Abstract:
Heavy metal removal from wastewater remains a paramount challenge with rapid
industrialization and its ubiquitous utilities. Currently, the generation of clean water
and environmental protection are two indispensable/requisite areas for a sustainable
society. Two-dimensional (2D) materials' applicability in water treatment is
continuously accelerating by enabling new discoveries. Recently, MXenes generated
tremendous popularity in the 2D materials family due to unique physicochemical
properties and stability that as adsorbents make them attractive for the removal of
heavy metals. Although the adsorption performance of MXenes may compete
effectively with other nanomaterials adsorbents, the interplay with different materials
is insufficient/inadequate/restricted for further development of low-cost material for
commercial applications. Herein, a potential MXene (Ti3AlC2) combined with
Chitosan, an abundant crustacean’s polymer, as surfactant on polyurethane foam (PUF)
for the removal of toxic hexavalent chromium from synthetic wastewater via
adsorption process. The sorption capabilities of PUF for wastewater were enhanced
using MXene nano-sheets adherence to the pores, while Chitosan beforehand was used
as a surfactant for constructive deposition of MXene nano-sheets. Positively charged
Chromium (VI) ions are adsorbed on negatively charged MXene via electrostatic
attraction and ion exchange mechanism. An assay of assessment is done through a
series of batch and fixed-bed column studies using PUF cubes coated with Chitosan
and three different layers of MXene over Chitosan. Complete removal of hexavalent
chromium in 2 hours has been observed in the batch process, which is quite promising.
Detailed characterization techniques were employed to identify elements, structural
type, and chemical functionality. Additionally, Langmuir and Freundlich kinetic model
for batch operation confirms the chemisorption during the process. Furthermore,
briefed fixed bed column experiments were performed to check the continuous
operation stability of the adsorbent for future perspective. The experimental study
attributed the favorable and economically sustainable aspect of potential adsorbent in
water treatment applications as compared to the usage in an individual capacity in
powder form.
