•Highest EC reduction occurred 20 days in both saline soils despite amendment type.•Ryegrass maximized Na discrimination in favor of K at 60 days in all soils.•Amendments are good pH buffer and ...nutrients sink even with soil salinization effect.
Synchronic and diachronic studies were carried out in order to examine the change of certain soil parameters with time after applying organic (green waste and sugarcane composts) and inorganic (gypsum at two rates) amendments on three soils with different salinity levels using ryegrass as the test crop during a 180-day incubation. The diachronic analysis involved the evaluation of the electrical conductivity dynamics over time. Maximum level of salinization has been observed when applying gypsum (both rates) for the non-saline soil, low gypsum rate (3.8 mg.g−1) for the saline soil, and sugarcane compost for the extremely saline soil. The maximum decrease in salinity was recorded at 120 days for non-saline soil and at 20 days for both saline and extremely saline soils. The synchronic study evaluated at the end of the incubation, showed a relative increase in electrical conductivity (EC) when applying gypsum (all rates) for non-saline soil, after applying green waste compost for the saline soil, and by applying high gypsum rate for extremely saline soil. This analysis also showed an increase in alkalinity and a decrease in organic matter, calcium, and magnesium. However, gypsum application showed, with regard to the other treatments, its effectiveness as a good mineralizer, pH neutralizer, and reservoir of Ca2+ when measured overtime. Maximum potassium uptake by ryegrass at the expense of sodium was obtained at day 60 of incubation, whereas, the highest absorption was not related as expected to the lowest EC whilst, optimum uptake levels were reached in the non-amended soil in the case of non-saline soil, high rate gypsum-amended soil for saline soil and low rate gypsum-amended soil for extremely saline soil.
Photocatalyzed degradation of phenol in aqueous solution over surface impregnated TiO2 (M = Cu, Cr, V) under UV-Vis (366 nm) and UV (254 nm) irradiation is described. Nanosized photocatalyts were ...prepared from TiO2-P25 by wet impregnation, and characterized by X-ray diffraction, X-ray fluorescence, transmission electron microscopy, UV-Vis diffuse reflectance spectroscopy, Raman spectroscopy, and adsorption studies. No oxide phases of the metal dopants were found, although their presence in the TiO2-P25 lattice induces tensile strain in Cu-impregnated TiO2-P25, whereas compressive strain in Cr- and V-impregnated TiO2-P25. Experimental evidences support chemical and mechanical stability of the photocatalysts. Type IV N2 adsorption–desorption isotherms, with a small H3 loop near the maximum relative pressure were observed. Metal surface impregnated photocatalysts are mesoporous with a similar surface roughness, and a narrow pore distribution around ca. 25 Å. They were chemically stable, showing no metal lixiviation. Their photocatalytic activity was followed by UV-Vis spectroscopy and HPLC–UV. A first order kinetic model appropriately fitted the experimental data. The fastest phenol degradation was obtained with M (0.1%)/TiO2-P25, the reactivity order being Cu > V >> Cr > TiO2-P25 under 366 nm irradiation, while TiO2-P25 > Cu > V > Cr, when using 254 nm radiation. TOC removal under 366 nm irradiation for 300 min showed almost quantitative mineralization for all tested materials, while 254 nm irradiation for 60 min led to maximal TOC removal (ca. 30%). Photoproducts and intermediate photoproducts were identified by HPLC–MS, and appropriate reaction pathways are proposed. The energy efficiency of the process was analysed, showing UV lamps are superior to UVA lamps, and that the efficiency of the surface impregnated catalyst varies in the order Cu > V > Cr.
A novel series of imidazopyridine Schiff bases have been synthesized by the acid-catalyzed reaction of 7-methyl-2-phenylimidazo1,2-
a
pyridin-3-amine with different aromatic aldehydes. The newly ...synthesized compounds were characterized by
1
H and
13
C NMR spectra and LC/MS data and screened for their antibacterial and antifungal activities against two bacterial strains (
Pseudomonas aeruginosa
and
Escherichia coli
) and one pathogenic fungal strain (
Fusarium oxysporum
f. sp.
Albedinis
) using disk diffusion method. Also, their antioxidant activity was evaluated using DPPH free radical scavenging method. Preliminary bioassay results showed that one of the synthesized compounds showed significant activity against the tested bacterial and fungal strains, while all the compounds displayed moderate antioxidant activities. The structure–activity relationship study revealed that the activity strongly depends on the substitution pattern. On the other hand, in silico ADME-Tox predictions and molecular docking studies were carried out to determine the bioavailability of the synthesized compounds and confirm the antifungal and antibacterial experimental findings.
A study is undertaken of the effect of fluorinating two TiO2 catalysts, both with the same surface area but one composed only of pure anatase phase (SA) and the other of mixed anatase and rutile ...phases (P25), on the degradation of phenol, formic acid and aniline. The catalysts were characterised by FTIR, BET, EDAXs, SEM, XRD and DRS-UV-vis studies. The method used for synthesis of the F-P25 and F-SA resulted in fluorinated catalysts with properties different to those of other fluorinated catalysts reported in the bibliography. The results obtained show that, unlike other studies in which the formation of free hydroxyl radicals (radical dotOHfree) was enhanced with the fluorinated catalysts, in the F-P25 and F-SA catalysts it was the formation of surface hydroxyl radicals (radical dotOHsurf) which was significantly enhanced. In this way, the F-P25 and F-SA catalysts gave rise to higher degradation rate constants of phenol (kphenol), aniline (kaniline) and formic acid (kformic) than the P25 and SA catalysts.
Purpose Soil salinization is one of the most severe abiotic stresses which threaten sustainable agriculture in arid and semi-arid regions including Morocco. The application of organic amendments like ...composts to saline soils has been confirmed to alleviate soil salinity stress. The present work aims to study the effect of humic acids (HA), as one of the products resulting from organic matter decomposition, on soil salinity reduction. Methods In this perspective, four composts made from mixtures corresponding to initial C/N ratios of 25, 30, 35 and 40 were tested. The four composts were made from mixtures of different proportions of greenhouse wastes, olive mill waste and sheep manure in Souss-Massa region. Representative samples underwent physicochemical analysis, extraction, purification and analysis of HA. The maturity of compost was assessed through some maturation index, prior to the main trial of the interaction between extracted HA and sodium carbonates salt (Na2CO3), largely encountered in saline soils. Results The results showed that the compost with initial C/N ratio of 35 is the most recommended for application as an amendment to alleviate soil salinity. Conclusion The salt stress alleviating effect of compost may be advocated to compost humic acids and their ability to chelate sodium on their carboxylic sites.
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