Abstract:
In water treatment, sand unit processes are frequently used to remove turbidity. In order to enhanced
the performance of the sand, a surface modification was done using graphite oxide. The core-shell
granules were fabricated using graphite oxide coated river sand. Graphite oxide was derived from
high purity vein graphite in Sri Lanka. Repeated coating of graphite oxide on the sand followed by low
temperature (110 °C) thermal pyrolysis yield hierarchical core-shell structure where several layers
of graphite oxide covered the sand particulates. Mineralogical and physicochemical characterization
of the novel adsorbent was carried out by Energy Dispersive X-Ray attached to Scanning Electron
Microscopy (SEM-EDX), Fourier-Transform Infrared Spectrometry (FTIR), and X-ray Powder
Diffraction (XRD). The operational parameters such as contact time, initial calcium ion concentration,
adsorbent dose and initial pH of the solution were evaluated in batch procedures at room temperature
(26±2 °C) using Five time GO/sand combination which observed as the most effective combination
for calcium ion removal from hard water. Characterization studies reveal that uneven coatings of
graphene oxide present on the surface of Nanocomposite is containing oxygen-based functional
groups (C-O, C=O, O-H) in addition to C-C groups. Optimization studies showed that, the most
effective dosage of the adsorbent is 5.0 g with initial calcium ion concentration 50 mg/L. It appears
that there was no significant effect on the calcium ion removal over a wide range of pH 4-10 and
the process began to reach equilibrium after 20 minutes. Finally, super sand granules show high
partiality towards calcium ions and it will be important for the treatment of the hard water and the
multiple coated GO/sand combination can be used to regulate excess water calcium and turbidity
simultaneously.
