Journal of Environmental Treatment Techniques  
2020, Volume 8, Issue 3, Pages: 1144-1150  
J. Environ. Treat. Tech.  
ISSN: 2309-1185  
Journal web link:  
Adsorption Studies on the Removal of Hexavalent  
Chromium (Cr (VI)) from Aqueous Solution using  
Black Gram Husk  
Sunil Rajoriya*, Ahlaam Haquiqi, Bhawna Chauhan, Girish Tyagi*, Avdesh Singh Pundir*,  
Ajay Kumar Jain, Divya Agarwal  
Chemical Engineering Department, Meerut Institute of Engineering and Technology Meerut-250005  
Received: 17/06/2020  
Accepted: 09/07/2020  
Published: 20/09/2020  
In the current work, black gram husk (BGH) as an effective adsorbent was used to remove the hexavalent chromium (Cr (VI)) from  
aqueous solution in the batch mode. The characterization of adsorbent was done by Fourier transform infrared spectroscopy (FT-IR) to  
identify the functional groups present on the surface of BGH. The study was done with synthetic wastewater having a Cr (VI)  
concentration of 100 mg/L. Batch experiments were conducted to study the effects of various process parameters such as solution pH (1  
7), adsorbent dosage (0.5  1.5 g/100 mL), initial Cr (VI) concentration (100  200 mg/L), and contact time (0  30 min) on the  
efficiency of the adsorption process. The maximum % removal of Cr (VI) was 65.23% at the optimized set of process parameters i.e.  
solution pH of 3, adsorbent dosage of 1 g/100 mL, contact time of 15 min. Freundlich and Langmuir adsorption isotherms were applied  
to investigate adsorption data, The observed experimental data fitted well to Langmuir isotherm (R = 0. 9804 and qmax = 9.19 mg/g).  
The reusability study showed that BGH material is recyclable up to only one cycle with 45.19% Cr (VI) removal efficiency. The obtained  
experimental results revealed that BGH as an efficient adsorbent may be used for the Cr (VI) removal from aqueous solutions.  
Keywords: Black gram husk (BGH); Cr (VI); Adsorption; Reusability; Isotherms  
cost, incomplete metal removal, large quantity of toxic sludge,  
high energy requirement (16). However, Adsorption process  
has been found to be suitable process to remove toxic metals  
from wastewater using low cost adsorbents due to its high  
efficiency, simple to operate, low cost, reusability of adsorbent  
In recent years, the polluted water containing heavy metals  
has led to serious issues due to the random discharge of heavy  
metals in to the water bodies (1). Among the heavy metals,  
chromium has the harmful effects on the aquatic environment  
17). In the recent years, many authors have utilized the various  
2). Chromium occurs in two stable oxidation states i.e.  
trivalent chromium (Cr(III)) and hexavalent chromium  
Cr(VI)) in aqueous solution. Cr (VI) compounds are 500 times  
adsorbents towards the removal of chromium from wastewater  
such as modified groundnut hull (2), paper mill sludge (3), tea  
waste (5), neem leaves (18), husk of Bengal gram (19),  
modified corn stalks (20), fertilizer industry waste material  
more toxic as compared to Cr(III) because of its high water  
solubility, carcinogenic, mutagenic properties (3). According  
to the World Health Organization (WHO), the maximum  
acceptable limit of hexavalent chromium concentration is 0.05  
mg/L in wastewater (4). United States Environmental  
Protection Agency (US EPA) has recommended the acceptable  
level of Cr(VI) is 0.05 mg/L for potable water and is 0.1 mg/L  
for inland surface waters (5). If hexavalent chromium is present  
in water beyond the acceptable limit which causes skin  
irritation resulting in ulcer formation, liver damage and  
pulmonary congestion (6). Hence, it is necessary for industries  
to decrease the Cr(VI) concentration from their wastewaters to  
acceptable limit before discharging it into the aquatic  
environment. There have been various processes implemented  
to remove the chromium from industrial wastewater including  
ion exchange (7,8), electro-dialysis (9), chemical coagulation  
21), distillery sludge (22), coconut husk and palm pressed  
fibers (23).  
To the best of our knowledge, none study has been reported  
in literature on the utilization of the husk of black gram for the  
removal of chromium from industrial wastewater. Therefore, in  
the present work, the possible use of the black gram husk for  
the removal of chromium (VI) has been investigated for the  
efficient removal of chromium (VI). The characterization of the  
BGH adsorbent was done by Fourier transform infrared  
spectroscopy (FTIR) analysis. Proximate analysis of the BGH  
was also carried out. The influence of the different process  
parameters like solution pH, adsorbent dosage, initial  
chromium (VI) concentration and contact time was studied.  
Reusability of the prepared adsorbent was also investigated in  
order to check the efficiency of BGH. Besides, the adsorption  
isotherms were also illustrated in the current work.  
10), nanoparticles (11), membrane filtration (12),  
electrochemical technologies (13), and adsorption (14, 15).  
These processes have many disadvantages such as high capital  
Corresponding authors: (a) Sunil Rajoriya, Chemical Engineering Department, Meerut Institute of Engineering and Technology  
Meerut-250005, E-mail: (b) Girish Tyagi, Chemical Engineering Department, Meerut Institute of Engineering  
and Technology Meerut-250005, E-mail: (c) Avdesh Singh Pundir, Chemical Engineering Department, Meerut  
Institute of Engineering and Technology Meerut-250005, E-mail: