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1

A study of grain size effect on radon exhalation rate and uranium content of a phosphate rock

Jabbade Meryame, Nachab Abdellatif, Nourreddine Abdel Mjid, Errami Ezzoura, Benjelloun Mohammed

Acta Geophysica

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2022

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Vol. 70, no 6

2805--2812

EN

Assessment of the exhalation rate allows a classification of materials according to their potential risk of exposure to radon. The present study investigates the granulation effect on the radon exhalation rates from a phosphate sample. The phosphate sample was sieved into different grain size dimensions ranging from2 mm. The exhalation rate of each fraction was measured using the accumulation method. The radon exhalation rate was found to decrease with an increase in grain size above 0.125 mm. The influence of grain size on uranium content was also studied using the autoradiography method. The uranium concentration increased for the smallest grains (0.5 mm). The measured values of radon exhalation rates are under the limits reported worldwide.

2

Vertical migrations in an Alpine grassland cambisol after long-term sewage sludge application

Sager M.

Ecological Chemistry and Engineering. S

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2017

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Vol. 24, nr 1

141--158

EN

Differences between vertical mobilities of nutrient and trace elements within a long-term sludge-treated and an adjacent untreated Alpine grassland cambisol were investigated by column experiments. The site had been intensely fertilized with urban sewage sludge for 10 years of 7.5 Mg/ha annually, whereas an adjacent site had been left untreated. A model column experiment was set up to investigate changes of permeabilities and trace element retentions at 0-20 cm and 20-60 cm layers thereof. Elution was performed with de-ionized water at amounts of expected rainfall at the sampling site (1000 mm), as well as with equal volume of manure after biogas production. Long-term sludge treatment increased organic carbon, formation of ammonium and nitrate, and increased vertical mobility of K, P, S, Cu, and Fe, but also slightly higher (below 10-fold) for Na, Sr, Ba, Ni and V. Additional application of manure was of minor effect, mainly upon nitrate formation, and upon leaching of Fe, Mn as well as Fe/Mn proportion. Prior addition of FeCl2 to the manure in order to increase sulfide precipitation, mainly affected the output of ammonia, but hardly the cations or anions (e.g. P) investigated.

3

Phosphate recovery from animal manure wastewater by struvite crystallization and CO2 degasification reactor

Zhang T., Li P., Fang C., Jiang R.

Ecological Chemistry and Engineering. S

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2014

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Vol. 21, nr 1

89--99

EN

The problem of phosphorus discharge is related to environmental protection and food security. Struvite crystallization is a useful technology for phosphate recovery from wastewater. In the research, struvite crystallization process with CO2 degasification continuous U-shape reactor (CUSR) was application for phosphate recovery from animal manure wastewater. The result indicated PO43--P recovery ratio could achieve 47-53% without magnesium addition when CUSR hydraulic retention time controlled at 60 min. With extra magnesium addition, PO43--P recovery ratio could significant achieve 80-86% at magnesium addition amount 57.5 mg/dm3. PHREEQC modeling predictions trend of struvite crystallization was close to CUSR experimental results. The modeling calculation can provide a theoretical guide for operational parameters design. For seeding technology, high phosphate recovery efficiency was obtained and preformed struvite was the most effective seeding material. Surface characterization analysis demonstrated the dominant composition of chemical solids was struvite. Water extraction analysis indicated chemical solids recovery from animal manure wastewater could release PO43--P slowly and be available as slow-release fertilizer.

PL

Problem uwalniania fosforu jest związany z ochroną środowiska i bezpieczeństwem żywności. Krystalizacja struwitu jest przydatną technologią odzysku fosforanów ze ścieków. W opisanych badaniach proces krystalizacji struwitu zastosowano do odzyskiwania fosforanów z gnojowicy, do tego celu wykorzystano reaktor ciągłego odgazowywania CO2 w kształcie litery U (CUSR). Wyniki wskazują, że wskaźnik odzysku PO43- może osiągnąć 47-53% P bez dodatku magnezu, gdy kontrolowany, hydrauliczny czas retencji CUSR wynosi 60 min. Po wprowadzeniu magnezu w ilości 57,5 mg/dm3 wskaźnik odzysku PO43- może osiągnąć 80-86% P. Przewidywania modelu PHREEQC dotyczące krystalizacji struwitu był bliskie wynikom doświadczalnym CUSR. Obliczenia teoretyczne z wykorzystaniem modelu mogą stanowić wskazówkę do ustalania rzeczywistych parametrów eksploatacyjnych. Struwit otrzymany z gnojowicy może mieć zastosowanie w nasiennictwie. Analiza ekstrakcyjna wykazała, że materiał ten może powoli uwalniać PO43-P i dzięki temu znajduje zastosowanie jako nawóz.

