Comparative studies on the effect of mineral matter on physico-chemical properties, inherent moisture and drying kinetics of Chinese lignite

2015 ◽  
Vol 93 ◽  
pp. 197-204 ◽  
Author(s):  
Pengfei Zhao ◽  
Liping Zhong ◽  
Yuemin Zhao ◽  
Zhenfu Luo
Keyword(s):  
Comparative Studies ◽  
Chemical Properties ◽  
Drying Kinetics ◽  
Mineral Matter ◽  
Physico Chemical ◽  
Kinetics Of

The effect of origin and physico-chemical properties on the kinetics of reduction of mixed NiO-Fe2O3 oxides with hydrogen

1986 ◽  
Vol 51 (10) ◽  
pp. 2098-2108 ◽  
Author(s):  
Milan Pospíšil ◽  
Jan Topinka
Keyword(s):  
Mixed Oxides ◽  
Mutual Influence ◽  
Spinel Phase ◽  
Chemical Properties ◽  
Inhibitory Effect ◽  
Chemical Parameters ◽  
Physico Chemical ◽  
Preliminary Annealing ◽  
Kinetics Of ◽  
Kinetics Of Reduction

We investigated the effect of origin and some physico-chemical parameters on the kinetics of reduction with hydrogen of two series of mixed NiO-Fe2O3 oxides differing by their composition, the character of their precursors (mixed crystalline nitrates and coprecipitated hydroxides) and their decomposition temperature.This effect manifested itself by different magnitudes of specific surfaces of the mixed oxides and coherent regions of present phases as well as by different oxidizing abilities of the surface and differences in morphology and phase composition of corresponding samples in both series investigated. Nonlinear or nonmonotonous composition dependences of physico-chemical parameters investigated point to a mutual influence of individual components, which is also a function of the system origin and which modifies its reactivity during its reduction with hydrogen. The kinetics of the reduction was studied thermogravimetrically at 320-410 °C. The reduction of oxides of the hydroxide origin is catalytically accelerated by primarily reduced nickel, whereas in corresponding samples of the nitrate series, the total NiO is bound to the spinel phase and the reduction is delayed. Experimental IR spectra, the effect of preliminary annealing and DTA of the mixed oxides point to an inhibitory effect of water, which is constitutionally bound in trace admixtures of the goethite phase, on the kinetics of reduction of samples in the hydroxide series.

scholarly journals Natural Drying of Astringent and Non-Astringent Persimmon “Rojo Brillante”. Drying Kinetics and Physico-Chemical Properties

Foods ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 647
Author(s):  
Cristina M. González ◽  
Rebeca Gil ◽  
Gemma Moraga ◽  
Alejandra Salvador
Keyword(s):  
Chemical Properties ◽  
Drying Kinetics ◽  
Added Value ◽  
Diospyros Kaki ◽  
Drying Characteristics ◽  
Water Diffusivity ◽  
Physico Chemical ◽  
Drying Treatment ◽  
Effective Water ◽  
Natural Drying

Persimmon (Diospyros kaki L.f.) crop has markedly increased in Spain, and “Rojo Brillante” persimmon is the main cultivated variety. This astringent cultivar requires de-astringency treatment before commercialization, which may involve an extra cost. Its short commercial season implies handling large volumes of fruits with consequent postharvest losses. Therefore, the development of derived added-value products is of much interest. In this study, astringent and non-astringent “Rojo Brillante” persimmons were dehydrated by following a natural drying method used in Asia. The drying kinetics and physico-chemical properties were analyzed for 81 days. The results indicated subsequent reductions in weight, water content, and water activity throughout the drying process, and the equatorial diameter decreased. All the employed thin-layer mathematical models were suitable for representing the drying characteristics of both products with similar behavior. The effective water diffusivity values were 5.07 × 10−11 m2 s−1 and 6.07 × 10−11 m2 s−1 for astringent and non-astringent persimmon samples, respectively. The drying treatment significantly decreased the soluble tannins content, and the astringent samples obtained similar values to those obtained for the non-astringent samples in 20 days. The external and internal flesh of the astringent fruit remained orange through the drying period, while brown coloration in the non-astringent fruit was observed after 57 drying days. Therefore, prior de-astringency treatment would not be necessary.

