Inorganic Technology and Environmental Protection

Levels of nitrates in groundwater in some instances are above the safe levels proposed by the EPA and thus
pose a threat to human health. Passive groundwater remediation using permeable reactive barriers (PRBs)
is a new and innovative technology for the removal of pollutants from groundwater. It acts as barrier against
its contaminants, and removes them by adding an adsorption material for contaminants or a reactive material,
able to interact with contaminants and diminish their bio-availability. In this paper, it was tried to find the
best way to remove nitrate (NO3
-) ion from water using elemental iron according to water pH and water
temperature. The results of the experiments were processed using an Artificial Neural Network (ANN) in
order to create a mathematical model capable to predict the optimum quantity of iron needed to remove
nitrate ion from the polluted water with nitrates in a given concentration. The present study analyses ANN as
a mean to predict the nitrate ion removal from contaminated water. The parallel and distributed structure of
artificial neural networks with their capabilities of generalization, fault tolerance, adaptive and associative
performance, ability to perform dynamic and real-time functions, and their limited requirement of software,
ensure their appropriateness for much practical environmental application.

În acest studiu, a fost cercetată electrocoagularea colorantului acid Albastru 25 în soluţie apoasă utilizând aluminiu ca anod de sacrificiu. Experimentele au fost realizate pentru o concentraţie iniţială de 5x10-5M. Performanţele procesului de electrocoagulare au fost evaluate pe ...

Bulletin UASVM Agriculture, 67(2)/2010 Print ISSN 1843-5246; Electronic ISSN 1843-5386 ... Removal of Nitrate and Hexavalent Chromium from Groundwater Using Zerovalent Iron – A Laboratory Study ... Cristina MODROGAN 1) , Alexandra R. MIRON 2) , Oanamari D. ORBULET 3) ,

In the present work, the mass transfer characteristics such as the lenght of mass transfer unit (LMTU), the break through time and column saturation time have been studied in the case of sulphur dioxide adsorption on 13 X zeolite. The adsorption column was working in unsteady-state conditions. For these determinations a chromatographic method has been used, permiting the direct inregistration of breakthrough curves, whose shape depends on adsorption conditions (gas concentration, temperature, the size of adsorbent grains, gas velocity). The method is very sensitive, reflecting all changes of adsorption parameters.

The adsorption of cadmium and zinc ions from waste waters in agricultural argilaceaus soils have been studied, using a thermodynamic method in order to put in evidence the influence of adsorption conditions on adsorption degree. The adsorption isotherms, Langmuir and Freundlich, have been used to describe the adsorption equilibrium. The experimental data put in evidence that Cd2+ ions are more adsorbable (about 300 mmol/g) than Zn2+ ones (about 200 mmol/g). The Langmuir isotherms reflect more exactly the adsorption process of both Cd2+and Zn2+ ions, being recommended for thermodynamic parameters determination.

This work is devoted to examine the effectiveness of the different commercial liquid additives for fish (sweet corn and molasses) on corrosion of mild steel in natural water by different methods (gravimetric and potentiostatic polarization) at room temperature. The corrosion tests were employed to evaluate corrosion rate (CR) and inhibition efficiency (IE %). The maximum inhibition efficiency was obtained for the inhibitor type molasses of 90.00% by gravimetric method for a period of 3 hours and over 31 % by potentiostatic polarization method. It was found that the commercial liquid additives acted as a good inhibitors for the tested environment. Furthermore, the corroded metal was observed by metallographic microscope.

Understanding the absorption behaviour of sulphur dioxide in aqueous electrolyte solutions is of major interest for the design of flue gas desulphurization processes, as for example wet flue gas desulphurization of coal fired power plants or municipal solid waste incineration plants. In the present paper the influence of the water salinity on SO2 absorption is studied. The SO2 absortion was performed in equilibrium condition. The variation of marine solubility from 10 g/L to 40 g/L determines the variation of SO2 concentration in water from 2.6 mol/L to about 3.2 mol/L. In consequence, the variation of water salinity in these limits can detemine a quite big difference of water pollution.

The aim of this work is the study of te adsorption process of some heavy metals like lead, copper, chrome and nickel in agricultural argilaceous soil in order to put in evidence the influence of adsorption conditions on adsoption process. The adsorption isotherms, Langmuir and Freundlich, have been used to describe the adsorption equilibrium. The experimental data put in evidence that the adsoption capacity of heavy metals increases in order Ni2+ (about 110 micromol/g), Pb2+ (about 150 micromol/g), Cr3+ (about 300 micromol/g) and Cu2+(about 350 micromol/g). In all cases, the Langmuir isotherm reflects more exactly the adsorption process, being recomended for thermodynamic parameters determination.

A novel hydrogel composite based on gellan gum and graphene oxide (GG/GO) was synthesized, characterized and tested for sorption capacity in this work. The microstructural, thermogravimetric and spectroscopic analysis confirmed the formation of the GG/GO composite. Comparative batch sorption experiments revealed a sorption capacity of the GG/GO composite for Zn (II) ions of approximately 2.3 higher than that of pure GG. The GG/GO composite exhibits a maximum sorption capacity of 272.57 mg/g at a pH of Zn (II) initial solution of 6. Generally, the sorption capacity of the sorbents is approximately 1.5 higher in slightly acidic conditions (pH 6) comparative with that for strong acidic conditions (pH 3). The sorption isotherms revealed that the sorption followed a monolayer/homogenous behavior. The sorption kinetic data were well fitted by the pseudo-second-order kinetic model, and were consistent with those derived from sorption isotherms. The intraparticle diffusion was considered to...

The realization of some composite materials that allow the best removal of H2S from syngas was the main objective of this work. Thus, the optimization of the technological parameters for obtaining composites based on Zn-Ti was achieved. The paper studies the influence of calcination temperature on the characteristics of the binary ZnO-TiO2 system used to synthesize a composite material with suitable properties to be used subsequently for syngas treatment. The mineralogical and structural analyzes showed that starting with the calcination temperature of 700 °C the material synthetized is composed mainly of zinc orthotitanate which possess the corresponding characteristics to be finally used in the treatment of the syngas for its desulfurization. At this calcination temperature the material has a compact structure most likely due to sintering of the formed titanates. These composites have a texture that places them rather in the category of non-porous materials, the pore volume and th...

The present paper synthesized, characterized, and evaluated the performance of the novel biopolymeric membrane enriched with cellulose acetate and chitosan (CHI)-silver (Ag) ions in order to remove iron ion from the synthetic wastewater using a new electrodialysis system. The prepared membranes were characterized by Fourier Transforms Infrared Spectroscopy-Attenuated Total Reflection (FTIR-ATR), Thermal Gravimetric Analysis (TGA) and Differential Thermal Analysis (DSC), contact angle measurements, microscopy studies, and electrochemical impedance spectroscopy (EIS). The electrodialysis experiments were performed at the different applied voltages (5, 10, and 15 V) for one hour, at room temperature. The treatment rate (TE) of iron ions, current efficiency (IE), and energy consumption (Wc) were calculated. FTIR-ATR spectra evidenced that incorporation of CHI-Ag ions into the polymer mixture led to a polymer-metal ion complex formation within the membrane. The TGA-DSC analysis for the o...