A series of S-glucosides 11a-14a and their benzamido derivatives 11b-14b have been synthesized by reacting D-glucose with thiol groups of 5-(2'-aminophenylene)-1,3,4-oxadiazole-2-thioles 7(a,b), 5-(2'-aminophenylene)-1,3,4-thiadiazole-2-thiols 8(a,b), 5-(2'-aminophenylene)-1,2,4-triazole-3-thiols 9(a,b) and 5-(2'-aminophenylene)-4-N-amino-1,2,4-triazole-3-thiols 10(a,b). The thiols 7(a,b)-10(a,b) have been synthesized from hydrazides 3(a,b) which already been synthesized from 2-aminobenzoic acid and its benzamido derivative. All synthesized compounds were characterized by IR, UV, 1 H-and 13 C-NMR. Nucleobases and a representative of S-glycoside were tested in vitro against the following microorganisms: two Gram-positive bacteria Staphylococcus aureus and Bacillus cereusand two Gram-negative bacteria Escherichia coli, Pseudomonas aeruginosa and they exhibited significant effects. Amykacine was used as positive standard.

A bacterial strain Pseudomonas aeruginosa isolated from an uncontaminated soil has been used for the removal of hexavalent chromium (Cr (VI)). The experiments were carried out in batch system in a culture broth. The results obtained have shown that 100% of Cr (VI) are removed. Contact time, initial concentration of the hexavalent chromium, temperature, as well as the nature of the culture broth have influenced this elimination. To the initial concentration of 20g/L of Cr (VI) the elimination rates are lower, while the reverse occurs for an initial concentration of 8g/L. This study allows considering the use of Pseudomonas aeruginosa in the treatment of water polluted by toxic heavy metals such as Cr (VI).

The removal of lead from aqueous solutions was studied using the liquid-solid extraction method. The solids used are the crude phosphocalcic hydroxapatite [Ca10(PO4)6(OH)2] (HAPc), and phosphocalcic hydroxapatite treated with 5 % lactic acid solution (HAPal). The extraction results showed the influence of the initial concentration of Pb (II) and temperature of the suspensions. The maximum adsorption capacities of each material (HAPc and HAPal) were obtained with the application of Langmuir adsorption model. The most important quantity was founded as 41,84mg/g for HAPal. Isotherms established at different temperatures showed that this parameter affects greatly the adsorption of Pb (II) on both adsorbents. The best results were obtained at room temperature (25°C) compared with those recorded at 50°C.Finally, the results of this study allow us to note that the hydroxiapatite material can be as good extractant solid, for heavy metals, especially when it is modified with lactic acid.

The removal process of Cr(III) in aqueous solution using activated sludge as adsorbent was optimized. Response surface methodology was employed to assess the removal efficiency considering the cumulative effect of pH and contact time. The quantitative relationship between Cr(III) uptake and variable parameters was used to optimize the control level of each parameter by a full factorial design method. The analysis of variance demonstrates that the model was statistically highly significant, which shows also that the removal of Cr(III) was affected by the studied factors. The model was statistically tested and verified by experimentation. The response surface methodology gives not only valuable information on interactions between the evaluated parameters but also allows identifying the optimum values of the studied factors.

Hexavalent chromium is one of the hazardous metals that can be found in industrial effluents such as wood treatment units, mining, leather tanning, pigment, steel and electroplating industry. The present work aimed to evaluate the self-purification capacity of the microbial flora taken from the domestic wastewater effluent of Chlef City, with the perspective of designing a microbial bed in the secondary sewage treatment to prevent an industrial Cr(VI) contamination. Under various operating conditions, the bioremoval performance of Cr(VI) was evaluated by using suspended biomass and immobilised biomass (fixed onto pozzolana grains).The results showed that the immobilised biomass was more efficient and more resistant to Cr(VI) toxicity than the suspended biomass. Indeed, the Cr(VI) was totally eliminated within 96 h for an initial concentration of 50 mg l −1 by the immobilised biomass, while this rate was obtained after 120 h for the suspended biomass. The kinetic data fit well to the pseudo-first order kinetic model. The intraparticle diffusion kinetic model suggested that the diffusion process of Cr(VI) was greatly influenced by the initial concentration. The microbial flora present in domestic wastewater is a promising biosorbent that is able to treat effluent containing Cr(VI).