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1.
Mouheb Sboui Mohamed Faouzi Nsi Ali Rayes Meenakshisundaram Swaminathan Ammar Houas 《环境科学学报(英文版)》2017,29(10):3-13
A novel photocatalyst based on TiO_2–PANI composite supported on small pieces of cork has been reported. It was prepared by simple impregnation method of the polyaniline(PANI)–modified TiO_2 on cork. The TiO_2–PANI/Cork catalyst shows the unique feature of floating on the water surface. The as-synthesized catalyst was characterized by X-ray diffraction(XRD),scanning electron micrograph(SEM), transmission electron microscopy(TEM), thermogravimetric analysis(TGA), Fourier transform infrared spectroscopy(FT-IR), UV–vis diffuse reflectance spectra(UV–vis DRS) and the Brunauer–Emmett–Teller(BET) surface area analysis. Characterization suggested the formation of anatase highly dispersed on the cork surface. The prepared floating photocatalyst showed high efficiency for the degradation of methyl orange dye and other organic pollutants under solar irradiation and constrained conditions, i.e., no-stirring and no-oxygenation. The TiO_2–PANI/Cork floating photocatalyst can be reused for at least four consecutive times without significant decrease of the degradation efficiency. 相似文献
2.
M. Wiens B. Luckas F. Brümmer M. Shokry A. Ammar R. Steffen R. Batel B. Diehl-Seifert H. Schröder W. Müller 《Marine Biology》2003,142(2):213-223
Sponges are sessile filter feeders that are exposed to toxic compounds/xenobiotics and a huge number of diverse pro- and eukaryotic organisms occurring in the aqueous milieu. To cope with these threats, sponges have developed a variety of chemical and immunological defense systems. Among them are potent secondary metabolites or toxins. The demosponge Suberites domuncula contains the bioactive compound okadaic acid; concentrations of ᅢ ng/g (ᅬ nM) of wet tissue have been quantified by LC/MS. In the present study, we sought to determine whether okadaic acid is beneficial for this sponge. Antibodies were raised against okadaic acid and used to localize this compound in situ. It could be demonstrated that the polyclonal antibodies/antiserum stained the sponge cells (endopinacocytes) which form the epithelium of the lacunae and the water channels. They also reacted with bacteria present in sponge tissue. Okadaic acid was found to augment the immune response of S. domuncula against the bacterial endotoxin lipopolysaccharide (LPS). If primmorphs, a special form of 3-D aggregates, are incubated with LPS at a concentration of 3 µg/ml, a reduction in the incorporation rate of [3H] phenylalanine is measured. In the presence of okadaic acid, this effect is measured already at a concentration of 1 µg/ml, suggesting that okadaic acid sensitizes this (immune) response. Okadaic acid is a known inhibitor of protein phosphatases which, as shown here, cause an increased phosphorylation of p38, a central kinase of the MAP kinase pathway; this may explain the sensitive response of the sponge cells to LPS. At higher concentrations, okadaic acid induces apoptosis, as was demonstrated here by a differential expression of the Bcl-2 homolog and the caspase gene. It is concluded that okadaic acid has two functions in the sponge; first, at low concentrations (<100 nM) a stimulation of the defense system against bacteria, and second, at concentrations above 500 nM, a differential effect on the pro-/anti-apoptotic genes. 相似文献
3.
Natija Barhoumi Nihal Oturan Salah Ammar Abdellatif Gadri Mehmet A. Oturan Enric Brillas 《Environmental Chemistry Letters》2017,15(4):689-693
There is actually increasing concern about the accumulation of antibiotics, such as tetracycline, in soil and water bodies. There is therefore a need for efficient methods to degrade antibiotics and thus clean waters. Here we tested the degradation of tetracycline using the heterogeneous electro-Fenton-pyrite method and compared the results with the conventional electro-Fenton method. The reaction was performed with a boron-doped diamond or Pt anode and carbon-felt cathode allowing electrogeneration of H2O2 from O2 reduction. Results show an increasing tetracycline mineralization using the following methods: anodic oxidation with electrogenerated H2O2, electro-Fenton and then electro-Fenton-pyrite using boron-doped diamond. Ion-exclusion HPLC revealed the complete removal of malic malonic, succinic, acetic, oxalic and oxamic acids. Nitrogen present in tetracycline was mainly mineralized in NH4 +. The higher efficiency of electro-Fenton-pyrite is explained by self-regulation of soluble Fe2+ and pH to 3.0 from pyrite catalyst favoring larger ·OH generation from Fenton’s reaction. 相似文献
4.
Salah Ammar Ridha Abdelhedi Cristina Flox Conchita Arias Enric Brillas 《Environmental Chemistry Letters》2006,4(4):229-233
Here we demonstrate that anodic oxidation with a boron-doped diamond (BDD) electrode can be applied to the remediation of wastewaters containing indigo carmine. This environmentally friendly method decontaminates completely acid and alkaline aqueous solutions of this dye. The degradation rate increases with increasing current and dye concentration. Indigo carmine is more rapidly removed in alkaline than in acid medium, but its kinetics does not follow a defined reaction order. Isatin 5-sulfonic acid is the main aromatic product formed. Oxalic and oxamic acids are generated as ultimate carboxylic acids. The nitrogen of the dye is converted into NH4
+ and NO3
−. 相似文献
5.
