Mixture based on peracetic acid and hydrogen peroxide is a more powerful oxidant than chlorine and chlorine dioxide. The reactivity of this oxidizing mixture with the polluting substances in the water: ammonium compounds, nitrites, iron, manganese, organic proteins is evaluated in this study. The results obtained after tasting this mixture, using various natural groundwater matrices shows an oxidation efficiency of over 90% of ammonium and nitrite content, between 40-70% of iron and 25-50% for manganese forms. The advantage of this oxidation mixture compared to thechlorine substances is that they do not form threehalomethane byproducts that have carcinogenic effect.
The viscosities of binary liquid mixtures of toluene with butan-1-ol and 2-methylpropan-2-ol have been determined at 298.15, 303.15, 308.15, 313.15 and 318.15 K over the whole concentration range. The Hind, Grunberg-Nissan, Wijk, Auslander and McAllister models were used to calculate the viscosity coefficients and these were compared with the experimental data for the mixtures. Excess viscosities were also calculated and fitted to the Redlich-Kister equation. Various thermodynamic properties of viscous flow activation were determined and their variations with composition are discussed.
Summary: Naturally abundant biosorbants such as chitin and chitosan are recognized as excellent metal ligands, forming stable complexes with many metal ions, and serving as effective protein coagulating agents. Chitosan is a heteropolymer made of D-glucosamine and a small fraction of N-acetyl-D-glucosamine residues. Therefore, the adsorption ability of chitosan is found to be much higher than that of chitin, which has relatively fewer amino groups. Zeolites are crystalline microporous aluminosilicates with ion exchange properties suitable for a wide range of applications in catalysis and separation of liquid and gaseous mixtures. Incorporation in chitosan membranes is an effective method to control the diffusion outside the zeolite crystals and appropriately designed composite systems can find numerous opportunities for applications in wastewater treatment. In this paper we present the synthesis of zeolite-chitosan and zeolite-ethyl cellulose composites by encapsulation of clinoptilolite using a gelling solution of chitosan or an ethyl cellulose solution in ethyl acetate. The adsorption process of Cu 2þ and Cd 2þ on some adsorbents was investigated: clinoptillolite tuff (0.05 mm), chitosan flakes, ethyl cellulose, zeolitechitosan and zeolite-ethyl cellulose composites. Zeolite-chitosan composites have been prepared by encapsulation of zeolites by a gelling solution of chitosan. Micrometric crystals of clinoptillolite were dispersed in a 3% chitosan solution in 1% aqueous acetic acid. The chitosan gel was formed and the zeolite crystals were encapsulated during the gelling process. The same procedure was used to obtain zeolite -ethyl cellulose composites. Study of the metal ion retention properties of different adsorbent materials was carried out using a steady state regime. The concentration of heavy metal ions in supernatant was determined by the atomic absorption spectrophotometric method. Adsorption isotherms of metal ions on adsorbents were determined and correlated with common isotherm equations such as Langmuir and Freundlich models.
The present work aims with the evaluation of copper, manganese and zinc concentrations (mobile forms) from vineyard soil before and after phytosanitary treatment with Curzate Manox and Dithane M-45 compounds, during and after remanence period. Different vineyard soils types were collected at 0-20 cm and 20-40 cm depths. Flame Atomic Absorption Spectroscopy (FAAS) method was used for measurements of the micronutrients. The soil samples were analyzed after 5 and 21 days after treatment application. Since copper is mainly accumulates in the upper layer following fungicidal sprays application, high levels of copper concentrations are obtained. The soil samples exhibits different behavior in terms of manganese and zinc contents. Manganese and zinc levels are classified as medium in the beginning of the experiment (Mn-M0 and Zn-M0), whereas these levels increased in the soil samples (at moments M1- 5 days and M2- 21 days after treatment). This behavior can be due to the Mancozeb decomposition, knowing that Mancozeb decomposes in the pH range 5-9 and it remains short time into the soil.
The efficiency of retaining ammonium on modified natural zeolites was investigated using a natural zeolite, the experimental program assuming the preparation of two types of ion exchangers that have been tested in the ammonium retaining process in comparison with the natural volcanic tuff by means of passage of NH4Cl solutions of 10 mmol/L concentration, respectively 5 mmol/L concentration. The graphical representations of the adsorption isotherms, as an indicator of the analyzed efficiency, performed using MATLAB� software programs, concluded that a modification of the natural tuff considerably improves the performances of the adsorbent material in the ammonium retaining process.
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