Enhanced removal of chromium (VI) from wastewater
using active carbon derived from Lantana camara plant
as adsorbent
Sujitha Ravulapalli and Ravindhranath Kunta
ABSTRACT
Activate carbon prepared from the stems of Lantana camara plant (ACSLC) is investigated as
adsorbent for the removal of chromium (Cr) (VI) from polluted water using batch methods of
extraction. Various extraction conditions such as pH, initial concentration of Cr (VI), sorbent dosage,
temperature, equilibration time and presence of co-ions are optimized. The adsorption capacity is
found to be 26.25 mg/g and is more than hitherto reported sorbents in the literature. The spent
adsorbent can be regenerated and reused with a marginal reduction in its adsorption capacity. The
active carbon is characterized by field emission scanning electron microscope (FESEM), X-ray
diffraction (XRD) and Fourier-transform infrared (FT-IR) studies. The sorption mechanism is
investigated using various isotherm models and found that the Freundlich model describes the
adsorption process well. Thermodynamic studies reveal the endothermic and spontaneous nature of
physisorption. The kinetics of adsorption is well defined by the pseudo-second-order model. The
methodology developed is successfully applied to effluent samples collected at various industries.
Sujitha Ravulapalli
Ravindhranath Kunta (corresponding author)
Department of Chemistry,
Koneru Lakshmaiah Education Foundation,
Green Fields, Vaddeswaram-522 502, Guntur Dt.,
A.P.,
India
E-mail: ravindhranath.kunta@gmail.com
Key words | active carbon, adsorbent, adsorption, chromium (VI), Lantana camara plant, polluted
water
INTRODUCTION
Chromium is a potential pollutant and it exists in waters
either in trivalent or hexavalent states. Of these two oxi-
dation states, hexavalent chromium is more toxic (Sharma
& Forster ; Selvi et al. ). The main source of chro-
mium contamination is untreated or ill-treated effluents
from chromium based industries such as mining, painting,
car manufacturing, textile, electroplating and tannery indus-
tries, etc. (Wang et al. ; Vasudevan et al. ; Dias et al.
; Schneider et al. ). If the untreated effluents are
discharged into the environment, the water bodies are
contaminated with the accumulated amounts of Cr (VI)
and the consumption of such contaminated water causes
serious health problems such as nausea, skin ulcers, mal-
functioning of liver, kidneys and lung cancer (Richard &
Bourg ; Kotas ´ & Stasicka ). As per WHO, the maxi-
mum allowed limit of Cr (VI) in water is 0.05 mg/L (WHO
; Indian Standard Drinking Water Specifications ).
The commonly adopted techniques to remove Cr (VI)
ions from industrial effluents are precipitation (Zhang
et al. ; Parameswari et al. ), ion exchange (Rengaraj
et al. ; Cavaco et al. ), nanofiltration (Ahmed et al.
), electrodeposition (Chaudhary et al. ) and floccu-
lation (Metcalf & Eddy ). Recently, increasing interest is
seen in developing adsorbents based on materials derived
from plants in controlling the potential pollutants. In fact,
our research group is investigating these bio-methods and
developed methodologies for the removal of Cr (VI) (Sree
Devi & Ravindhranath ), Al (III) (Aruna Kumari &
Ravindhranath ), Zn (Papodu et al. ), F
(Suneetha
et al. ; Sujitha & Ravindhranath a), nitrite (Suneetha
& Ravindhranath ), phosphate (Sujitha & Ravindhra-
nath b), ammonia (Prameela Rani & Ravindhranath
), lead (Sujitha & Ravindhranath ) and dyes (Sujitha
& Ravindhranath a, b).
The literature survey reveals that there are reports using
non-conventional adsorbents such as modified lettuce leaves
(Li et al. ), cashew nut shell powder (Coelho et al. ),
active carbon of waste rubber tires (Gupta et al. ) and
H
3
PO
4
activated peanut shell powder (ALOthman et al.
) and Fox nutshell carbon (Kumar & Jena ).
1377 © IWA Publishing 2018 Water Science & Technology | 78.6 | 2018
doi: 10.2166/wst.2018.413
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