This paper presents a dynamic temperature model for a proton exchange membrane fuel cell (PEMFC) system. The proposed model overcomes the complexity of conventional models using first-order expressions consisting of load current and ambient temperature. The proposed model also incorporates a PEMFC cooling system, which depends upon the temperature difference between events. A dynamic algorithm is developed to detect load changing events and calculate instantaneous PEMFC temperature variations. The parameters of the model are extracted by employing the lightning search algorithm (LSA). The temperature characteristics of the NEXA 1.2 kW PEMFC system are experimentally studied to validate model performance. The results show that the proposed model output and the temperature data obtained from experiments for linear and abrupt changes in PEMFC load current are in agreement. The root-mean-square error between the model output and experimental results is less than 0.9. Moreover, the proposed model outperforms the conventional models and provides advantages such as simplicity and adaptability for low and high sampling data rates of input variables, namely, load current and ambient temperature. The model is not only helpful for simulations but also suitable for dynamic real-time controllers and emulators. 相似文献
6.
7.
Abd Ammar Ali Othman Mohd Roslee Kim Jinsoo 《Environmental science and pollution research international》2021,28(32):43329-43364
Environmental Science and Pollution Research - The atmosphere security and regulation of climate change are being continuously highlighted as a pressing issue. The crisis of climate change owing to... 相似文献
8.
Friha Hadj Ammar Najiba Chkir Kamel Zouari Zohra Azzouz-Berriche 《Journal of environmental radioactivity》2010,101(9):681-691
The distributions of 238U and 234U in groundwater from the “Jeffara aquifer” were studied by using alpha spectrometric methods. The concentration ranges of 238U and 234U/238U activity ratios were 1.34 ± 0.17 to 3.43 ± 0.38 ppb, and 1.43 ± 0.23 to 1.82 ± 0.27 respectively. Variations in concentrations can be related not only to lithostratigraphic formations but also to different origins of groundwater. U content of Jeffara are found very similar to those of Continental Intercalaire aquifer in both El Hamma and Chenchou regions, indicating that the Continental Intercalaire is the dominant source of the groundwater. 相似文献
9.
Muhammad Al-Zahrani Ammar Musa Shakhawat Chowdhury 《Environment, Development and Sustainability》2016,18(3):777-798
A multi-objective goal programming model was developed for water distribution from multiple sources to multiple users. The model was applied in Riyadh, Saudi Arabia, for the period of 2015–2050. In Riyadh, water sources are groundwater (GW), desalinated water (DW) and treated wastewater (TWW), while the users are domestic, agricultural and industrial sectors. The model was applied to: (1) satisfy water demands and quality; (2) maximize TWW reuse and GW conservation; and (3) minimize overproduction of DW and overall cost. In 2015, the required allocations of GW, DW and TWW are 3286, 662 and 609 MCM, respectively, which are projected to be 4345, 1554 and 1305 MCM in 2050, respectively. GW source is likely to satisfy the predicted withdrawal of GW till 2035, while probabilities of non-satisfaction of full demands of GW in 2040, 2045 and 2050 were 0.04, 0.23 and 0.51, respectively. Supply of DW and reuse of TWW are needed to be increased to satisfy the predicted quantities during 2015–2050. 相似文献
10.
Phytoremediation potential of Arabidopsis thaliana, expressing ectopically a vacuolar proton pump, for the industrial waste phosphogypsum 总被引:1,自引:0,他引:1
Habib Khoudi Yafa Maatar Faïçal Brini Amine Fourati Najoua Ammar Khaled Masmoudi 《Environmental science and pollution research international》2013,20(1):270-280
Phosphogypsum (PG) is a by-product of the phosphorus–fertiliser industry and represents an environmental concern since it contains pollutants such as cadmium (Cd). We have recently shown that the overexpression of a proton pump gene (TaVP1) in transgenic tobacco (Nicotiana tabacum) led to an enhanced Cd tolerance and accumulation. The aim of this study was to evaluate the potential of transgenic Arabidopsis thaliana plants harbouring the TaVP1 gene to phytoremediate phosphogypsum. A pot experiment was carried out under greenhouse conditions. Transgenic A. thaliana plants harbouring the TaVP1 gene were grown on various substrates containing phosphogypsum (0, 25, 50 and 100 %) for 40 days. At the end of the growth period, we examined the growth (germination, root length, fresh weight) and physiological parameters (chlorophyll and protein contents, catalase activity and proteolysis) as well as the cadmium, Mg, Ca, and P contents of the A. thaliana plants. In order to evaluate Cd tolerance of the A. thaliana lines harbouring the TaVP1 gene, an in vitro experiment was also carried out. One week-old seedlings were transferred to Murashige and Skoog agar plates containing various concentrations of cadmium; the germination, total leaf area and root length were determined. The growth and physiological parameters of all A. thaliana plants were significantly altered by PG. The germination capacity, root growth and biomass production of wild-type (WT) plants were more severely inhibited by PG compared with the TaVP1 transgenic A. thaliana lines. In addition, TaVP1 transgenic A. thaliana plants maintained a higher antioxidant capacity than the WT. Interestingly, elemental analysis of leaf material derived from plants grown on PG revealed that the transgenic A. thaliana line accumulated up to ten times more Cd than WT. Despite its higher Cd content, the transgenic A. thaliana line performed better than the WT counterpart. In vitro evaluation of Cd tolerance showed that TaVP1 transgenic A. thaliana lines were more Cd-tolerant than the WT plants. These results suggested that ectopic expression of a vacuolar proton pump in A. thaliana plants can lead to various biotechnological applications including the phytoremediation of industrial wastes. 相似文献