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The present study was carried out to investigate three different adsorbents; dry cells of the bacterium Exiguobacterium sp. 27, polyaniline and a mixture of both in different ratios for removal of Ni(II) from aqueous solution. The results showed that the adsorption of Ni(II) using dry cells of Exiguobacterium sp. 27 was very fast and the equilibriu...
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... k 2 represents the pseudo-second-order model rate constant (g mol −1 min −1 ).The values of k 2 and R 2 values are provided inTable 2. The correlation coefficient R 2 value of the pseudo-second order model in (PVA-PANI/10-GO) NF and (PVP/PVA-PANI/10-CS) NF (0.9996 and 0.9998) is better than the pseudo-first order model ( Figs. 11 B1, B2)[40] . ...
Polyvinyl alcohol-polyaniline/graphene oxide nanofiber (PVA-PANI/GO)NF and polyvinyl pyrrolidone/polyvinyl alcohol-polyaniline/chitosan nanofiber (PVP/PVA-PANI/CS)NF were prepared by mixing PANI with GO suspension and CS solution respectively using different amounts (1, 10 wt %), and followed by electrospinning and nanofibers were created using a proportion (1:2) mixture of PVP and PVA, where the PVA was used to improve the viscosity and the PVP was utilized to boost the conductivity of the nanocomposite. X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier Transform Infrared Spectroscopy (FTIR) were used to characterize the produced materials. The adsorbents (PVA-PANI/GO)NF and (PVP/PVA-PANI/CS)NF are used to remove Ni (II) from aqueous solution. Several variables were investigated in order to compare (PVA-PANI/GO)NF and (PVP/PVA-PANI/CS)NF removal efficiency and adsorption capacity, such as contact time, concentration, dose quantity, and temperature. Langmuir and Freundlich adsorption isotherm models were used to describe the equilibrium isotherm and the adsorption followed Freundlich adsorption isotherm. Nickel ion adsorption kinetics on (PVA-PANI/GO)NF and (PVP/PVA-PANI/CS)NF follow a pseudo second-order kinetic model.
... Water pollution with heavy metals remains a significant environmental issue due to its negative impact on health and ecosystems [1]. Nickel ions exist in the environment by small concentration; however, a high concentration of nickel ions has a negative effect on the human due to its toxicity. ...
... The correlation coefficient R 2 of the pseudo-first-order model (Fig. 11A) was found to be 0.9242, the calculated equilibrium adsorption capacities (q e values) were tabulated in Table 2. The straight-line of the pseudo-firstorder model was not valid in all contact time Fig. 11A [1,55]. ...
Polyaniline/carbon quantum dots (PANI/CQDs) nanocomposites were synthesized by simple interfacial polymerizations of aniline followed by adding different contents of carbon quantum dots (1,10 wt. %) to the polyaniline. The resulting (PANI/CQDs) nanocomposites were impregnated by dimethylgyloxime (DMG) and used as adsorbent to remove nickel. The nanocomposites were characterized using different techniques such as X-rays diffraction (XRD), scanning electron microscopy (SEM), and Fourier Transform Infrared Spectroscopy (FTIR). A highly ordered crystalline nanosheets structure of PANI decorated by CQDs completely coated with DMG is obtained. The developed PANI/CQDs/DMG nanocomposite using 1,10 wt. % of CQDs have a high adsorption capacity of 290.3 and 245 mg/g, respectively. Several effects were studied to optimize the removal efficiency. Thermodynamic parameters such as entropy changes, enthalpy changes, and Gibbs free energy were evaluated. The adsorption kinetics of Ni (II) ions onto PANI/10-CQDs/DMG follows the second-order kinetic model. The adsorption isotherm models followed Langmuir isotherm. The developed promised nanocomposite is cheap, has high adsorption capacity, and reusable.
... Adsorption of Cr(VI) onto PANI was determined by the increase in intensity of the peak at 1005.2 cm −1 while in composites the same was observed at 1039.6 cm −1 as reported elsewhere [57,58]. Similar results were obtained after adsorption of Ni(II) on all adsorbent materials, however; shifting of % transmittance was less as compared to Cr(VI), indicating stronger interactions between Cr(VI) and adsorbent materials as compared to Ni(II) [59]. FTIR results correlated to the results obtained from EDX and UV-visible spectroscopy. ...
Water pollution caused by industrial wastes containing heavy metals and dyes is a major environmental problem. This study reports on the synthesis, characterization, and utilizations of Polyaniline (PANI) and its composites with Fe3O4 for the removal of hexavalent chromium Cr(VI) and divalent nickel Ni(II) ions from water. The adsorption data were fitted in Freudlich, Langmuir, Tempkin, Dubbanin–Ruddishkawich (D–R), and Elovich adsorption isotherms. The Freundlich isotherm fits more closely to the adsorption data with R2 values of 0.9472, 0.9890, and 0.9684 for adsorption of Cr(VI) on Fe3O4, PANI, and PANI/Fe3O4 composites, respectively, while for adsorption of Ni(II) these values were 0.9366, 0.9232, and 0.9307 respectively. The effects of solution pH, initial concentration, contact time, ionic strength, and adsorbent dosage on adsorption behavior were investigated. The adsorption ability of composites was compared with pristine PANI and Fe3O4 particles. Activation energy and other thermodynamic properties such as changes in enthalpy, entropy, and Gibbs free energy indicated spontaneous and exothermic adsorption.
