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An incubation experiment was set up to investigate the effects of NPK fertilizers, wheat straw and food waste compost in combination with Phylazonit MC biofertilizer on the changes in 0.01 M CaCl 2 extractable nitrogen forms (NO 3 + -N, NH 4 + -N, organic-N fraction) of three types of soils. The quantities and changes in CaCl 2 -NH 4 + -N mainly depended on the adsorption capacity of soils. Higher CaCl 2 extractable NH 4 + -N values were measured in the calcareous chernozem and sandy soil with the application of NPK treatment, while in case of the chernozem soil with loamy texture no significant differences were found between the NPK and control treatments. NH 4 + immobilization appeared in pots given straw treatment. The quantity of CaCl 2 -NH 4 + -N changed within the incubation period, the direction and extent of the change were dependent of the production rates and consumption processes. In all soils the 0.01 M CaCl 2 extractable NO 3 - -N was the largest pool for plant nutrition. The highest CaCl 2 -NO 3 - -N values were found in pots given NPK and combined NPK+straw treatments, while the lowest values were measured in straw-treated pots. Wheat straw, with higher C/N ratio caused a temporary immobilization, followed by remineralization. Food waste compost, with lower C/N ratio, proved to have a good N supplying capacity. The contrasted effect of straw and compost was more conspicuous in sandy soil, in which the original NO 3 - -N content was the lowest. Higher CaCl 2 -organic N values were measured for pots treated with straw and with compost, as compared to the control. During the incubation period the amount of soluble organic-N changed, the direction and extent of the change depended on the soil type and treatments. The effect of Phylazonit MC was on the quantity of CaCl 2 extractable N fractions was not really expressed, and the significancy of the effect varied and was dependent of the soil type. Biofertilizer amendment increased the extractable NO 3 - -N in sandy soil, decreased the negative effect of wheat straw, and it also might help in decomposing wheat straw and food waste compost. The application of Phylazonit MC in the calcareous chernozem caused a significantly higher amount of organic-N, especially in straw-treated pots.

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Introduction The composites with natural lignocellulosic materials like natural fibres, shivers, straws and wood have recently been intensively investigated due to favourable mechanical properties of such materials and their

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Abstract  

Straw has the highest concentration of the natural radioisotope40K in comparison with other biofuels and as peat, wood, wood chips, and energy forest, Concentration of40K have been measured in the ash remaining after wheast straw was burnt in a water heating plant. Samples wre also taken of the wheat ears, straw, and surrounding earth. The highest concentration of40K found in the bottom ash was 6000 Bq/kg which is about twenty times higher than the activity concentration of40K in the straw and about ten times higher than the natural40K activity in the ground. Calculations of the maximum ground levels air concentration of40K using the Gaussian plume model give a value of a few hundred Bq/m3. This value is found at a distance of only 100 m from the plant because of the short stack height.

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Abstract  

The pyrolysis of wheat straw has been carried out by means of thermogravimetric analysis in inert atmosphere. The samples were heated over a range of temperatures that includes the entire range of pyrolysis with three different heating rates of 5, 10 and 20 K min−1. The activation energy values as a function of the extent of conversion for the pyrolysis process of wheat straw have been calculated by means of the Flynn–Wall–Ozawa isoconversional method, the Vyazovkin–Sbirrazzuoli isoconversional method and an iterative isoconversional method presented in this article. The results have showed that there are small differences between the activation energy values obtained from the three methods, and the pyrolysis process reveals a dependence of the activation energy on conversion and have indicated the validity of the iterative integral isoconversional method. The effective activation energy for the pyrolysis of wheat straw is 130–175 kJ mol−1 in the conversion range of 0.15–0.85. Furthermore, the prediction of the pyrolysis process under isothermal conditions from the dependence of the activation energy on the extent of conversion has been presented.

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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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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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Journal of Thermal Analysis and Calorimetry
Authors: Rosely dos Reis Orsini, Elder Moscardini Filho, Lucildes Pita Mercuri, Jivaldo do Rosário Matos, and Fátima Maria Sequeira de Carvalho

]. Several works with the coffee straw has been studied in Brazil in order to add value to this residue [ 9 – 16 ]. Studies indicate that 55% of dried fruits represent the grains, 29% the pulp, 12% the bark, and 4% the mucilage. Therefore, 45% of

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Biofuels

Part II. Thermogravimetric research of dry decomposition

Journal of Thermal Analysis and Calorimetry
Authors: Sławomir Poskrobko and Danuta Król

stalks, rice husk, rice straw, wheat straw. On the basis of TGA and DTG curves, we identified the division and the proportion of products for each kind of tested biomass, an interpretation of the process in terms of phase transformations occurring in the

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