Biosorption of nickel onto treated alga (Oedogonium hatei): Application of isotherm and kinetic models

Pectin-cerium (IV) tungstate composite (Pc/ CT) has been prepared by sol gel method at room temperature. The composite ion exchanger has been characterized using X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and Fourier infrared spectroscopy. The ion exchange capacity, pH titrations, thermal stability and distribution coefficient of composite ion exchanger were investigated. The Na ? ions exchange capacity of the Pc/CT has been observed higher (1.4 meq g -1 ) as compared to its inorganic counterpart (0.8 meq g -1 ). Pc/CT composite ion exchanger was thermally stable and retained about 60 % of its ion exchange capacity up to 400°C. The distribution study has inferred more selective the Pc/CT for Zn 2? as compared to other metal ions. The adsorption efficiency of Pc/CT was tested for methylene blue removal dye from aqueous phase. The removal of dye followed pseudo-second-order kinetics.

Section: Adsorption Kineticssupporting

confidence: 72%

Pectin–cerium (IV) tungstate nanocomposite and its adsorptional activity for removal of methylene blue dye

Gupta

Pathania

Singh

2013

“…Among them, we can include heavy metals, dyes, pesticides, rubber chemicals and diverse industrial wastes and different approaches have been devised in order to reduce them. These strategies include, for example, adsorption to remove heavy metals or dyes (Jain et al 2003;Gupta et al 2006Gupta et al , 2007aGupta et al , 2009Gupta et al , 2010Gupta et al , 2011Mittal et al 2008), photochemical degradation (Gupta et al 2007b), biosorption (Mittal et al 2010) and advanced oxidation process (AOP) (Karthikeyan et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Isolation and characterization of an aerobic bacterial consortium able to degrade roxarsone

Guzmán‐Fierro

Moraga

León

et al. 2014

Roxarsone is an organoarsenical compound used as food additive in the poultry industry. Roxarsone has the potential risk to contaminate the environment, mainly by the use of poultry industry manure as fertilizer, releasing inorganic arsenic to the soil and water. The aim of this work was to isolate and characterize a bacterial consortium capable to degrade roxarsone under aerobic conditions. A bacterial consortium was cultured from a soil sample obtained from a field fertilized with poultry litter containing roxarsone. The consortium was cultured in the presence or absence of roxarsone. Roxarsone degradation and growth kinetics were determined by incubation of the bacterial consortium in the presence of roxarsone at room temperature and under aerobiosis. Both consortiums were characterized molecularly by denaturing gradient gel electrophoresis analysis and metabolically using Biolog Ecoplates. Inorganic arsenic was assessed by precipitation with silver nitrate. The consortium was also analyzed by scanning electron microscopy. The results showed that growth rate of the bacterial consortium was 1.4-fold higher in presence of roxarsone and 81.04 % of the roxarsone was transformed after 7 days of incubation. Molecular characterization revealed the presence of different bacterial groups, being alphaproteobacteria and firmicutes the groups that showed the highest count in both consortiums. The metabolic profile of the consortium did not change in the presence of roxarsone, but it showed a greater ability to oxidize amines, suggesting production of functional amines to decrease the stability of the aromatic ring resonance energy, the principal problem associated with aromatic compounds degradation.

“…Empirical models based on partition coefficients (K d ) or semiempirical Langmuir or Freundlich isotherms are often used to describe adsorbate partitioning between solutions and solid phases (Datta and Bhadoria 1999;Elrashidi and O'Connor 1982;Gupta et al 2007Gupta et al , 2010Mittal et al 2010;Ranjbar and Jalali 2012). However, because partition coefficients depend on solution and solid composition, they cannot be utilized beyond the conditions for which they are measured.…”

Section: Introductionmentioning

confidence: 99%

Surface complexation model of boron adsorption by calcareous soils

Ranjbar

Jalali

2014

This study aimed to evaluate boron (B) adsorption and the capacity of a surface complexation model for simulating this process in calcareous soils. Ten surface soils were collected from different land use areas in Hamedan, Western Iran, to characterize B sorption by soils. The mean B adsorbed by the sample soils varied from 8.9 to 32.8 %. Two empirical models including linear and Freundlich equations fitted well to the experimental data. The linear distribution (K d ) values varied from 1.32 to 6.86 L kg -1 , while the parameters of Freundlich equation including n and K Fr ranged from 1.16 to 1.33 and 3.31-16.81, respectively. The comparison of two empirical models indicated that B adsorption followed a nonlinear pattern. The soil organic matter had positive correlations with Freundlich and linear distribution coefficients. However, empirical models were not suitable for explaining the mechanism of B adsorption, so a surface complexation model was used to simulate and predict the B adsorption process. B adsorption modeling was conducted using Visual MINTEQ and PHREEQC, based on the assemblage of major surface components (hydrous ferric oxides, aluminum hydroxides, calcium carbonate, and humic acids). B adsorption was successfully modeled by surface complexation. The significant contribution of organic matter to B complexes was resulted from both experimental data and mechanistic modeling.