Use of Algae for Removing Heavy Metal Ions From Wastewater: Progress and Prospects

Mehta, Surya Kant; Gaur, J. P.

doi:10.1080/07388550500248571

Cited by 712 publications

(465 citation statements)

References 216 publications

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“…Several groups have demonstrated that photosynthetic bacteria are also able to metabolize metals and metalloids and became additional possible candidates in bioprotection and bioremediation of the environment (Mehta and Gaur 2005;Singh et al 2009;Glick 2010). Trace metals essential (manganese, iron, cobalt, copper, zinc, etc.…”

Section: Introductionmentioning

confidence: 99%

Stoichiometry and kinetics of mercury uptake by photosynthetic bacteria

2017

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Mercury adsorption on the cell surface and intracellular uptake by bacteria represent the key first step in the production and accumulation of highly toxic mercury in living organisms. In this work, the biophysical characteristics of the mercury bioaccumulation are studied in intact cells of photosynthetic bacteria by use of analytical (dithizone) assay and physiological photosynthetic markers (pigment content, fluorescence induction and membrane potential) to determine the amount of mercury ions bound to the cell surface and taken up by the cell. It is shown that the Hg(II) uptake mechanism 1) has two kinetically distinguishable components, 2) includes co-opted influx through heavy metal transporters since the slow component is inhibited by Ca 2+ channel blockers, 3) shows complex pH-dependence demonstrating the competition of ligand binding of Hg(II) ions with H + ions (low pH) and high tendency of complex formation of Hg(II) with hydroxyl ions (high pH) and 4) is not a passive but an energy-dependent process as evidenced by light-activation and inhibition by protonophore. Photosynthetic bacteria can accumulate Hg(II) in amounts much (about 10 5 ) greater than their own masses by well defined strong and weak binding sites with equilibrium binding constants in the range of 1 (μM) -1 and 1 (mM) -1 , respectively. The strong binding sites are attributed to sulfhydryl groups as the uptake is blocked by use of sulfhydryl modifying agents and their number is much (two orders of magnitude) smaller than the number of weak binding sites. Biofilms developed by some bacteria (e.g. Rvx. gelatinosus) increase the mercury binding capacity further by a factor of about five. Photosynthetic bacteria in the light act as sponge of Hg(II) and can be potentially used for biomonitoring and bioremediation of mercury contaminated aqueous cultures.2

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Section: Introductionmentioning

confidence: 99%

Stoichiometry and kinetics of mercury uptake by photosynthetic bacteria

2017

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“…Biosorption has been considered as a promising technology for the removal of low-level toxic metals from industrial effluents and natural waters (Volesky, 2007;Mehta and Gaur, 2005;Wang and Chen, 2009). Marine algae have received greater attention because of their high metal biosorption capacity, low cost, and renewable nature.…”

Section: Introductionmentioning

confidence: 99%

“…In recent years, various efforts have been focused on the immobilization of alga biomass, which is a potential way to overcome the disadvantages. Such supporting materials as alginate (Bayramoglu and Yakup Arıca, 2009;Mata et al, 2009), silica gel (Rangsayatorn et al, 2004), polyacrylamide and polyurethanes (Mehta and Gaur, 2005) were used for the biomass immobilization. However, metal uptake efficiency of immobilized cells is reportedly often much lower than that of raw biomass.…”

Section: Introductionmentioning

confidence: 99%

Improvement of metal adsorption onto chitosan/Sargassum sp. composite sorbent by an innovative ion-imprint technology

et al. 2011

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Ion-imprinted chitosan Sargassum sp. a b s t r a c tTechnology for immobilization of biomass has attracted a great interest due to the high sorption capacity of biomass for sequestration of toxic metals from industrial effluents.However, the currently practiced immobilization methods normally reduce the metal sorption capacities. In this study, an innovative ion-imprint technology was developed to overcome the drawback. Copper ion was first imprinted onto the functional groups of chitosan that formed a pellet-typed sorbent through the granulation with Sargassum sp.; the imprinted copper ion was chemically detached from the sorbent, leading to the formation of a novel copper ion-imprinted chitosan/Sargassum sp. (CICS) composite adsorbent. The copper sorption on CICS was found to be highly pH-dependent and the maximum uptake capacity was achieved at pH 4.7e5.5. The adsorption isotherm study showed the maximum sorption capacity of CICS of 1.08 mmol/g, much higher than the non-imprinted chitosan/Sargassum sp. sorbent (NICS) (0.49 mmol/g). The used sorbent was reusable after being regenerated through desorption. The FTIR and XPS studies revealed that the greater sorption of heavy metal was attributed to the large number of primary amine groups available on the surfaces of the ion-imprinted chitosan and the abundant carboxyl groups on Sargassum sp.. Finally, an intraparticle surface diffusion controlled model well described the sorption history of the sorbents. ª 2010 Elsevier Ltd. All rights reserved. IntroductionBiosorption has been considered as a promising technology for the removal of low-level toxic metals from industrial effluents and natural waters (Volesky, 2007;Mehta and Gaur, 2005;Wang and Chen, 2009). Marine algae have received greater attention because of their high metal biosorption capacity, low cost, and renewable nature. They can effectively remove heavy metal ions with concentrations ranging from few ppm to several hundreds ppm. The maximum metal biosorption capacity ranging from 0.1 to 1.5 mmol/g biosorbent has been reported (Davis et al., 2003; Yang, 2005, 2006 A v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / w a t r e s w a t e r r e s e a r c h 4 5 ( 2 0 1 1 ) 1 4 5 e1 5 40043-1354/$ e see front matter ª

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“…The samples were allowed to settle overnight at 4°C to separate the zooplankton (Watanabe et al, 1992). Extracellularly bound metals were separated by resuspending a subsample of the phytoplankton in 2 mM EDTA solution for 5 min (Mehta and Gaur, 2005;Hassler et al, 2004;Zeng et al, 2009). The raw and EDTA-washed phytoplankton subsamples were lyophilized and stored for ICP-MS determination.…”

Section: Sample Preparationmentioning

confidence: 99%

“…Among numerous bloomforming cyanobacterial species, the colonial Microcystis is common genus in freshwaters (Visser et al, 2005;Whitton and Potts, 2012). The cell walls of these cyanobacteria have several functional groups -especially carboxyl groups of polysaccharide that provide biosorptive sites for complexation, ionic exchange and precipitation (Mehta and Gaur, 2005;Kumar and Gaur, 2011). The affinity of these compounds for metals and other pollutants potentially provide Microcystis with the capacity to bioaccumulate them.…”

Section: Introductionmentioning

confidence: 99%