... There are several conventional methods by which heavy metals can be removed from aqueous solution of their compounds. These methods includes; Chemical precipitation, electro dialysis, coagulation/flocculation, ultrafiltration, reverse osmosis, and adsorption being very simple, economical, effective and versatile has become the most preferred method for removal of toxic contaminants from wastewater (Amer et al, 2014) [15] . Recently, one of the important chelating agents receiving an increased interest recently due to the presence of defined chelating group is Schiff bases. ...
In this study, a Schiff base N,N-Dibenzylidene-ethane-1,2-diamine derived from ethylenediamine and Benz aldehyde was successfully prepared and used as adsorbent for the removal of Cu(II) and Ni(II) ions from their aqueous solutions in batch mode. Batch optimization parameters were studied at the equilibrium time of 60 minutes for both Ni (II) and Cu (II). Residual metal ion concentration where determined using atomic absorption spectrometry. Effect of initial metal ion concentration showed that they give higher % removal at 200 mg/L. The adsorption kinetics revealed the metal ions were adsorbed satisfactorily obeying Pseudo second order model with R 2 values of 0.984 and 0.989 for Ni (II) and Cu (II) respectively. The optimum pH value obtained was 4 for both Cu (II) and Ni (II). Langmuir isotherm model fitted well with the experimental data showing the process is chemisorption. The calculated R L values of the metal ions 0.0036 for Ni (II) and 0.0055 for Cu (II) revealed the adsorption process being favourable. The calculated heat of adsorption values of 106.0 J/mol for Ni (II) and 961.7 J/mol for Cu (II) also showed that the adsorption of the metal ions onto the synthesized Schiff base is a chemical process.
... Some strains of Exiguobacterium spp. show the ability to remove various heavy metals from contaminated environments, allowing them to be used in bioremediation (Alam and Ahmad 2013;Amer et al. 2014;Pandey and Bhatt 2015). In addition, Exiguobacterium undae YR10 showed a great potential to immobilize Cd in soil due to the production of urease and dehydrogenase, enzymes that can convert Cd to CdCO 3 (Kumari et al. 2014). ...
Brown mud, as a waste product of the industrial process of aluminum production, represents a great environmental burden due to its toxicity to living organisms. However, some microorganisms are able to survive in this habitat, and they can be used in bioremediation processes. Traditional cultivation methods have a limited capacity to characterize bacterial composition in environmental samples. Recently, next-generation sequencing methods have provided new perspectives on microbial community studies. The aim of this study was to analyze the bacterial community in the drainage water of brown mud disposal site near Žiar nad Hronom (Banská Bystrica region, Slovakia) using 454 pyrosequencing. We obtained 9964 sequences assigned to 163 operational taxonomic units belonging to 10 bacterial phyla. The phylum Proteobacteria showed the highest abundance (80.39%) within the bacterial community, followed by Firmicutes (13.05%) and Bacteroidetes (5.64%). Other bacterial phyla showed an abundance lower than 1%. The classification yielded 85 genera. Sulfurospirillum spp. (45.19%) dominated the bacterial population, followed by Pseudomonas spp. (13.76%) and Exiguobacterium spp. (13.02%). These results indicate that high heavy metals content, high pH, and lack of essential nutrients are the drivers of a dramatic reduction of diversity in the bacterial population in this environment.
... Although there are several techniques available to remove heavy metals from aqueous solutions, adsorption is the most widely used one due to its high effectiveness, low operational cost, and universality (Ali, 2014;Ali, 2012;Gupta, 2006, Rao et al., 2006). Recent examples of such studies include the adsorption of lead (II), copper (II), zinc (II), nickel (II), cadmium (II), chromium (VI), and arsenic in both transitional forms (III, V) using a variety of adsorbents rather than activated carbon where the authors have reinforced the applicability of this technique (Ileri et al., 2014;Amer et al., 2014;Abd El fatah and Ossman, 2014;Amiri et al., 2014;Andjelkovic et al., 2014). Therefore, from a waste management point of view, this study made an effort to recycle the ROFA volume in order to prepare activated carbon by physical activation methods which could be used as adsorbents of heavy metals in industries. ...
