Search results for "Phosphorus"
showing 10 items of 431 documents
Analysis of pesticide residues in fruit and vegetables by matrix solid phase dispersion (MSPD) and different gas chromatography element-selective det…
1995
A comparison between different element selective detectors for the determination of organophosphorus and organochlorine pesticide residues, from fruit and vegetables, was performed by capillary GC with electron capture detector (ECD), nitrogen phosphorus detector (NPD), flame photometric detector (FPD) in the sulphur and phosphorus modes, and mass spectrometry detector (MSD) in selected ion monitoring (SIM) mode. Pesticides were extracted from the different foodstuffs by Matrix Solid Phase Dispersion (MSPD). Recoveries of 41–108 % with relative standard deviation of 2–14 % in the concentration range 0.5–10 μg L−1 were obtained in oranges, lemons, grapefruit, pears, plums, lettuces and tomat…
Etude par spectroscopies de RMN 23Na, 31P et 1H : effets de la teneur en sel (NaCl) dans des matrices alimentaires
2008
The reduction of salt (NaCl) content in food has become a matter of public health. However, the multiple functions of salt in food make the reduction of its content difficult. The aim of this work was to demonstrate the applicability of NMR innovative techniques in order to characterise the mobility of sodium ions (distinction between ‘free’ and ‘bound’ sodium), to bring a better understanding of the role of salt in the organisation of the food matrix (in particular phosphorous molecules in dairy systems) and to study impact of salt on the mobility of aroma compounds. In a first step, the 23Na NMR study of iota-carrageenan gels validated the quantification of total sodium (Single-Quantum, S…
Impacts of marine aquaculture at large spatial scales: evidences from n and p catchment loading and phytoplankton biomass
2011
International audience; While several studies point at off-shore aquaculture as a possible source of impacts on the local marine environment, very few have analysed its effects at large scales such as at the bay, gulf or basin levels. Similar analyses are hampered by the multiple sources of disturbance that may concomitantly affect a given area. The present paper addresses these issues taking the Gulf of Castellammare (Southern Tyrrhenian Sea) as an example. Nitrogen (N) and phosphorous (P) loads were calculated for the period 1970-2007, and compared to chlorophyll-a concentration as measured inside and outside the Gulf over the same period. Results indicate that N and P catchment loading h…
Influence of ferric iron dosing on aerobic granular sludge: granule formation, nutrient removal and microbial community
2021
BACKGROUND: Three lab-scale sequencing batch reactors were used to investigate the effects of Fe3+ on aerobic granular sludge (AGS) formation, nutrient removal, and microbial community. RESULTS: The addition of 6 and 12 mg Fe3+ L−1 could not shorten the granulation time. However, compared to the reactor without Fe3+ addition (average sludge volume index at 30 min (SVI30) 70.8 mL g−1; stable average particle size 548 μm), the addition of 12 mg Fe3+ L−1 helped improve the physical properties of AGS (average SVI30 57.0 mL g−1; stable average particle size 1067 μm). Furthermore, with 12 mg Fe3+ L−1 addition (Fe3+ to PO43−-P molar ratio = 1.33), effective removal of NH4+-N (≤0.5 mg L−1) and PO43…
Uncertainty of a biological nitrogen and phosphorus removal model
2010
In the last few years, the use of mathematical models in wastewater treatment plant (WWTP) processes has become a common way to predict WWTP behaviour. However, mathematical models generally demand advanced input for their implementation that must be evaluated by an extensive data gathering campaign, which cannot always be carried out. This fact, together with the intrinsic complexity of the model structure, leads to model results that may be very uncertain. Quantification of the uncertainty is imperative. However, despite the importance of uncertainty quantification, only a few studies have been carried out in the wastewater treatment field, and those studies only included a few of the sou…
Effect of pH on biological phosphorus uptake.
2006
An anaerobic aerobic laboratory scale sequencing batch reactor (SBR) was operated to study the effect of pH on enhanced biological phosphorus removal. Seven steady states were achieved under different operating conditions. In all of them, a slight variation in the pH value was observed during anaerobic phase. However, pH rose significantly during aerobic phase. The increase observed was due to phosphorus uptake and carbon dioxide stripping. When pH was higher than 8.2-8.25 the phosphorus uptake rate clearly decreased. The capability of Activated Sludge Model No. 2d (ASM2d) and Biological Nutrient Removal Model No. 1 (BNRM1) to simulate experimental results was evaluated. Both models success…
The influence of pulsed redox conditions on soil phosphorus
2010
Abstract. The effects of eleven pulsed reduction-oxidation cycles (20 and 2 days, respectively) on soil phosphorus (P) dynamics are compared for 12 soils having contrasting properties and overfertilised with respect to P. Incubation conditions simulated transient waterlogging of the soil profile and involved repeated sampling and analysis of both the solution and solid phase P forms. An initial increase in P concentration occurred upto and including the fourth full cycle was followed by a sharp decline in concentration for all but one soil. Accompanying changes in the main extractable forms of P, which appeared to be cumulative, could be summarised as a general decline in the organic P frac…
Effect of irrigation with treated wastewater on bermudagrass (Cynodon dactylon (L.) Pers.) production and soil characteristics and estimation of plan…
2022
In recent years, climate change has greatly affected rainfall and air temperature levels leading to a reduction in water resources in Southern Europe. This fact has emphasized the need to focus on the use of non-conventional water resources for agricultural irrigation. The reuse of treated wastewater (TWW) can represent a sustainable solution, reducing the consumption of freshwater (FW) and the need for mineral fertilisers. The main aim of this study was to assess, in a three-year period, the effects of TWW irrigation compared to FW on the biomass production of bermudagrass [Cynodon dactylon (L.) Pers.] plants and soil characteristics and to estimate the nutritional input provided by TWW ir…
Determination of organophosphate flame retardants in soil and fish using ultrasound-assisted extraction, solid-phase clean-up, and liquid chromatogra…
2017
A solid–liquid extraction method in combination with high‐performance liquid chromatography and tandem mass spectrometry was developed and optimized for extraction and analysis of organophosphorus flame retardants in soil and fish. Methanol was chosen as the optimum extraction solvent, not only in terms of extraction efficiency, but also for its broader analyte coverage. The subsequent clean‐up by solid‐phase extraction is required to eliminate matrix coextractives and reduce matrix effects. Recoveries of the optimized method were 50–121% for soil and 47–123% for biota, both with high precision (RSDs <12% in soil and <23% in biota). The method limits of detection ranged from 0.06 to 0.20 ng…
Enhancing extraction performance of organophosphorus flame retardants in water samples using titanium hierarchical porous silica materials as sorbent…
2021
Abstract A sorbent for the extraction of organophosphorus flame retardants has been proposed, based on UVM-7 (University of Valencia Materials) mesoporous silica doped with titanium. Designed cartridges have been applied to the extraction and preconcentration of flame retardants in water samples, followed by gas chromatography coupled to a mass spectrometry detector. Firstly, UVM-7 materials with different contents of titanium were synthesized and characterized by several techniques, thus confirming the proper mesoporous architecture. The potential of these materials was assessed in comparison with their morphological properties, resulting Ti50-UVM-7 the best solid phase. Several extraction…