Adsorption of uranium(VI) onto <Emphasis Type="Italic">Ulva sp.</Emphasis>-sepiolite composite

Ulva sp. and sepiolite were used to prepare composite adsorbent. The adsorption of uranium(VI) from aqueous solutions onto Ulva sp.-sepiolite has been studied by using a batch adsorber. The parameters that affect the uranium(VI) adsorption, such as solution pH, initial uranium(VI) concentration, and temperature, have been investigated and the optimum conditions determined. The adsorption patterns of uranium on the composite adsorbent followed the Freundlich and Dubinin-Radushkevich (D-R) isotherms. The Freundlich, Langmuir, and Dubinin-Radushkevich (D-R) models have been applied and the data correlate well with Freundlich model. The sorption is physical in nature (sorption energy, E = 4.01 kJ/mol). The thermodynamic parameters such as variation of enthalpy ΔH, variation of entropy ΔS and variation of Gibbs free energy ΔG were calculated from the slope and intercept of lnK _d vs. 1/T plots. Thermodynamic parameters (ΔH _ads = −22.17 kJ/mol, ΔS _ads = −17.47 J/mol·K, ΔG ^o _ads (298.15 K) = −16.96 kJ/mol) show the exothermic heat of adsorption and the feasibility of the process. The results suggested that the Ulva sp-sepiolite composite adsorbent is suitable as a sorbent material for recovery and biosorption/adsorption of uranium ions from aqueous solutions.     

Assessment of different hazard indices around coal-fired power plants in Turkey

Journal of Radioanalytical and Nuclear Chemistry - This paper presents the radiological and heavy metal risk assessment to evaluate the impact of coal-fired power plants on humans and the...     

Comparison of trace metal concentrations in sediments and algae samples from the Küçükçekmece Lagoon and Marmara Sea

NAA has been applied to determine the concentration of K, As, Se, Zn, Cr, Cs, Fe, Co, Sb, Ni and Ca in sediments and a macroalgae species collected from the Küçükçekmece Lagoon and Marmara Sea. The lagoon sediment showed higher metal levels than the sea sediment. The metal contents in algae species are not changed significantly between months and sampling sites except Zn and Cr. The profile of the lagoon sediments was also investigated.     

The São Paulo School of Advanced Sciences (ESPCA) on Recent Developments in Synchrotron Radiation

The São Paulo School of Advanced Sciences (ESPCA) on Recent Developments in Synchrotron Radiation was held July 13–24, 2015, at the Brazilian Synchrotron Light Laboratory (LNLS) in Campinas, Brazil. The school was attended by 96 students, 48 from Brazil and 48 from 17 different countries. A total of 27 different nationalities were represented in this 12-day school. In addition, 22 lecturers presented 34 talks.     

Double exp-function method for multisoliton solutions of the Tzitzeica-Dodd-Bullough equation

Acta Mathematicae Applicatae Sinica, English Series - In this work, it is aimed to find one- and two-soliton solutions to nonlinear Tzitzeica-Dodd-Bullough (TDB) equation. Since the double...     

Solution Properties of Water-Soluble Nonionic Polymers

Abstract

Water-soluble nonionic polymers occupy a special place among synthetic polymeric materials. Most of them possess a number of unique properties allowing various industrial and medicinal applications. Such important industrial branches as coal mining, oil recovery, production of textiles, paper, lacquers, adhesives, cosmetics, and medicinal preparations cannot be conceived without these polymers. For instance, poly(acrylamide) and poly-(oxyethylene) can decrease pressure losses, increase considerably the drilling time, reduce the time of flooding underground spaces, and increase the speed of ship movement and pumping of liquids. Very important is the role of water-soluble nonionic polymers in the textile industry where they have successfully replaced expensive natural materials in the processes of cloth sizing and finishing and are used in the production of new kinds of fabrics possessing high mechanochemical characteristics. The use of these polymers is also important in medicine due to their good compatibility with water, high tendency to complex, and lack of toxicity.     

Phase equilibrium measurements of acoustically levitated squalane–CO2 mixtures by Raman spectroscopy

This work describes the phase equilibrium measurements of acoustically levitated binary mixtures with concentration measurements using Raman spectroscopy without sample extraction of the autoclave. The levitator design is implemented in a Single‐Droplet Optical Cell for levitation processes under varying atmospheres. The advantages of acoustic levitation of small droplets under increased temperatures and pressure combined with spectroscopic applications like Raman spectroscopy enable novel experiments possibly relevant to the fields of chemical engineering. To the author's knowledge, this is the first use of Raman spectroscopy for phase equilibria investigations on acoustically levitated droplets under high pressure and temperature. The results show very good agreements with literature data. Copyright © 2014 John Wiley & Sons, Ltd.     

A heat balance integral solution of the thermistor problem with a modified electrical conductivity

A key driver of thermistor response is a thermally-dependent electrical conductivity. Several variants have been proposed in the literature and it is the purpose of this paper to explore the applicability of a bulk model by way of using the heat balance integral approach to predict the response of a positive temperature coefficient thermistor. Conclusions are presented regarding the sensitivity of the response to electrical conductivity.