4

Phytoplankton extracellular phosphatases: Investigation using the ELF (enzyme labelled fluorescence) technique

Strojsova Alena, Vrba Jaroslav

Polish Journal of Ecology

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2006

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Vol. 54, nr 4

715-723

EN

Phosphorus deficiency is frequently the limiting factor in phytoplankton growth and the major source of selective pressure on single populations in a variety of aquatic environments. Phytoplankton species have several mechanisms that allow them to overcome phosphorus starvation, such as high-affinity uptake of orthophosphate (Pi), stand-by energy metabolism or utilization of phosphorus from stored polyphosphates. This short review is focused on the production of extracellular phosphatases that is usually accompanied by high-affinity uptake of Pi. Extracellular phosphatases are localized on thecell membrane, where they catalyze the liberation of Pi from various organic compounds that are too large to be directly transported into the cell. The production of extracellular phosphatases is not a general response to starvation in phytoplankton; it is a species-specific or cell-specific feature. The ELF (Enzyme Labelled Fluorescence) technique enables direct visualization of the sites of enzymatic activity and therefore gives detailed information about the physiological status of natural phytoplankton.

5

The mechanical strength of phosphates under friction-induced cross-linking

Pawlak Z., Yarlagadda P. K. D. V., Frost R., Hargreaves D.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 17, nr 1-2

201--204

EN

Purpose: In the present study, we consider mechanical properties of phosphate glasses under high temperature-induced and under friction-induced cross-linking, which enhance the modulus of elasticity. Design/methodology/approach: Two nanomechanical properties are evaluated, the first parameter is the modulus of elasticity (E) (or Young’s modulus) and the second parameter is the hardness (H). Zinc meta-, pyro - and orthophosphates were recognized as amorphous-colloidal nanoparticles were synthesized under laboratory conditions and showed antiwear properties in engine oil. Findings: Young’s modulus of the phosphate glasses formed under high temperature was in the 60-89 GPa range. For phosphate tribofilm formed under friction hardness and the Young’s modulus were in the range of 2-10 GPa and 40-215 GPa, respectively. The degree of cross-linking during friction is provided by internal pressure of about 600 MPa and temperature close to 1000°C enhancing mechanical properties by factor of 3 (see Fig 1). Research limitations/implications: The addition of iron or aluminum ions to phosphate glasses under high temperature - and friction-induced amorphization of zinc metaphosphate and pyrophosphate tends to provide more cross-linking and mechanically stronger structures. Iron and aluminum (FeO4 or AlO4 units), incorporated into phosphate structure as network formers, contribute to the anion network bonding by converting the P=O bonds into bridging oxygen. Future work should consider on development of new of materials prepared by sol-gel processes, eg., zinc (II)-silicic acid. Originality/value: This paper analyses the friction pressure-induced and temperature–induced the two factors lead phosphate tribofilm glasses to chemically advanced glass structures, which may enhance the wear inhibition. Adding the coordinating ions alters the pressure at which cross-linking occurs and increases the antiwear properties of the surface material significantly

6

Assessment of pollution by heavy metals and polycyclic aromatic hydrocarbons of surface water in Kampinos National Park

Oprządek K., Syrocka K., Kluska M., Kroszczyński W., Zalewski W.

Archiwum Ochrony Środowiska

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2004

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Vol. 30, no. 3

27--34

EN

Some natural and anthropogenic properties of surface water were investigated in National Park of Kampinos in years 2000-2002. Obtained results were compared with corresponding standards. Analyses of samples of water revealed most of them to be adequate to the 1 class of purity. Benzo(a)pyrene was not detected. However, in two cases high concentration of iron and manganese was observed. As a rule, the samples collected in November exhibited higher concentration of manganese. In one case high concentration of nitrates was determined. Most of samples collected in Aleksandrów met the requirement for the II class of purity because of phosphate concentration.

PL

W latach 2000-2002 badano niektóre naturalne i antropogenne właściwości wód powierzchniowych Kampinoskiego Parku Narodowego. Uzyskane wartości średnie omówiono w porównaniu do odpowiednich norm. Analizy większości próbek wykazały, że odpowiadają one I klasie czystości. Benzo(a)pirenu nie wykryto. Jednak w dwóch przypadkach zaobserwowano wysokie stężenie żelaza i manganu. Próbki pobrane w listopadzie zawierały więcej manganu. W jednym przypadku oznaczono wysokie stężenie azotanów. Większość próbek pobranych w Aleksandrowie odpowiadała 11 klasie czystości ze względu na zawartość fosforanów.

7

Abatement of chromate and phosphate from wastewater

Kowalski Z., Konopka M.

Polish Journal of Chemical Technology

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2001

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Vol. 3, nr 2

8-10

EN

This work presents the results of the model research on treatment of the wastewater which contains both chromate and phosphate ions. Co-removing of the phosphate and chromate ions from the wastewater was realised with the method of reduction of Cr exp.6+ with iron (II) salts and precipitation as chromium hydroxide. It is possible to decrease the CrO4 exp.2 and PO4 exp2 concentration to a level below 0.01 ppm. The solid phase (filter cake) contained quantitatively precipitated ions of trivalent metals and phosphate and partially precipitated sulphate and calcium ions.