Removal of arsenic and iron from mine-tailing leachate using chitosan hydrogels synthesized by gamma radiation
Por:
Carlos Burillo, Juan, Castro-Larragoitia, Javier, Burillo, Guillermina, Ortega, Alejandra, Medellin-Castillo, Nahum
Publicada:
1 jul 2017
Resumen:
Mine residue and leachate were sampled from an acid mine drainage site
near Arroyo San Pedro, which is one of the oldest abandoned mine
districts in San Luis Potosi, Mexico, and characterized by X-ray
diffraction and inductively coupled plasma-optical emission
spectroscopy, confirming the presence of Fe, As, and SO42-. To address
this problem, chitosan network (net-CS) and chitosan
network-N-vinylcaprolactam/N-N-dimethylacrylamide (net-CS)-g-NVCL/DMAAm
hydrogels were synthesized and used as adsorbents of the different ions
present in the aforementioned leachate by batch equilibrium procedure.
Kinetics, isotherms, and ions dissolved in leachate were evaluated. The
gels showed the highest adsorption capacity for As and Fe ions. The
adsorption capacity of the net-CS hydrogels for As (V) and Fe(III) was
0.786 and 76.85 mg/g, respectively, attained after 50 h. The surface of
the hydrogels was investigated by scanning electron microscopy and
Fourier transform infrared spectroscopy, before and after the adsorption
process, where the presence of a bond between the hydrogels and heavy
metals ions, which is commonly observed in organic groups, was observed.
In addition, Freundlich and Langmuir adsorption isotherms constants were
determined for the As and Fe ions, and it was found that the Freundlich
isotherm, with a first-order pseudo model, better fitted the adsorption
process, indicating heterogeneous sorption, and the retention process
occurred by chemisorption. The results from the Geochemists Workbench
(GWB) software program revealed that arsenates, such as H3AsO4, H2AsO4-,
as well as Fe++, FeSO4(aq) and FeOH+ were the common aqueous species
found in the leachate at pH = 2.9.
Filiaciones:
Carlos Burillo, Juan:
Univ Autonoma San Luis Potosi, Fac Ingn, Av Dr Manuel Nava 8, San Luis Potosi 78290, Slp, Mexico
Castro-Larragoitia, Javier:
Univ Autonoma San Luis Potosi, Fac Ingn, Av Dr Manuel Nava 8, San Luis Potosi 78290, Slp, Mexico
Burillo, Guillermina:
Univ Nacl Autonoma Mexico, Inst Ciencias Nucl, Ciudad Univ,Ave Univ 3400 Del Coyoacan, Mexico City 04510, DF, Mexico
Ortega, Alejandra:
Univ Nacl Autonoma Mexico, Inst Ciencias Nucl, Ciudad Univ,Ave Univ 3400 Del Coyoacan, Mexico City 04510, DF, Mexico
Medellin-Castillo, Nahum:
Univ Autonoma San Luis Potosi, Fac Ingn, Ctr Invest & Estudios Posgrad, Av Salvador Nava 8, San Luis Potosi 78290, Slp, Mexico
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