Abstract:
This study reports the preparation of nanobiochar (NBC) via top-down approach of bioenergy waste-derived
dendro biochar through mechanised grinding in order to assess its capacity to remove emerging contaminants,
such as antibiotics, agrochemicals, and potentially toxic elements from aqueous media. Preconditioned biochar
was disc milled in ethanol media, and the resulting colloidal biochar was dispersed in water to obtain the NBC
fraction by centrifugation. Adsorption edge and isothermexperimentswere carried out at pH3 to 8 and NBC dosages
of 0.5 g/L for oxytetracycline (OTC), glyphosate (GL), hexavalent chromium(CrVI), and cadmium(CdII).NBC
was characterised by scanning electron microscopy, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller
surface area, and Fourier transforminfrared spectroscopy, which demonstrated the flakey and graphitic nature of
the NBC particles with a surface area of 28 m2/g and the presence of different functional groups, such as\\OH,
C_O,\\NH, and CH3. The best pH for OTC and Cd(II) was 9, whereas the best pH levels for GL and Cr(VI) were
7 and 4, respectively. Isotherms depicted a positive cooperative adsorption mechanism by providing the best
fit to the Hills equation,with high removal capacities for four contaminants. Dendro NBC showed the best performance,
demonstrated by the high partition coefficient for the removal of OTC, GL, Cr(VI), and Cd(II) over various
types of adsorbents. The overall results indicated that graphitic NBC produced by mechanical grinding of dendro
biochar is a promising material for the removal of OTC, GL, Cr(VI), and Cd(II) from aqueous media.
