Qualitative analysis of acid washed black cumin seeds for decolorization of water through removal of highly intense dye methylene blue

Dyes in water change the colour, taste and odour of water, are highly visible, and can be toxic and cancerous for the coloured water consumption human beings. Basic dyes particularly, methylene blue, MB has high colour intensity, shows intense colour even at low concentration, and are very toxic due to their complex structure. Instead of adsorption, removal of MB from water using various traditional treatment methods is costly and less effective. The use of bioadsorbent provides easy and low cost technique for removal of MB. For searching the adequate technique of dye removal, adsorption efficiency and mechanism of bioadsorbent can be analyzed. To this, MB removal efficiency of seeds of medicinal plant, black cumin seeds were analyzed. The data are supplied in the article.


a b s t r a c t
Dyes in water change the colour, taste and odour of water, are highly visible, and can be toxic and cancerous for the coloured water consumption human beings. Basic dyes particularly, methylene blue, MB has high colour intensity, shows intense colour even at low concentration, and are very toxic due to their complex structure. Instead of adsorption, removal of MB from water using various traditional treatment methods is costly and less effective. The use of bioadsorbent provides easy and low cost technique for removal of MB. For searching the adequate technique of dye removal, adsorption efficiency and mechanism of bioadsorbent can be analyzed. To this, MB removal efficiency of seeds of medicinal plant, black cumin seeds were analyzed. The data are supplied in the article.
& 2018 Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Subject area
Environmental Chemistry More specific subject area Adsorption Type of data

Value of the data
Black cumin seeds are highly porous, amorphous and have large functional sites. High rate and efficiency of removal of methylene blue from water. Low quantity of black cumin seeds is sufficient.

Experimental design
Black cumin seeds were washed with inorganic acid, hydrochloric acid. Surface and particles properties of acid washed black cumin seeds were analyzed by FT-IR, XRD, SEM-EDX and TEM [1] (Table 1). Scheme 1. : Proposed mechanistic pathway for electrostatic and hydrogen bonding interactions between MB and AWBC.

Washing of black cumin seeds
The washed, dried and grounded, seeds of black cumin were washed with common inorganic acid, Hydrochloric acid (HCl) as per the method reported literature [1,2] to leach out the others elements attached on their surface.

Determination of surface properties of black cumin seeds
FT-IR spectrum analyzed for the functional groups present on the surface of AWBC which acted as adsorptive sites for MB molecules. The diffraction peaks in XRD pattern of AWBC were used to analyze the amorphous nature of the AWBC. SEM and TEM images are given for the porous and heterogeneous surface of AWBC, respectively. EDX pattern were analyzed for chemical composition of AWBC. The graph between ΔpH ¼ pHi-pHf and pHi gave the zero point charge of AWBC [1].

Batch adsorption experiments
Batch adsorption experiments were carried out by agitating (at 215 rpm) the series of 50 mL of Erlenmeyer flasks having 10 mL of MB dye solution of an initial concentrations varying from 10 to 60 mg L À 1 and 1 gL À 1 of AWBC for contact time of 0-120 min at neutral pH, and room temperature. The concentration of MB in the solution before agitation and after agitation was estimated by analyzing their absorbance using ultraviolet-visible (UV-vis) spectrophotometer at 660 nm. These estimated initial, C o and final concentrations, C e of MB solution, respectively, gave the uptake capacity as follows [3][4][5]: where, V is the volume of MB solution in liter and m (g) is the amount of AWBC.
Ultimately, adsorption data obtained from above study was verified by fitting in various isotherms, kinetic and thermodynamic relationships [6,7] to design the appropriate water treatment system using bio-adsorbent [1].