INTRODUCTIONWater is one of the most imperative substanceson the Earth. About 75% of our body consists ofwater. Water is used for such a wide variety of purposeslike drinking, washing, bathing, as well as in agricultureand many others industries. According to WorldHealth Organization (WHO) data, about 85% of ruralpopulation lacks potable drinking water. Currently, thewater contamination is serious problem. About 80%of diseases in First world countries are associated withstained drinking water. In Second world countries,15 million infants die annually due to poor hygiene,polluted drinking water, and malnutrition. Chemicalimpurities such as heavy synthetic fertilisers, industrialmetals, dyes of textile industry, and poisonous mineralscan cause hazardous effect on human and animal life.Since these particles are very small in size, they canpenetrate into the ground water [1].Purification of water is a tedious process thatrequires a number of stages [2]. Textile goods are thenecessary need of individuals, while textile industryis of immense economic importance. There are 2324textile industries that require using a number of dyes,additional chemicals, and sizing materials [3]. Differentstages of technological processes of textile dyeingindustry produce huge volumes of waste water. Thewaste water discharged from textile mill includes a largeamount of concentrated industrial dyes.Generally, dye stuffs are complex aromaticsubstances that are difficult to be removed. Methodsused for dye removal include flocculation, chemicalcoagulation, chemical oxidation, photochemicaldegradation, membrane filtration, adsorption, as well asaerobic and anaerobic biological degradation. However,waste after removing dyes reduces light diffusion,affecting thus aquatic plants. In turn, it may be toxic tosome aquatic animals [4]. Moreover, these methods arenot cost effective and environmentally friendly. Noneof them is effective in complete removal of dye fromwastewater [4]. Dyed water not only poses aestheticproblem, but also causes serious ecological problems, forexample, it significantly impacts photosynthetic.Modern studies show that adsorption with the helpof activated carbon is a very efficient method to removevarious organic compounds from the waste water [5].Numerous researchers have searched alternative23Kaur Harpreet et al. Foods and Raw Materials, 2019, vol. 7, no. 2, pp. Х–Хadsorbents deriving them from farming waste or naturalmaterials to remove dyes from wastewater. Some ofthese alternatives are palm ash, orange peel ash, shaleoil ash, pomelo (Citrus grandis L.) peel, fat-free soya,bottom ash, sunflower seed shells, mandarin peel, wheathusk guava leaf powder, as well as steel and fertiliserindustries waste [6].Enormous amounts of fruit peels are disposed, whilethey might be used in the interest of the environment.Agricultural wastes can be employed as a low-costadsorbent for removal of dyes, such as methylene blue,crystal violet, methyl orange, and congo red, fromaqueous solution [6]. Orange peel consists of a largeamount of cellulose, hemi-cellulose, pectin, lignin,and other low molecular weight compounds, togetherwith limestone. It can be used as an efficient and costeffectivebio-adsorbent for removing dyes metals andorganic pollutants from industrial wastewater [7–12].Apart from the traditional methods, there are a numberof recent studies on bioremediation [16–22].Consequently, the aim of the study was to determinethe effectiveness of the combination of plant ash inremoving congo red, crystal violet, methylene blue,and methyl orange dyes from aqueous solution. Theparameters studied were contact time, dye concentrationand pH variation.STUDY OBJECTS AND METHODSMaterials. Glassware and apparatus used: conicalflasks, a round bottom flask, a volumetric flask, funnelmeasuring cylinders, beakers, pipettes, a condenser, asoxhlet apparatus, an electronic weighing balance, anoven, a muffle furnace, a magnetic stirrer pH meter, anda UV-visible spectrometer.Chemical used: AgNO3, ethanol, double distilledwater, methylene blue, congo red, crystal violet, andmethyl orange.Plants used: orange peels, pomegranate peels, bananapeels, drumsticks, and pea pods.Methods. To prepare peel extracts, peels ofpomegranate, orange, banana, and drumstick treeobtained from local market or fruit stalls were cleanedwith distilled water twice to remove dust and watersolubleimpurities. After that, these were cut into smallpieces, and kept for 2 days for proper drying. The driedmaterial was powdered, and extraction was carried outin a Soxhlet apparatus using methanol as solvent.Activated charcoal was obtained by putting the driedplant peels in the muffle furnace at 450–500°C andkeeping the samples to constant weight.The stock solution with a concentration of0.1 g/L was prepared for different dyes. The differentconcentrations of the dye solutions were obtained fromthe stock solution by dilution method. Methylene blue,congo red, crystal violet, and methyl orange were usedas adsorbates.Kinetics study was performed as follows. 