Zeeshan Ajmal - Academia.edu (original) (raw)

Papers by Zeeshan Ajmal

Science Direct, 2022

Worldwide, arsenic contamination has become a matter of extreme importance owing to its potential... more Worldwide, arsenic contamination has become a matter of extreme importance owing to
its potential toxic, carcinogenic and mutagenic impact on human health and the environment. The
magnetite-loaded biochar has received increasing attention for the removal of arsenic (As) in contaminated
water and soil. The present study reports a facile synthesis, characterization and adsorption
characteristics of a novel magnetite impregnated nitrogen-doped hybrid biochar (N/
Fe3O4@BC) for efficient arsenate, As(V) and arsenite, As(III) removal from aqueous environment.
The as-synthesized material (N/Fe3O4@BC) characterization via XRD, BET, FTIR, SEM/EDS
clearly revealed magnetite (Fe3O4) impregnation onto biochar matrix. Furthermore, the adsorbent
(N/Fe3O4@BC) selectivity results showed that such a combination plays an important role in targeted
molecule removal from aqueous environments and compensates for the reduced surface area.
The maximum monolayer adsorption (Qmax) of developed adsorbent (N/Fe3O4@BC) (18.15 mg/g
and 9.87 mg/g) was significantly higher than that of pristine biochar (BC) (9.89 & 8.12 mg/g) and
magnetite nano-particles (MNPs) [7.38 & 8.56 mg/g] for both As(III) and As(V), respectively. Isotherm
and kinetic data were well fitted by Langmuir (R2= 0.993) and Pseudo first order model
(R2= 0.992) thereby indicating physico-chemical sorption as a rate-limiting step. The co-anions
(PO4
3-) effect was more significant for both As(III) and As (V) removal owing to similar outer electronic
structure. Mechanistic insights (pH and FTIR spectra) further demonstrated the remarkable
contribution of surface groups (OH–, –NH2 and –COOH), electrostatic attraction (via H- bonds),
surface complexation and ion exchange followed by external mass transfer diffusion and As(III)
oxidation into As(V) by (N/Fe3O4@BC) reactive oxygen species. Moreover, successful desorption
was achieved at varying rates up to 7th regeneration cycle thereby showing (N/Fe3O4@BC) potential
practical application. Thus, this work provides a novel insight for the fabrication of novel magnetic
biochar for As removal from contaminated water in natural, engineering and environmental
settings.

Science Direct, 2022

Worldwide, arsenic contamination has become a matter of extreme importance owing to its potential... more Worldwide, arsenic contamination has become a matter of extreme importance owing to
its potential toxic, carcinogenic and mutagenic impact on human health and the environment. The
magnetite-loaded biochar has received increasing attention for the removal of arsenic (As) in contaminated
water and soil. The present study reports a facile synthesis, characterization and adsorption
characteristics of a novel magnetite impregnated nitrogen-doped hybrid biochar (N/
Fe3O4@BC) for efficient arsenate, As(V) and arsenite, As(III) removal from aqueous environment.
The as-synthesized material (N/Fe3O4@BC) characterization via XRD, BET, FTIR, SEM/EDS
clearly revealed magnetite (Fe3O4) impregnation onto biochar matrix. Furthermore, the adsorbent
(N/Fe3O4@BC) selectivity results showed that such a combination plays an important role in targeted
molecule removal from aqueous environments and compensates for the reduced surface area.
The maximum monolayer adsorption (Qmax) of developed adsorbent (N/Fe3O4@BC) (18.15 mg/g
and 9.87 mg/g) was significantly higher than that of pristine biochar (BC) (9.89 & 8.12 mg/g) and
magnetite nano-particles (MNPs) [7.38 & 8.56 mg/g] for both As(III) and As(V), respectively. Isotherm
and kinetic data were well fitted by Langmuir (R2= 0.993) and Pseudo first order model
(R2= 0.992) thereby indicating physico-chemical sorption as a rate-limiting step. The co-anions
(PO4
3-) effect was more significant for both As(III) and As (V) removal owing to similar outer electronic
structure. Mechanistic insights (pH and FTIR spectra) further demonstrated the remarkable
contribution of surface groups (OH–, –NH2 and –COOH), electrostatic attraction (via H- bonds),
surface complexation and ion exchange followed by external mass transfer diffusion and As(III)
oxidation into As(V) by (N/Fe3O4@BC) reactive oxygen species. Moreover, successful desorption
was achieved at varying rates up to 7th regeneration cycle thereby showing (N/Fe3O4@BC) potential
practical application. Thus, this work provides a novel insight for the fabrication of novel magnetic
biochar for As removal from contaminated water in natural, engineering and environmental
settings.