In this study, the recycling possibility of residual oil fly ash (ROFA) towards preparing activated carbon and its application in environmental remediation through adsorbing Cu (II) and Pb (II) ions from aqueous solutions were investigated. Activated carbons were prepared using two different physical activation methods such as under steam flow at 950 0C, and combined steam and CO2 flow at 850 0C for 2 hours. Characterization of activated carbons was done by BET surface area method, scanning electron microscopy (SEM), Fourier transform infra-red spectroscopy (FTIR), and X-ray diffraction technique (XRD). Combined gasification increased the surface area of ROFA particles quite higher (110.89 to 423.09 m 2 /g) than only steam activation (275.07 m 2 /g). Development of microporosity was also achieved during the treatments and it increased from 0.043 cc/g (raw ash) to 0.325 in steam activated samples, and 0.078 in combined gas activated samples. FTIR analysis showed the presence of aromatic, ester, and hydroxyl functional groups on the ROFA surface after the treatment while XRD examination confirmed its carbonaceous and amorphous nature. pH 5 was found optimum for the adsorption studies at which the removal efficiencies were >71% for Cu (II) and >80% for Pb (II), while the concentration was 25 ppm for both metals. The Langmuir isotherm model was found statistically significant for both Cu (II) (R 2 > 0.95) and Pb (II) (R 2 > 0.99). ROFA has been successfully recycled in this work and the activated carbons might be considered for industrial applications.
... Some biosorbents such as Acacia leucocephala (Subbaiah et al., 2009), Azadirachta indica (Bhattacharyya et al., 2009), Bacillus pumilus (Wierzba and Latala, 2010), Exiguobacterium sp. (Amer et al., 2014), Elaeagnus Angustifolia (Amiri et al., 2014), Mucor hiemalis (Shroff and Vaidya, 2011), Pseudomonas fluorescens (Wierzba and Latala, 2010), Pseudomonas sp. (Gialamouidis et al., 2009), Rhodococcus opacus (Cayllahua et al., 2009), Salvadora persica L. branches (Ileri et al., 2014), Staphylococcus xylosus (Gialamouidis et al., 2009), Streptomyces rimosus (Selatnia et al., 2004), and grapefruit peel (Torab-Mostaedi et al., 2013) have been used to remove Ni(II) ions from the aqueous solutions. ...
This paper discusses the biosorption of Ni(II) ions from aqueous solutions by Bacillus sphaericus biomass. The biosorption process was affected by the solution pH, biomass concentration, contact time, temperature and initial Ni(II) concentration respectively. The sorption kinetics and equilibrium data were described well with the pseudo-second order kinetic model and the Freundlich isotherm model. The maximum monolayer biosorption capacity value of Bacillus sphaericus biomass for Ni(II) ions was calculated at 55.55 mg/g using the Langmuir isotherm model. The thermodynamic study shows the Ni(II) biosorption was spontaneous and exothermic in nature. The change in heat of sorption (ΔH°) and the isosteric heat of sorption (ΔHr) values indicate the physical sorption as the predominant mechanism for Ni(II) biosorption. The Ni(II) ions were recovered effectively from Bacillus sphaericus biomass using 0.1 M HNO3 and can be recycled. FTIR results showed that carboxylic and amine groups of Bacillus sphaericus cells were responsible for Ni(II) binding.
... Some biosorbents such as Acacia leucocephala (Subbaiah et al., 2009), Azadirachta indica (Bhattacharyya et al., 2009), Bacillus pumilus (Wierzba and Latala, 2010), Exiguobacterium sp. (Amer et al., 2014), Elaeagnus Angustifolia (Amiri et al., 2014), Mucor hiemalis (Shroff and Vaidya, 2011), Pseudomonas fluorescens (Wierzba and Latala, 2010), Pseudomonas sp. (Gialamouidis et al., 2009), Rhodococcus opacus (Cayllahua et al., 2009), Salvadora persica L. branches (Ileri et al., 2014), Staphylococcus xylosus (Gialamouidis et al., 2009), Streptomyces rimosus (Selatnia et al., 2004), and ...
Surfactant-enhanced solubilization and subsequent biodegradation of phenanthrene and pyrene from aqueous solutions by Arthrobacter strain Sphe3 was investigated. The results show that growth of Arthrobacter strain Sphe3 was increased upon increase in concentration of Tween 20 and Tween 80. Inhibition of bacterial growth was observed with increasing Triton X-100 concentrations, whereas sodium dodecyl sulfate (SDS) totally inhibited this bacterial growth. Phenanthrene and pyrene solubilization was enhanced in the presence of surfactants and found to be linearly proportional to their concentrations, above the critical micelle concentration (CMC). In addition, Tween 20 and Tween 80 enhanced the biodegradation of phenanthrene and pyrene. The high correlation coefficient (R
2) values obtained at all the concentrations studied, suggest that biodegradation kinetics of both phenanthrene and pyrene in the presence of Tween 20 and Tween 80 follow first-order kinetic equation model. Experimental results suggest that Tween 20 and Tween 80 may have great potential for applications in bioremediation of these polycyclic aromatic hydrocarbon (PAH) compounds using Arthrobacter strain Sphe3.