0.6 g ofadsorbent was added into 250 mL conical flasks filledwith 100 mL of diluted solutions (25–200 mg/L). Thesolutions were stirred constantly, and the concentrationof dye at maximum wavelength was measured using adouble beam UV-visible spectrometer. The capacity ofdye adsorbed at time t, Qt (mg/g), was calculated by thegiven formula:Qt = (A0–At) v/W (1)where At is concentration at time t, A0 is the initialconcentration, v is volume of solution, and W is theweight of adsorbent used [13].To study the dependence of initial concentration ofdyes and contact time on the degree of removing dyes,0.6g of each sample (orange, banana, and pomegranateash) was added to each 100 mL flask with various dyeshaving different concentrations. The solution was stirredon the magnetic stirrer at room temperature. The timerequired for complete adsorption was determined.RESULTS AND DISCUSSIONDifferent dyes, namely, methylene blue, congo red,crystal violet, and methyl orange were taken to evaluatethe adsorption capacity of the adsorbent.According to Figs. 1–4, the effectiveness of dyeremoval increased with an increase in time. This mightbe due to the better interaction between dye moleculesand those of activated charcoal. It was observed that theinitially dye removal occurred faster and followed firstorder kinetics. This was proportional to the availabilityof active sites, and an equilibrium between adsorptionand desorption was than established.The absorbance of methylene blue at λmax (about390 nm) decreased with increasing contact time (Fig. 1).The complete absorbance of methylene blue with theadsorbent took 60 min.The variation of absorbance of crystal violet withtime was studied by a UV-visible spectroscopy (Fig. 2).Crystal violet exhibited λmax at 390 nm. It was found thatthe dye was completely removed after 30 min of contactwith adsorbent.Figure 1 Absorbance of methylene blue at different contacttimeFig 1: Absorbance of methylene blue at different contact time0.000.040.080.12200 300 400 500AbsorbanceWavelength, nmMB(0.01) 20 min 30 min40 min 50 min 60 min24Kaur Harpreet et al. Foods and Raw Materials, 2019, vol. 7, no. 2, pp. Х–ХSimilarly, congo red was completely removed in40 min of contact with the adsorbent (Fig. 3).On the contrary, the adsorbent was not effectivefor methyl orange removal (Fig. 4). Even two hours ofcontact time was not enough to adsorb the dye. Thiscould be due to the fact that methyl orange does not haveany functionality that could make the Vander Waals’interaction with the adsorbent.The successful removal of various dyes by thecombination of plant ashes proved the efficacy of thecombination for bioremediation of textile water. Asseen from Figure 5, complete dye removal took 5 h. Thetextile effluent water contained a large amount of heavymetals and different kinds of dyes, so it took longer foradsorbent to absorb the colourant.Adsorption coefficient of activated charcoal fordifferent dyes at time t. Adsorption coefficient wascalculated as the amount of dye adsorbed with onegram of the adsorbent (mg/g). Adsorption coefficientwas found to be different for each dye (Table 1) becauseadsorption depended upon the compatibility of thedye structure with the surface and the porosity of theadsorbent. It was found that absorption capacity forFigure 2 Absorbance of crystal violet at different contact timeFigure 3 Absorbance of congo red at different contact timeFigure 4 Absorbance of methyl orange at different contacttimeFigure 5 Absorbance of textile raw water at different timeof contactFig 1: Absorbance of methylene blue at different contact timeFig 2: Absorbance of crystal violet at different contact timeFig 3: Absorbance of Congo red at different contact time0.000.040.080.12200 300 400 500AbsorbanceWavelength, nmMB(0.01) 20 min 30 min40 min 50 min 60 min0.000.100.200.300 100 200 300 400 500 600AbsorbanceWavelength, nm0 min 15 min 20 min30 min 35 min 40 minFigure 6 Contact time of different dyes at dye concentrationof 0.015-0.050.100.250.400.550 100 200 300 400 500AbsorbanceWavelength, nm0 min 10 min 40 min80 min 120 min0.00.51.01.52.0400 Absorbance0 hour 3.5 04080120Crystal Violet Methylene Blue Congo Red Methy OrangeTime(min)-0.050.100.250.400.550 