Decontamination Of Industrial Effluents Research Articles

THE USE OF ALUMINOSILICATE CLAYS AS SORBENTS IN THE PURIFICATION OF MEDIA FROM HEAVY METAL IONS

Shown that galvanic production, which is engaged in the application of protective or decorative coatings on metal and non-metal products (galvanizing, nickel plating, oxidation), can also be attributed to enterprises that pollute the environment with wastewater. Subject to all the norms of the technological process, despite the various methods of surface treatment of products, a certain amount of wastewater of complex composition is still formed. With an inferior degree of purification, they are one of the sources of pollution of aquatic environments. The main toxic components polluting this kind of wastewater are heavy metal ions such as chromium-6, cadmium-2, lead-2 and other toxic substances. Shown that in wastewater treatment the main place belongs to the sorption method, which uses natural sorbents such as activated carbons, zeolites, bentonite clays, and other natural materials. Searched for natural raw materials to obtain effective sorbents during decontamination of industrial effluents. The chemical-mineralogical composition of a number of deposits of aluminosilicate rocks in Azerbaijan has been studied. An analysis of the results obtained made it possible to establish the optimal variant of the synthesis of sorbents. Based on a frame-type aluminosilicate zeolite (clinoptilolite) and layered aluminosilicate (bentonite) with a high content of montmorillonite, their Na-forms were obtained. The results of the physicochemical analysis of the natural material and its modified Na-form are presented. Sorption treatment of wastewater from some heavy metal ions on modified forms of bentonite and clinoptilolite was carried out. It has been established that, in terms of sorption properties, the obtained sorbents based on natural raw materials Na-clinoptilolite and Na-bentonite can be recommended instead of synthetic industrial KU-2-8 in the sorption extraction of heavy metal ions from wastewater

Isolation of Fungi from a Textile Industry Effluent and the Screening of Their Potential to Degrade Industrial Dyes.

Six fungal strains were isolated from the textile industry effluent in which they naturally occur. Subsequently, the fungal strains were identified and characterized in order to establish their potential decolorizing effect on textile industry effluents. The strains of interest were selected based on their capacity to decolorize azo, indigo, and anthraquinone dyes. Three of the strains were identified as Emmia latemarginata (MAP03, MAP04, and MAP05) and the other three as Mucor circinelloides (MAP01, MAP02, and MAP06), while the efficiency of their decolorization of the dyes was determined on agar plate and in liquid fermentation. All the strains co-metabolized the dyes of interest, generating different levels of dye decolorization. Plate screening for lignin-degrading enzymes showed that the MAP03, MAP04, and MAP05 strains were positive for laccase and the MAP01, MAP02, and MAP06 strains for tyrosinase, while all strains were positive for peroxidase. Based on its decolorization capacity, the Emmia latemarginata (MAP03) strain was selected for the further characterization of its growth kinetics and ligninolytic enzyme production in submerged fermentation under both enzyme induction conditions, involving the addition of Acetyl yellow G (AYG) dye or wheat straw extract, and no-induction condition. The induction conditions promoted a clear inductive effect in all of the ligninolytic enzymes analyzed. The highest level of induced enzyme production was observed with the AYG dye fermentation, corresponding to versatile peroxidase (VP), manganese peroxidase (MnP), and lignin peroxidase (LiP). The present study can be considered the first analysis of the ligninolytic enzyme system of Emmia latemarginata in submerged fermentation under different conditions. Depending on the results of further research, the fungal strains analyzed in the present research may be candidates for further biotechnological research on the decontamination of industrial effluents.

A Study of the Removal Characteristics of Cu (II) Ions from Aqueous Solutions By a Low-Cost Adsorbent

Heavy metal pollution has become one of the most critical environmental problems throughout the world today, since they persist in the environment without degradation. Present study explores the feasibility of using Jak wood sawdust as a low cost adsorbent, for the removal of Cu(II) ions from aqueous solutions. Batch mode process was carried out to investigate the effect of contact time, initial metal concentration, particle size, pH and temperature with the dosage of 0.500 g sawdust treated with 0.1% sodium hydroxide. Maximum adsorption for Cu(II) was observed at pH 7 having the particle size 107-150 μm. Percentage removal of Cu(II) increased when temperature was varied from 20 C to 70 C. Langmuir, Freundlich and D-R isotherms were obtained at 30±0.2 C. Applicability of pseudo-first order, pseudo-second order, intra-particle diffusion and liquid-film diffusion kinetic models were investigated at 30±0.2 C. Cu(II) removal by Jack wood sawdust obeyed pseudo-second order kinetic model, Langmuir and D-R isotherms. Maximum removal capacity obtained from Langmuir and D-R isotherms are 6.26 and 5.51 mg g-1 respectively. Thermodynamic parameters ΔG, ΔS and ΔH obtained for the removal was (-) 8,52 kJmol-1 and 0.2 kJmol-1K-1 respectively indicating the removal process is favourable and spontaneous. IR analysis of sawdust before and after the removal of Cu(II) was carried out to identify the possible functional groups responsible for the removal and significant changes in the intensities of functional groups of metal loaded sawdust was observed with shifts in positions of some peaks. This research can be considered as a demonstration of using a waste material (sawdust) having a low economic value to solve an environmental problem such as decontamination of industrial effluents. Keywords: Jak wood sawdust, Copper removal

Comparative evaluations on bio-treatment of hexavalent chromate by resting cells of Pseudochrobactrum sp. and Proteus sp. in wastewater

Two marine bacterial strains, B5 and H24, were isolated from long-term Cr(VI) contaminated seawater and identified as Pseudochrobactrum and Proteus, respectively, based on 16S rRNA gene sequence analyses. Both strains were examined for their tolerance to Cr(VI) and other metal salts and their abilities to reduce Cr(VI) to trivalent chromium [Cr(III)]. Growing cells of Pseudochrobactrum sp. B5 and Proteus sp. H24 could tolerate Cr(VI) at a concentration of 2000 and 1500mg/l and completely reduce 1000mg/l Cr(VI) in LB medium within 96 and 144h, respectively. Resting cells of the two strains were able to reduce 200mg/l Cr(VI) in Tris–HCl buffer within 16 and 24h, respectively. Furthermore, resting cells of both strains were able to reduce Cr(VI) in industrial wastewaters three times consecutively. Overall, this study provides evidence of the potential for application of chromate-reducing bacteria to direct Cr(VI) decontamination of industrial effluents.

Reduction of hexavalent chromium by Streptomyces griseus

Hexavalent chromium (Cr 6+) is a common and toxic pollutant in soils and wastewaters. Conversion of the mobile Cr 6+ to less mobile and less toxic trivalent Cr 3+ can be achieved with conventional chemical reduction and its subsequent precipitation. Alternatively, Cr 6+ can also be reduced to Cr 3+ by microorganisms and has potential for application in decontamination of industrial effluents. During our studies on chromium toxicity in actinomycetes, a strain of Streptomyces griseus was found to grow and reduce highly toxic Cr 6+ to less toxic Cr 3+ from media containing 5–60 ppm of Cr 6+. The concentration of Cr 3+ increased with simultaneous decrease in Cr 6+ during growth with complete conversion in 3–4 days. Reduction was faster when addition of chromium (especially high concentrations of chromium) was done after 24 h growth than at the time of inoculation. Conversion of Cr 6+ to Cr 3+ was complete within 24–48 h of chromium addition with significant uptake in the biomass. Reduction of chromium by resting cells and effect of various factors on chromium reduction are discussed.