scholarly journals Characteristic Physico-chemical Properties and Potential Uses of Enset (Ensete ventricosum) Starch: Comparative Studies with Starches of Potato, Sago and Corn

2010 ◽  
Vol 57 (3) ◽  
pp. 185-192 ◽  
Author(s):  
Rieko Hirose ◽  
Yoriko Tezuka ◽  
Tomoko Kondo ◽  
Kazuko Hirao ◽  
Tamao Hatta ◽  
...  
Keyword(s):  
Comparative Studies ◽  
Chemical Properties ◽  
Ensete Ventricosum ◽  
Physico Chemical

scholarly journals Kinetics of transesterification of Madhuca Indica oil over modified zeolites: biodiesel synthesis

2015 ◽  
Vol 50 (4) ◽  
pp. 271-278 ◽  
Author(s):  
SR Pratap ◽  
SZM Shamshuddin ◽  
N Thimmaraju ◽  
M Shyamsundar ◽  
SS Reena
Keyword(s):  
Catalytic Activity ◽  
Chemical Properties ◽  
Ftir Analysis ◽  
Reaction Conditions ◽  
Physico Chemical ◽  
Biodiesel Synthesis ◽  
Basic Zeolites ◽  
Modified Zeolites ◽  
Kinetics Of ◽  
Nay Zeolites

In this article production of biodiesel from Madhuca indica oil (MI-oil) containing high % of free fatty acids (FFA) by transesterification process with methanol over basic zeolites such as NaY loaded with 5-25% KOH is presented. The zeolites were characterized by PXRD, BET and CO2-TPD methods prior to their catalytic activity studies. Optimization of reaction conditions for transesterification was conducted in order to get highest possible yield of biodiesel. 1HNMR and FTIR analysis confirms the conversion of MI-oil to biodiesel. The physico-chemical properties of MI-biodiesel were found to be comparable with that of the standard biodiesel. The NaY and KOH/NaY zeolites were found to be efficient and reusable catalysts without much loss of their catalytic activity when used for several times in biodiesel production.Bangladesh J. Sci. Ind. Res. 50(4), 271-278, 2015

Kinetics of enzymatic esterification of oleic acid and decanol for wax ester and evaluation of its physico-chemical properties

2015 ◽  
Vol 55 ◽  
pp. 12-16 ◽  
Author(s):  
K.N. Prasanna Rani ◽  
T.S.V.R. Neeharika ◽  
T. Prathap Kumar ◽  
B. Satyavathi ◽  
Ch. Sailu ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Chemical Properties ◽  
Wax Ester ◽  
Enzymatic Esterification ◽  
Physico Chemical ◽  
Kinetics Of

Assessment of various carbon-based adsorbents for separation of BTX from aqueous solution

2015 ◽  
Vol 15 (3) ◽  
pp. 649-655 ◽  
Author(s):  
Husam Faiz Haddad ◽  
Azhagapillai Prabhu ◽  
Ahmed Al Shoaibi ◽  
Chandrasekar Srinivasakannan
Keyword(s):  
Adsorption Capacity ◽  
Surface Area ◽  
Functional Groups ◽  
Activated Carbons ◽  
Chemical Properties ◽  
Bet Surface Area ◽  
Kinetics Of Adsorption ◽  
Physico Chemical ◽  
Benzene Toluene ◽  
Kinetics Of

The adsorption of benzene, toluene and xylene (BTX) was investigated covering different types of commercially available activated carbons with varied surface area and surface functional groups. The physico-chemical properties were characterized by Brunauer–Emmett–Teller (BET) surface area analysis, Fourier transform infrared (FTIR) spectroscopy and the Boehm titration method. Experiments to assess the adsorption isotherms and kinetics of adsorption were performed and the results are presented. An increase in the surface acid functional groups was found to decrease the adsorption capacity, with the highest adsorption capacity corresponding to carbon with lowest acid functionality.

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