mixed model (regression) was fitted to the experimental data. In response to the number of selection cycles, the ash content percentage increased under CT and decreased under NT. Carbon content decreases under CT, but increases under NT. The sequestered straw carbon and the straw production significantly decrease under CT meanwhile there was no change under NT. The observed increase for straw ash content would be related to the highest rate of transpiration in the more advanced recurrent selection cycles. Consistent with these results, the percentage of straw carbon content decreased because of the mobilization of reserves from the stems and leaves to the grains.

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The sustainable production of wheat may be possible by integrating crop rotation with improved crop management practices. The maximum grain yield of wheat was observed when field pea was the precursor crop. The precursor crop and management levels showed a significant effect on the mean straw and grain yields of wheat. Field pea as precursor crop gave a better wheat grain yield with both improved and farmers' cultural practices. Both local and improved varieties gave a better response to management levels on the field pea precursor field. Local and improved varieties gave higher yields with intensive management and chemical fertilizer application. Field pea as precursor crop gave a combined grain yield advantage of 32% relative to barley. Management practices produced a combined grain yield advantage of 16 to 73% when field pea was the precursor crop, compared to barley. The use of field pea as precursor crop with improved management practices is essential to maximize wheat yields. Better grain yields and higher net returns were achieved with field pea as precursor crop compared to barley. Using field pea as precursor crop is the most successful management option for sustainable wheat production.

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Research on cottage industry in the Carpathian Basin has not paid very much attention to work with straw. In peasant self-sufficiency, in addition to wickerwork and rush weaving, plaits made of wheat and rye straw were among the main materials used for agricultural and household storage containers. In some areas the making of straw hats as an income-supplementing activity carried out together with agricultural work also acquired special importance. In the 19th century with the expansion of trade this cottage industry in places rose to the level of a manufacturing industry. At the turn of the century the movements promoting domestic industry and the trade exhibitions gave special impetus to this activity. It flourished right up to the Trianon decision of 1920. As a consequence of the dictated peace Hungary lost around two-thirds of its territory and economic ties were suddenly severed. In some parts of the Great Plain, e.g. in Hajdúnánás (today Hajdú-Bihar County), and especially in the villages of the Székelyföld region, traditional straw hat making has survived right up to the present as a women's activity, providing a livelihood for many women working at home. This article deals with the industrial history background, with questions affecting cottage industry in general, and with the past of once flourishing trade connections, devoting special attention to a few villages in Hungary and in the Székelyföld region in the territory of today's Romania.

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