Thermodynamics and Kinetic Modeling of the ZnSO4.H2O Thermal Decomposition in the Presence of a Pd/Al2O3 Catalyst

The sulfur–iodine thermochemical water-splitting cycle is a promising route proposed for hydrogen production. The decomposition temperature remains a challenge in the process. Catalysts, such as Pd supported on Al2O3, are being considered to decrease reaction temperatures. However, little is known regarding the kinetic behavior of such systems. In this work, zinc sulfate thermal decomposition was studied through non-isothermal thermogravimetric analysis to understand the effect of a catalyst within the sulfur–iodine reaction system context. The findings of this analysis were also related to a thermodynamic assessment. It was observed that the presence of Pd/Al2O3 modified the reaction mechanism, possibly with some intermediate reactions that were suppressed or remarkably accelerated. The proposed model suggests that zinc sulfate transformation occurred in two sequential stages without the Pd-based material. Activation energy values of 238 and 368 kJ.mol−1 were calculated. In the presence of Pd/Al2O3, an activation energy value of 204 kJ.mol−1 was calculated, which is lower than observed previously.

Physicochemical Properties of Rice Flour Suspension Treated by Ultrahigh Hydrostatic Pressure

This study investigated the physicochemical properties of rice flour suspensions under ultrahigh hydrostatic pressure (UHP) treatment. Rice flour suspensions were subjected to 200, 400, and 600 MPa of pressure for 10 min, and heat treatment was used as a control. Proximate characteristics of different rice cultivar were analyzed to amylose, damage starch content, and particle size. Changes in physicochemical properties of rice flour suspensions according to UHP treatment were analyzed to microscopic structure, iodine reaction, α-amylase hydrolysis rate, and resistant starch content. Microscopic structural analyses showed that the structures of the rice flours were altered under both heat and 600 MPa treatment conditions. Water absorption rates were highest under heat treatment (467.53–554.85%), followed by 600 MPa treatment (269.55–334.57%). Iodine reaction values increased with increasing applied pressure. α-Amylase hydrolysis rates and resistant starch contents were highest under heat treatment and increased with increasing applied pressure. Based on these results, 600 MPa treatment of rice flour suspensions was shown to be comparable to heat treatment; as a result, the development of the new rice processing method with different physicochemical properties is expected from rice cultivars treated under UHP processing methods.

Colored rice varieties of Russian breeding in terms of grain quality for development of functional rice varieties

In order to develop rice breeding material of a functional direction, technological and biochemical grain quality traits of varieties bred by the Federal Scientific Rice Centre (Rubin, Mars, Mavr, Gagat, Yuzhnaya noch) with a colored grain pericarp, high content of anthocyanins and intended for functional nutrition were studied. The varieties were grown in the valley agrolandscape zone of Krasnodar region (Russia) in 2017–2019. The studied rice varieties are included in the State Register of Protected Breeding Achievements. The grain size by weight of 1000 absolutely dry grains (weight of 1000 a.d.g.) was determined according to GOST 10842-89, fracturing on a DSZ-3 diaphanoscope, protein content was measured using an Infralum FT-10 device. The determination of amylose was carried out colorimetrically using the amylose-iodine reaction according to Juliano. The varieties have a medium-sized caryopsis (21.5-27.0 g of 1000 grains); of them, the variety Yuzhnaya noch is characterized by the smallest grain. The variety Mars belongs to the low amylose group, varieties Mavr, Rubin and Gagat to the medium amylose group, Yuzhnaya noch to the waxy group. In terms of protein content in grain, all varieties are classified as medium protein. The maximum grain fracture was in variety Mavr in the range of 19-25% and the minimum in Mars and Gagat, respectively 2-5 and 2-6%. Variations in grain size indicators, amylose and protein content of varieties are weak in all varieties of special purpose, which testified to their high stability under growing conditions.

Photometric starch-iodine determination in plant materials as influenced by ascorbic acid. Critical remarks

Following the work of Sharma et al. (1990) on the interference of ascorbic acid (AA) with starch-iodine reaction, the present authors repeated it, giving a proper explanation of the influence of AA in this reaction. AA oxidizes iodine-iodide (I-KI) reagent which makes impossible to form the blue complex with starch. Three measures are suggested to overcome the interference of AA: 1) to titrate starch solution with I-KI reagent and thus work out an I-KI amount for development of blue coloration, 2) to remove from plant material AA (and other reducing soluble substances) by washing the material with cold water or ethanol, and 3) starch solution could be treated with alkali (pH about 9), which destroys AA in 15 minutes. After acidifying the solution and adding I-KI reagent the blue complex can be determined.

Production of MgO From Residues of Saline Pools in “Las Coloradas” Yucatan, Mex. Using Thermochemical Energy Storage

This paper proposes a method of thermochemical-energy storage from magnesium sulfate recovered from salt ponds of sea water. The idea develops from a project originally thought to obtain magnesium oxide from a salt plant in the Yucatan Peninsula, Mexico. The new idea is based on the exploitation of the heat of decomposition of magnesium sulphate. In the traditional literature, closed-loop, reversible reaction is considered, whereas in this work, an open-loop is proposed; that is, sulphur dioxide is separated from the magnesium oxide before cooling down to 700°C; in this way, magnesium oxide is obtained by thermal decomposition, and at the same time, the high heat of decomposition is used to store thermal energy for electricity generation; magnesium oxide, sulfuric acid and hydrogen are co-products of the process if another iodine reaction cycle is considered. This second process is again a modification of an open-loop traditional process, to a closed-loop process where no sulphuric acid is required.