Phosphorus recovery and leaching of trace elements from incinerated sewage sludge ash (ISSA).

Chemical extraction of phosphorus (P) from incinerated sewage sludge ash (ISSA) is adversely influenced by co-dissolution of metals and metalloids. This study investigated P recovery and leaching of Zn, Cu, Pb, As and Ni from ISSA using inorganic acids (sulphuric acid and nitric acid), organic acids (oxalic acid and citric acid), and chelating agents (ethylenediaminetetraacetic acid (EDTA) and ethylene diamine tetramethylene phosphonate (EDTMP)). The aim of this study was to optimize a leaching process to recover P-leachate with high purity for P fertilizer production. The results show that both organic and inorganic acids extract P-containing phases but organic acids leach more trace elements, particularly Cu, Zn, Pb and As. Sulphuric acid was the most efficient for P recovery and achieved 94% of total extraction under the optimal conditions, which were 2-h reaction with 0.2 mol/L H2SO4 at a liquid-to-solid ratio of 20:1. EDTA extracted only 20% of the available P, but the leachates were contaminated with high levels of trace elements under optimum conditions (3-h reaction with EDTA at 0.02 mol/L, pH 2, and liquid-to-solid ratio of 20:1). Therefore, EDTA was considered an appropriate pre-treatment agent for reducing the total metal/metalloid content in ISSA, which produced negligible changes in the structure of ISSA and reduced contamination during subsequent P extraction using sulphuric acid.

Evaluation of polyphenolic profile and nutritional value of non-traditional fruit species in the Czech Republic--a comparative study.

Dry matter, organic acids, ascorbic acid, minerals (nitrogen, phosphorus, potassium, calcium, magnesium, sodium) and polyphenolic profile of a number of non-traditional fruit species and their genotypes, namely blue honeysuckle (Lonicera spp.), Saskatoon berry (Amelanchier alnifolia), black mulberry (Morus nigra), Tomentosa cherry (Prunus tomentosa Thunb.) and jostaberry (Ribes nigrum x Grossularia uva-crispa) were investigated. The results showed that Lonicera genotypes displayed high levels of ascorbic acid and they were rich in minerals, with the cultivar 'Amfora' achieving the leading position in nitrogen, phosphorus and potassium content among all lesser known fruit species. Amelanchier cultivars represented a valuable source of ascorbic acid and calcium, 'Tisnovský' and 'Smoky' together with Morus nigra 'Jugoslavska' accumulated the highest level of examined polyphenolic compounds. Regular consumption of studied less common fruit species can bring health benefits so they can represent a high potential value for fruit growers and in addition they can be utilised as functional foods.

The hepatotoxicity of multi-walled carbon nanotubes in mice.

The hepatotoxicity of two types of multi-walled carbon nanotubes (MWCNTs), acid-oxidized MWCNTs (O-MWCNTs) and Tween-80-dispersed MWCNTs (T-MWCNTs), were investigated with Kunming mice exposed to 10 and 60 mg kg(-1) by intravenous injection for 15 and 60 d. Compared with the PBS group, the body-weight gain of the mice decreased and the level of total bilirubin and aspartate aminotransferase increased in the MWCNT-exposed group with a significant dose-effect relationship, while tumor necrosis factor alpha level did not show significant statistical change within 60 d. Spotty necrosis, inflammatory cell infiltration in portal region, hepatocyte mitochondria swelling and lysis were observed with a significant dose-effect relationship in the MWCNT groups. Liver damage of the T-MWCNT group was more severe than that of the O-MWCNT group according to the Roenigk classification system. Furthermore, T-MWCNTs induce slight liver oxidative damage in mice at 15 d, which was recovered at 60 d. Part of the gene expressions of mouse liver in the MWCNT groups changed compared to the PBS group, including GPCRs (G protein-coupled receptors), cholesterol biosynthesis, metabolism by cytochrome P450, natural-killer-cell-mediated cytotoxicity, TNF- alpha, NF-kappaB signaling pathway, etc. In the P450 pathway, the gene expressions of Gsta2 (down-regulated), Cyp2B19 (up-regulated) and Cyp2C50 (down-regulated) had significant changes in the MWCNT groups. These results show that a high dose of T-MWCNTs can induce hepatic toxicity in mice while O-MWCNTs seem to have less toxicity.

Trace determination and chemical speciation of selenium in environmental water samples using catalytic kinetic spectrophotometric method.

A catalytic kinetic method is described for the determination of Se(IV), Se(VI) and total inorganic selenium in water based on the catalytic effect of Se(IV) on the reduction of bromate by hydrazine dihydrochloride in acidic media. The generated bromine decolorized methyl orange (MO) and the reaction was monitored spectrophotometrically at 507 nm as a function of time. The initial rate and fixed time methods were adopted for the determination and speciation of inorganic selenium. Under two optimum conditions, the calibration graphs are linear in the range 0-126.3 and 0-789.6 microg L(-1) of Se(IV) for the initial rate method and 0-315.8 and 0-789.6 microg L(-1) of Se(IV) for the fixed time method. The detection limits were 1.3 and 14.7 microg L(-1) for the initial rate and fixed time methods, respectively. The proposed methods were validated statistically and through recovery studies in environmental water samples. The relative standard deviation in the determination of 31.6-94.8 microg L(-1) of Se(IV) and Se(VI) was less than 6%. Analyses of standard reference materials for selenium using initial rate and fixed time methods showed that the proposed methods have good accuracy. Se(IV), Se(VI) and total inorganic selenium in environmental water samples have been successfully determined by this method after selective reduction of Se(VI) to Se(IV).

Epoxidation of cottonseed oil by aqueous hydrogen peroxide catalysed by liquid inorganic acids.

The kinetics of epoxidation of cottonseed oil by peroxyacetic acid generated in situ from hydrogen peroxide and glacial acetic acid in the presence of liquid inorganic acid catalysts were studied. It was possible to obtain up to 78% relative conversion to oxirane with very less oxirane cleavage by in situ technique. The rate constants for sulphuric acid catalysed epoxidation of cottonseed oil were in the range 0.39-5.4 x 10(-6)L mol(-1)s(-1) and the activation energy was found to be 11.7 kcal mol(-1). Some thermodynamic parameters such as enthalpy, entropy, and free energy of activation were determined to be of 11.0 kcal mol(-1), -51.4 cal mol(-1)K(-1) and 28.1 kcal mol(-1), respectively. The order of effectiveness of catalysts was found to be sulphuric acid>phosphoric acid>nitric acid>hydrochloric acid. Acetic acid was found to be superior to formic acid for the in situ cottonseed oil epoxidation.

New method of treating dilute mineral acids using magnesium-aluminum oxide.

Mineral acids, such as H(3)PO(4), H(2)SO(4), HCl, and HNO(3,) were treated with magnesium-aluminum oxide (Mg-Al oxide), which behaved as a neutralizer and fixative of anions. Anion removal increased with increasing Mg-Al oxide quantity, time, Mg/Al molar ratio, and initial acid concentration. Up to 95% removal of anions was achieved in 0.5 N acids using a stoichiometric quantity of Mg(0.80)Al(0.20)O(1.10) for H(3)PO(4), 1.75 stoichiometric quantities for H(2)SO(4), or 2.5 stoichiometric quantities for HCl or HNO(3) at 20 degrees C over a period of 6 h. The final solutions were found to have a pH in the range of 8-12. Selectivity of acid removal was found to follow the following order: H(3)PO(4) > H(2)SO(4) > HCl > HNO(3). The equivalent of acid removal per 1 g of Mg-Al oxide decreased as the Mg/Al molar ratio of Mg-Al oxide increased.