Impact of secondary salts, temperature, and pH on the colloidal stability of graphene oxide in water
Por:
Mancillas-Salas, Sergio, Reynosa-Martinez, Ana C., Barroso-Flores, J., Lopez-Honorato, Eddie
Publicada:
31 may 2022
Resumen:
The stability of graphene oxide (GO) in water is extremely relevant
because of its application as an adsorbent material, as well as for its
fate and behavior in the environment. Zeta potential was used to study
the effect of secondary salts (carbonate, sulfate, and phosphate),
temperature (20 to 60 degrees C), and pH (5 to 9) on the stability of
six different GOs produced from natural, synthetic, and amorphous
graphite-with and without the use of attrition milling. Generally, GOs
produced with attrition-milled graphites had lower zeta-potentials than
their unmilled counterparts because of their smaller particle sizes and
higher concentration of oxygen-containing functional groups. It was
observed that GO produced from graphite and synthetic graphite had
zeta-potential values lower than -30 mV, even at 30 degrees C. However,
it was observed that all the GOs studied were unstable in the presence
of carbonate and sulfate salts at concentrations between 170 and 1695 mg
L-1, as they reached a zeta-potential of -4.1 mV. Density-functional
theory electronic structure calculations suggested that the instability
of GO in the presence of carbonate and sulfate was caused by the
abstraction of a proton resulting in interaction energies E-int of 28.3
and 168.9 kJ mol(-1), respectively. Our results suggest that
temperatures above 30 degrees C, as well as carbonate and sulfate salts
at concentrations relevant to arid and semi-arid regions, could promote
the formation of agglomerates of GO, thus limiting its use and mobility
in water.
Filiaciones:
Mancillas-Salas, Sergio:
IPN, Ctr Invest & Estudios Avanzados, CINVESTAV, Unidad Saltillo, AV Ind Met 1062, Ramos Arizpe 25900, Mexico
Reynosa-Martinez, Ana C.:
IPN, Ctr Invest & Estudios Avanzados, CINVESTAV, Unidad Saltillo, AV Ind Met 1062, Ramos Arizpe 25900, Mexico
Barroso-Flores, J.:
Univ Nacl Autonoma Mexico, Inst Quim, Ciudad Univ, Mexico City 04510, DF, Mexico
Ctr Conjunto Invest Quim Sustentable UAEM UNAM, Unidad San Cayetano, Carretera Toluca Atlacomulco Km 14-5, Toluca 50200, Estado De Mexic, Mexico
Lopez-Honorato, Eddie:
IPN, Ctr Invest & Estudios Avanzados, CINVESTAV, Unidad Saltillo, AV Ind Met 1062, Ramos Arizpe 25900, Mexico
Oak Ridge Natl Lab, POB 2009, Oak Ridge, TN 37831 USA
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