Distinctive green recovery of silver species from modified cellulose: mechanism and spectroscopic studies.
The present study aimed to recover precious silver in order to identify the adsorption coupled reduction pathways that determine this process. A combination technique of adsorption and nanocrystallization was used to investigate the recovery of silver species from taurine-cellulose (T-DAC) samples. The non-synthetic route of nanocrystallization yielded spherical zero-valent silver sized ∼ 18 nm. Rate-controlling steps were modeled by adsorption parameters by the best fit of Langmuir capacity (55 mg/g), pseudo-second order curves, and exothermic chemical reactions. The T-DAC was an excellent sorbing phase for the treatment of silver-polluted waters over a broad range of pH (2.1-10.1) and varying ionic strengths (8.5-850 mM, as NaCl), which are the conditions often encountered in industrial and mining effluents. A good recovery of silver (40-65%) was also obtained in the presence of Cd(II), Co(II), Cr(VI), Ni(II), and As(V) at lower or equivalent concentrations with Ag(I), either from individually added metals or from all metal ions mixed together. Desorption was compared with a series of five eluents including complexing agents. In these experiments acidified thiourea yielded 86% desorption of Ag(I). Aqueous silver reduced to metallic silver on the surface of the T-DAC samples, which was confirmed by X-ray photo electron spectroscopy.
Lappeenranta University of Technology, LUT Green Tech, Laboratory of Green Chemistry, Sammonkatu 12, 50130 Mikkeli, Finland. Electronic address: amarendradhar@gmail.com.
Amarendra Dhar
AD
Dwivedi
Lappeenranta University of Technology, LUT Green Tech, Laboratory of Green Chemistry, Sammonkatu 12, 50130 Mikkeli, Finland; School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), 100 Banyeon-ri, Eonyang-eup, Ulju-gun, Ulsan 698-805, Republic of Korea.
Shashi Prabha
SP
Dubey
Lappeenranta University of Technology, LUT Green Tech, Laboratory of Green Chemistry, Sammonkatu 12, 50130 Mikkeli, Finland.
Mika
M
Sillanpää
Fibre and Particle Engineering Laboratory, University of Oulu, P.O. Box 4300, FI-90014, Finland.
Henrikki
H
Liimatainen
Fibre and Particle Engineering Laboratory, University of Oulu, P.O. Box 4300, FI-90014, Finland.
Terhi
T
Suopajärvi
Fibre and Particle Engineering Laboratory, University of Oulu, P.O. Box 4300, FI-90014, Finland.
Jouko
J
Niinimäki
School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), 100 Banyeon-ri, Eonyang-eup, Ulju-gun, Ulsan 698-805, Republic of Korea.
Young-Nam
YN
Kwon
School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), 100 Banyeon-ri, Eonyang-eup, Ulju-gun, Ulsan 698-805, Republic of Korea.
Changha
C
Lee
D000327:Adsorption; D002482:Cellulose / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D019216:Metals, Heavy / Q000737:chemistry; D009994:Osmolar Concentration; D012834:Silver / Q000737:chemistry*; D018030:Silver Compounds / Q000737:chemistry*; D013816:Thermodynamics
D019216:Metals, Heavy; D018030:Silver Compounds; D012834:Silver; D002482:Cellulose
Desorption; Nanocrystallization; Taurine-cellulose