Clay Minerals Affect the Solubility of Zn and Other Bivalent Cations in the Digestive Tract of Ruminants In Vitro

Ruminants ingest large quantities of clay minerals along with inorganic soil constituents in roughages. The layered structure of clay minerals, however, may adsorb cations and may, thus, interfere with the ruminants’ supply of essential trace metals, such as Zn, Mn, Cu, and Fe. As quantitative knowledge about interactions between clay ingestion and essential trace metal metabolism are largely lacking, this in vitro study focussed on the effect of clay on the solubility of dietary Zn and other bivalent trace metals in the digestive tract of ruminants. Therefore, buffered rumen fluid was used for the simulation of ruminal conditions (RC), acidified rumen fluid (pH 2) was used for abomasal conditions (AC), and duodenal chyme was used for duodenal conditions (DC). These media were added with gradient levels of zinc and incubated at 39 °C for 24 h in the absence or presence of clay minerals. Soluble Zn, Cu, Mn, and Fe were derived by centrifugation (10,000× g) of incubated media, and the supernatants were analysed. Clay depressed the solubility of added Zn in ruminal (65.3% vs. 16.5%), abomasal (97.7% vs. 33.7%), and duodenal conditions (41.3% vs. 21.1%), the results of which were statistically significant (p < 0.001). Moreover, clay reduced dissolved Cu (µg/mL) (RC: 0.13 vs. 0.10; AC: 0.16 vs. 0.13; DC: 0.10 vs. 0.08) and Mn (µg/mL) (RC: 3.00 vs. 1.80; AC: 5.53 vs. 4.80; DC: 3.18 vs. 1.77) (p < 0.05 in all cases). The presence of clay minerals increased the concentrations of solubilised Fe (µg/mL) in abomasal (1.80 vs. 2.86, p < 0.05) and duodenal conditions (1.76 vs. 2.67; p < 0.05). In total, the present in vitro study demonstrates the potential of clay minerals ingested with ruminant feeds for depressing the solubility of dietary Zn, as well as the depression of dietary Cu and Mn along the passage of the digesta from the rumen until the duodenum. Additionally, clay minerals may release Fe into the digesta.

A family of uranyl oxide hydrate phases with bivalent cations [MII(H2O)4][(UO2)3O3(OH)2]·H2O (MII – Mn, Co, Ni, Zn): synthesis, characterization and chemical stability in aqueous solutions

A series of new uranium compounds [MII(H2O)3][(UO2)3O3(OH)2]·2H2O (MII – Mn, Co, Ni, Zn) were synthesized for binding radionuclides in the environment and nuclear fuel cycle.

Screening of an Alkaline CMCase-Producing Strain and the Optimization of its Fermentation Condition

Objective: Alkaline Carboxymethyl Cellulase (CMCase) is an attractive enzyme for the textile, laundry, pulp, and paper industries; however, commercial preparations with sufficient activity at alkaline conditions are scarce. Methods: High CMCase-producing bacterial isolate, SX9-4, was screened out from soil bacteria, which was identified as Flavobacterium sp. on the basis of 16S rDNA sequencing. Results: The optimum pH and temperature for CMCase reaction were 8.0 and 55°C, respectively. Alkaline CMCase was stable over wide pH (3.0-10.6) and temperature (25-55°C) ranges. Enzyme activity was significantly inhibited by the bivalent cations Mn2+ and Cu2+, and was activated by Fe2+. To improve the alkaline CMCase production of SX9-4, fermentation parameters were selected through onefactor- at-a-time and further carried out by response surface methodologies based on a central composite design. Conclusion: High CMCase production (57.18 U/mL) was achieved under the optimal conditions: 10.53 g/L carboxymethylcellulose sodium, 7.74 g/L glucose, 13.71 g/L peptone, and 5.27 g/L ammonium oxalate.

Analysis of Environmental Performances of Ferritization Method for the Treatment of Copper-ammonia Wastewater under the Optimized Condition via RSM

Copper-ammonia wastewater from industrial processes is an important form of hazardous waste that can contaminate water resources. The conventional hydroxide precipitation method used to remove copper complexes produces a large volume of unstable precipitates which still require further treatment. Ferritization is a powerful technique to remove bivalent cations from wastewater in the form of metal ferrites. This method is highly efficient in removal of metal complex ions; in addition, sludge resulting from this method is stable. The objective of this study was to investigate optimum conditions for ferritization using Response Surface Methodology (RSM). After optimal conditions were determined, the environmental performance of ferritization compared with hydroxide precipitation was compared using Life Cycle Assessment (LCA) methodology. The IMPACT 2002+ method was used to calculate midpoints and damage levels. The experiment found that the model obtained from RSM was accurate and reliable with R2=98.37, Adj-R2=96.91, Pred-R2= 91.40, S=1.45 and PRESS =110.859. The optimal conditions for the pH, reaction temperature, and reaction time were found to be 10.8, 69 ºC, and 115 min, respectively. In addition, the actual experiment showed that the efficiency of copper-ammonia removal was 98.413.18%. The LCA results indicate that hydroxide precipitation shows more impact at midpoint levels than ferritization, except for aquatic acidification and global warming effects. On the other hand, the endpoint analysis showed that the ferritization has a higher performance in regard to human health, ecosystem quality, and resource consumption. Ferritization had a greater impact on climate change than hydroxide precipitation because the process requires electricity. Without the use of recycling sludge as catalyst, the endpoint of natural resources from ferritization could be higher than for hydroxide precipitation. In conclusion, ferritization demonstrated better performance both in terms of its efficiency of copper-ammonia removal and its environmental performance.

SPECIFIC FEATURES OF CLAY MINERALS IN ANCIENT CRUSTS OF WEATHERING OF VARIOUS ROCKS IN DIAMONDIFEROUS REGIONS

Results of complex research of different age ancient weathering crusts in various rocks (terrigenous-carbonate rocks of Lower Paleozoic, dolerites, tuffs and tufogene formations, kimberlites) within the main diamondiferous regions of the Siberian platform indicated that complicated multicomponent composition of initial formations (with the exception of terrigenous-carbonate rocks), containing di- and trioctahedral minerals, the structure of which has tri- and bivalent rock-forming elements, stipulated decelerated transformation of the initial material. Development of incomplete weathering profiles is first of all caused by weak ejection of bivalent cations from primary minerals. That is why newly emerging phases will be dioctahedral and often preserve mixed composition of cations. The most important typomorphic indications of clay formations in the studied weathering crusts are as follows: a) omnipresent dioctahedral hydromica (2М1) in the weathering crust of terrigenouscarbonate rocks and its association in the most mature profiles with kaolinite of relatively ordered structure, than of kaolinite, having been formed at the expense of other rocks; b) constant availability of trappean formation (tuffs, tufogene rocks, dolerites) in sections of crusts of weathering together with di- and trioctahedral montmorillonite, as well as disordered vermiculite-montmorillonite mixed-layered formation, to this or that degree disordered kaolinite, associated in the weathering crust of tufogene rocks with halloysite (at complete absence of micaceous minerals in the products of weathering); c) the content in the crust of weathering of kimberlites together with polycationic montmorillonite of a significant quantity of trioctahedral chlorite (packets δ and δ'), serpentine (structural types A and B) and altered to various degree phlogopite, including related with it hydromica 1M.