Fractionation of soil phosphorus in a long-term phosphate fertilization

The changes in inorganic and organic phosphorus (P) fractions of soil resulting from long-term fertilization (40 years) were investigated. In order to improve understanding of the sink and sources of phosphorus, P-fractions were extracted from soil samples of 0-30 and 30-60 cm depth with different amounts of monoammonium-phosphate (MAP) and then determined. Stagnosol was the type of the studied soil. Phosphate fertilizer was applied in 26, 39 and 52 kgP/ha amounts during the period of 40 years. Samples were subjected to sequential extraction according to the modified Chang and Jackson method and BCR (Community Bureau of Reference) sequential extraction procedure in order to extract different forms of phosphorus. The Certified Reference material CRM 684 (River Sediment Extractable Phosphorus) was used to provide accuracy of the instrument and both used methods. Furthermore, the association of phosphorus with substrates was provided by comparison of the results of sequential methods of phosphorus species with the sequential extraction of metals (Fe, Al, Mn and Ca). Results of continuous fertilization during 40 years indicated the increase of all the phosphorus forms in the soil except of phosphorus bound to calcium and organic phosphorus. Application of higher amounts of P-fertilizer resulted in dominance of Al-P fraction in studied soil which indicated that this fraction was the most responsible for the migration of phosphorus along the soil profile

Degradation of benzodiazepines using water falling film dielectric barrier discharge reactor

Classical methods of wastewater treatment are often not suitable for the treatment of pharmaceutical waste. The previous studies have shown that the use of the advanced oxidation procedures (AOP) can lead to a more efficient degradation of various biologically active compounds, which are active pharmaceutical ingredients of applied drugs. The aim of this paper is the application of the plasma technology on the degradation of a two active pharmaceutical ingredients (APIs, diazepam and alprazolam) and the finished products (Bensedin((R)) and Ksalol((R))) using the dielectric barrier discharge (DBD) reactor for AOP. We studied the degradation rate of these pharmaceuticals, depending on the number of passes through the reactor. This degradation method was efficient 61 % for diazepam and 95 % alprazolam. We also examined the influence of the pH adjustment between the passes of APIs through the DBD reactor. The degradation rate of APIs and the finished products was monitored by the high performance liquid chromatography (HPLC) technique, using a photodiode array detector. The concentration of the dissolved ozone was determined using the iodometric procedure

New evidence for TiO2 uniform surfaces leading to complete bacterial reduction in the dark: Critical issues

This study presents new evidence for the events leading to Escherichia coil reduction in the absence of light irradiation on TiO2-polyester (from now on TiO2-PES. By transmission electron microscopy (TEM) the diffusion of TiO2 NP's aggregates with the E. coil outer lipo-polyssacharide (LPS) layer is shown to be a prerequisite for the loss of bacterial cultivability. Within 30 min in the dark the TiO2 aggregates interact with E. coil cell wall leading within 120 min to the complete loss of bacterial cultivability on a TiO2-PES 5% TiO2 sample. The bacterial reduction was observed to increase with a higher TiO2 loading on the PES up to 5%. Bacterial disinfection on TiO2-PES in the dark was slower compared to the runs under low intensity simulated sunlight light irradiation. The interaction between the TiO2 aggregates and the E. coil cell wall is discussed in terms of the competition between the TiO2 units collapsing to form TiO2-aggregates at a physiologic pH-value followed by the electrostatic interaction with the bacteria surface. TiO2-PES samples were able to carry repetitive bacterial inactivation. This presents a potential for practical applications. X-ray photoelectron spectroscopy (XPS) evidence was found for the reduction of Ti4+ to Ti3+ contributing to redox interactions between TiO2-PES and the bacterial cell wall. Insight is provided into the mechanism of interaction between the E. coil cell wall and TiO2 NP's. The properties of the TiO2-PES surface like percentage atomic concentration, TiO2-loading, optical absorption, surface charge and crystallographic phases are reported in this study. (C) 2014 Elsevier B.V. All rights reserved

Sponge-like europium oxide from hollow carbon sphere as a template for an anode material for Reactive Blue 52 electrochemical degradation

The textile industry is one of the major pollutants of waterbodies with effluents high in biochemical and chemical oxygen demand values, high values of total dissolved solids, total suspended solids, and low dissolved oxygen values along with strong color. The existence of a successful method for its decontamination would be beneficial. In this work, we synthesized sponge-like europium oxide (Eu2O3) using a template-directed route from carbon hollow spheres, obtained from glucose as a carbon source. The material synthesis method was done in an aqueous environment, without using any organic solvents. Electrochemical properties of the synthesized material were investigated using cyclic voltammetry and electrical impedance spectroscopy, while morphological characterization was done using scanning electron microscopy and X-ray powder diffraction analysis. Eu2O3 were successfully immobilized at the surface of a screen-printed carbon electrode (Eu2O3/SPCE) using the drop-casting method. Finally, the prepared electrodes were tested toward the removal of Reactive Blue 52 (RB52) using electrochemical advanced oxidation processes (EAOPs). Important parameters, that is, the supporting electrolyte, its concentration, pH value, and the applied voltage, were optimized for RB52 degradation. The rate of removal was monitored spectrophotometrically and by high-performance liquid chromatography with a diode array detector (HPLC-DAD). It was found that the proposed approach reaches complete decolorization of the RB52 solution after a 60-min treatment, at pH 5.6 of KC1 supporting electrolyte at a concentration of 0.05 M. Under optimal parameters, after 3 h of treatment, total organic carbon (TOC) was lowered by similar to 40%. The obtained results indicate that the proposed method may find potential application in EAOPs, considering electrode stability, durability, and efficiency and simplicity of the method

Fe Doped TiO₂ Prepared by Microwave-Assisted Hydrothermal Process for Removal of As(III) and As(V) from Water

Elevated concentrations of arsenic in groundwater, which is used as a source for drinking water, is a worldwide problem. Use of TiO₂ and iron doped TiO₂ synthesized by a microwave-assisted hydrothermal method for As­(III) and As­(V) removal were examined. Synthesized sorbents were characterized with XRD and nitrogen physisorption. Synthesized sorbents have predominantly anatase structure, and no peaks for iron could be observed. Doping of iron increases the surface area of synthesized sorbents. Sorption experiments show that increase of iron in sorbents increases the sorption capacity for As­(III) and As­(V). Increase of pH from 3 to 11 has no influence on As­(III) sorption but decreases the sorption of As­(V). Batch isotherm studies were performed to determine the binding capacities of As­(III) and As­(V). As­(III) followed the Freundlich isotherm model, while for As­(V) a better fit was with the Langmuir isotherm. The results of competition of SO₄^2– and PO₄^3– anions on adsorption of As­(III) indicated that both anions reduced substantially the efficiency of adsorption on both adsorbents while for As­(V) only the presence of PO₄^3– anion interfered with adsorption. Testing 10Fe/TiO₂ sorbent with arsenic contaminated natural water showed that this material could be used for removal of arsenic to the level recommended by WHO without pretreatment