Effect of radial impeller size in the presence and absence of baffles on the copper exchange on zeolite NaX

Effect of hydrodynamics on ion exchange in a batch reactor is still not appropriately studied even though proper mixing parameters may considerably affect the process of solid suspension and its costs. In this work, hydrodynamic conditions generated by straight blade turbine (SBT) impellers on suspension in the batch reactor with and without baffles were investigated. The aim of this work was to analyze influence of impeller diameter and zeolite mass on just suspended impeller speed, (NJS) power consumption, maximum amount of copper exchanged onto zeolite NaX and copper exchange kinetics as well. All experiments were conducted at the same temperature, initial concentration of the copper solution and zeolite particle size. The obtained results showed that just suspended impeller speed decreases as impeller diameter increases in the reactor with and without baffles but this trend is considerably more pronounced in the reactor with baffles. The increase in zeolite mass causes a slight increase of NJS in the both reactor. In the reactor with the baffles this increment became noticeably higher as impeller diameter decrease. Power consumption, at the state of complete zeolite suspension, decreases as impeller diameter increases and its values in the reactor without baffles are considerably lower as well. Kinetics results indicated that the amount of copper ion increases significantly in the initial stage and then gradually until the equilibrium is reached for all hydrodynamics conditions and mass of zeolite examined.

Comprehensive Analysis of the Copper Exchange Implemented in Ammonia and Protonated Forms of Mordenite Using Microwave and Conventional Methods

This article presents the results of a comprehensive study of copper-exchanged mordenite samples prepared from its ammonia and protonated forms (Si/Al = 10) using two different ion exchange methods: conventional and microwave (MW)-assisted. The protonated H-MOR-10 sample was obtained by calcination of commercial NH4MOR-10; in this case, a slight degradation of the mordenite framework was observed, but the resulting defects were partially restored after the first ion-exchange procedure of protons for copper ions. The level of copper exchange in the studied materials was found to be limited to 70%. Regardless of the exchange procedure, the replacement of ammonium or proton ions with copper led to a linear increase in the a/b ratio of cell parameters in accordance with an increase in the level of copper exchange, which means that all Cu2+ cations are ion-exchangeable and enter the main mordenite channel. Thermal analysis indicated a correlation between the replacement of various ammonium and hydroxyl groups by copper ions during the exchange treatment and their dehydroxylation energy during thermal decomposition. As a conclusion: MW-assisted treatment proved itself as an efficacious method for the synthesis of copper-exchanged mordenites, which not only significantly reduces preparation time but leads to a systematically higher copper exchange level.

The copper content in the organs and tissues of Mytilus galloprovincialis Lamarck, 1819 and the flow of its sedimentary deposition into bottom sediments in the farms of the Black Sea aquaculture

The role of mussels in formation of water chemical composition is determined by the peculiarities of sorption and trophodynamic processes. Copper is a vital element, but of ten metals the toxic effect of which was tested for the survival of mussel and oyster embryos, copper is following mercury. Studying the regularities of copper content change during mussel ontogeny allows to determine both sanitary and hygienic risks of mussel product use during the mollusks cultivation in mariculture and the biogeochemical role in the formation of the chemical composition of the marine water near mussel farms. The purpose of this work is to determine the copper content in the organs and tissues of the mussels during seasonal course of mollusks ontogenesis, to analyze the degree of copper assimilation along the food path of mineral nutrition using the mathematical model and empirical data and to assess the influence of marine farms on the copper exchange processes in the coastal ecosystem. The mollusks were collected from the mussel farm located in the external roadstead of Sevastopol. Studying the copper content in the environment – mussel – biodeposition system, a method of atomic absorption spectroscopy with electrothermal atomization was used. A general model illustrating the process of copper exchange between the mussels and the water environment is presented. Equations for determining the degree of assimilation of metal from food (q) and the limiting coefficient of food accumulation of metal (Кп) are proposed based on the results of measurements of its concentrations in the mussels’ diet, soft tissue and their biodeposition without using radioactive trace elements. The values of the copper removal by the mussel farm were calculated. The role of cultivated mollusks in the heavy metals precipitation was shown.