
Proceedings of CUChE Alumni Symposium 2022
On “Circular Economy on Sustainable Basis: The Role of Chemical Engineers”
CUChEAA ISBN: 978-81-954649-1-3
December 2022
P a g e | 2 Volume 2, Issue 1
2017), etc. (Article, 2009; Cheng et al., 2021; Dubey et
al., 2019; Maheshwari and Agrawal, 2020; Rajamani,
2019; Rioyo et al., 2018; Selvaraj et al., 2020;
Subramani and Jacangelo, 2014). With the similar view,
in our previous investigation dye contaminated (Congo
red dye) wastewater with initial concentration of 10 ppm
was treated with synthesized adsorbent proposing a great
potential in terms of energy statistics (3.4 kWh) and
efficacy (97.7 %) (Maheshwari et al., 2020).
Furthermore, electrocoagulation was examined for acid
green 20 and reactive yellow 17 treatment proposing
strong efficacies with 92.1 and 86.5 % in a binary
system reporting a current density of 100 mA/cm
2
.
Therefore, it can be suggested that electrochemical
treatment could be significant solution for treatment for
binary system (Moneer et al., 2021). Moreover, there
were membrane techniques adopted for salt removal and
dye irradiation. For instance, Lai et al. (2016) fabricated
graphene oxide-based thin-film NF membrane. They
investigated the attenuation of salts, reporting 95 %, 91
%, and 62 % rejections for sodium sulphate, magnesium
sulphate, and magnesium chloride, respectively (Lai et
al., 2016). A recent study by Sun et al. (2019) supported
the fact by investigating the NF 90 and NF 270
membranes for inorganic salt removal. The research
revealed that significantly massive ion rejections were
reached in the case of NF 90 with 99 %, 98 %, 96 %,
and 84 % for SO
4
2-
, F
-
, Cl
-
, and NO
3-
, respectively (Sun
et al., 2019). However, these instances suggest that
technologies possess strong outputs in terms of removal
but are inefficient considering aspects like energy
consumption. Henceforth, an energy-efficient system is
needed for removal of water contaminating elements like
dyes, and salts as they are heavily discharged in the
natural water bodies. Apart from the stated conventional
techniques, capacitive deionization (CDI) has been
explored as a new and advancement to the areas of water
remediation and wastewater treatment.
There are versatile applications of the CDI process for
water treatment with the advantage of being
environmentally friendly, cost-efficient, lower energy
statistics, easy to handle design, facile electrode
regeneration, and limited voltage implementation (Xing
et al., 2020). The approach has the essential operation of
sorbing ions from the simulated stream using a
connected system of electrodes applying a DC power
(Ding et al., 2019). The practical reason for removing
ions is forming an electrical double layer (EDLC) due to
electrostatic force of attractions between electrodes
surface and existing ions in the stream. Various flow
architectures are used, namely, flow-by, flow-through,
inverted CDI, hybrid CDI, membrane CDI, intercalation
CDI, and the research is still ongoing (Maheshwari and
Agrawal, 2020). The most prominent property to be
considered for CDI is the electrode’s material, which
implies double layer formation over the surface of the
electrode, enhancing desalination properties. Therefore,
the selection of active material is its fundamental
parameter to record performance and carbon, and its
extended families are well-known materials for specific
surface area and morphology (Xie et al., 2018a). So
activated carbon is the most widely reported material for
the fabrication of electrodes (Moneer et al., 2021). Not
only the accessibility for ion sorption but the activated
carbon is said to have potentially electrochemical solid
properties (Xie et al., 2018b).
Activated carbon is the widely used material for
removing dyes, pharmaceuticals, heavy metals, etc., due
to huge surface accessibility (Xie et al., 2018b).
Therefore, CDI would be suitable for removing ionic
species like salts ions. There were many investigations
performed in the literature using activated carbon. For
instance, Kyaw et al. (2021) used dry date palm leaflets
to synthesize activated carbon modified with sodium
hydroxide implemented for fabrication of electrode
treating 100 mg/L NaCl solution implementing 1.2 V
reporting 5.38 mg/g sorption capacity (Kyaw et al.,
2021). Moreover, another researcher also used peanut
shells after impregnation with phosphoric acid for
electrode's synthesis, revealing a sorption performance
of 65 mg/g for 1000 mg/L TDS of the inlet, providing
120 min of electrosorption duration (Wu et al., 2019).
Similarly, another investigation was reported on the
feasibility of pine pollen-derived biomass to develop
activated carbon used for fabricating electrodes. The
investigation reported 7.25 mg/g capacity for 50 µs/cm
inlet concentration of NaCl solution at the operating
voltage of 2.0 V (Liu et al., 2019). A similar pattern was
observed by a study synthesizing activated carbon from
sugar cane bagasse and chemically activating with zinc
chloride reporting a significant increase in capacitance
from 12 to 86 F/g. The sorption capacity increased from
48 – 74 % operating at 1.2 V for the initial concentration
of 600 mg/L (Lado et al., 2017). Therefore, the surface
impregnations and interface modifications are in trend
due to drastic enhancements in material properties like
surface area, porosity, etc. (Rambabu et al., 2020). These
reduce the system's cost and lead to the sustainable
pathway of utilizing agro-based waste discharged
directly into the environment. Therefore, there is a dire
need to implement such materials for electrode
fabrication as it's a green process. The modality for pore
distribution supports the fact that the synthesized
activated carbon can range from 2 mm to 100 mm, i.e.
microporous ( lesser than or equal to 2 mm), mesoporous
( greater than 2 to less than 50 mm ), and macro-porous
(50 mm and greater) divisions (Rambabu et al., 2020).
Moreover, when the base material is synthesized when
clubbed with impregnations coatings, doping can
drastically enhance the desalting performance of the
electrode. They have disordered arrangements with
surface areas ranging from 300 to 5000 m
2
/g.
Henceforth in the present article, the versatility of CDI
has been explored for RO reject (R-RO) and Congo red
dye (D-CR) treatment via developed biochar based
activated carbon electrode. The study involves
characterization of developed material which checks its
suitability for sorption of ions over surface including
Brunauer–Emmett–Teller (BET) for evaluating specific
surface area, Scanning electron microscope (SEM) for