100 200 300 400 500AbsorbanceWavelength, nm0 min 10 min 40 min80 min 120 min0.00.51.01.52.0400 500 600 700 800AbsorbanceWavelength, nm0 hour 1 hour 2 hour 3 hour3.5 hour 4.5 hour 5 hour04080120Crystal Violet Methylene Blue Congo Red Methy OrangeTime(min)-0.050.100.250.400.550 100 200 300 400 500AbsorbanceWavelength, nm0 min 10 min 40 min80 min 120 min0.00.51.01.52.0400 500 AbsorbanceWavelength, 0 hour 1 hour 3.5 hour 4.5 hour 04080120Crystal Violet Methylene Blue Congo Red Methy OrangeTime(min)Methyl methyl orange was significantly lower, whereas that forcongo red had maximum value at contact time of 30 min(Fig. 6).Percentage of dyes adsorbed with adsorbent. Thepercentage of dye elimination indicated the efficiencyof adsorbent (Table 2). The results made it possibleto conclude that 100% of congo red was removed in40 min, whereas the removal of only 48% of methyl2.421.61.20.80.400 200 400 600-0.050.100.250.400.550 100 200 300 400 500AbsorbanceWavelength, nm0 min 10 min 40 min80 min 120 min0.00.51.01.52.0400 500 600 700 800AbsorbanceWavelength, nm0 hour 1 hour 2 hour 3 hour3.5 hour 4.5 hour 5 hour04080120Crystal Violet Methylene Blue Congo Red Methy OrangeTime(min)-0.050.100.250.400.550 100 200 300 400 500AbsorbanceWavelength, nm0 min 10 min 40 min80 min 120 min0.00.51.01.52.0400 500 600 700 800AbsorbanceWavelength, nm0 hour 1 hour 2 hour 3 hour3.5 hour 4.5 hour 5 hour04080120Crystal Violet Methylene Blue Congo Red Methy OrangeTime(min)C.V 0.015 10 min 20 min25 min 30 min25Kaur Harpreet et al. Foods and Raw Materials, 2019, vol. 7, no. 2, pp. Х–Хorange took 120 min. In spite of the fact that both methylorange and congo red dyes have similar structure, thepercentage of their removal from the solution differs.One of the causes for that could be the presence oftwo primary amine groups in congo red, which couldcontribute to binding of dye with adsorbent. Thus, thestructure of adsorbate played a crucial role in adsorptionefficacy. The efficiency of adsorption depended uponthe pore size of the adsorbent. The results of the studyconfirmed that the structure of congo red dye was wellmatchedwith the pore size of the adsorbent, whichallowed it to exhibit fairly efficient adsorption (Table 2).pH of dyes after treatment. The change in pH ofdifferent dye solutions was studied before and after thetreatment with adsorbent. As one can see from Table 3,pH of the solution increased after the treatment. It couldbe due to introduction of basic component from theactivated charcoal to the dye solution. Additional workcould be done to find out the reason for the same.Characteristics of the adsorbent. The adsorbentwas analysed by Fourier transform infraredspectroscopy (FTIR) and scanning electron microscopy(SEM). The FTIR spectrum of the activated charcoalTable 1 Adsorption coefficient of dyes at contact time of 30minDye Structure of dyes Adsorptioncoefficient,mg/gCongoRed2.33MethyleneBlue1.00CrystalVioletN+NNCl-1.66is shown in Figure 7. The various peaks were observeddue to different functional groups. The peak at about2200 cm–1 could be due to the presence of sp hybridisedcarbon. The peak at 1660 cm–1 corresponded to aromaticC=C stretching. The peak value at 3166 cm–1 indicatedthe presence of C-H group.Surface morphology revealed the adsorbent hadporous structure. This could be due to the evaporationof the chemical reagent throughout the carbonisationprocess, leaving the vacant spaces on the surface of theadsorbent. It is obvious from the SEM image (Fig. 8)that the adsorbent is a mixture of activated charcoalprepared from dissimilar plant material. The presenceof dissimilar plant materials in the adsorbent could beaccountable for elimination of broad range of dyes bothcationic and anionic.Characteristics of the adsorbent after adsorption.The FTIR analysis of adsorbent after reaction with dyeshowed a number of additional peaks, perhaps due to thefunctional groups present in the dye that was adsorbedonto the adsorbent.FTIR spectrometry demonstrated one additionalvibrational peak at 1386.61 cm–1, which can be due toC-N stretching. The stretching vibration was observed at872.88 cm–1 due to the presence of C-Cl bond. The C-Sstretching band was observed at 572 cm–1. Every newpeak definited that methylene blue was adsorbed on theactivated charcoal by assembling altered kinds of bonds.Table 2 Percentage removal of dyesDye Concentration,g/LTime,minDyeremoval, %Congo red 0.015 40 100Methylene blue 0.015 120 100Crystal violet 0.015 60 100Methyl orange 0.0025 120 48Table 3 pH of dye solutions before and after treatment withadsorbentConcentrationCongo red CrystalvioletMethyleneblueMethylorangeT1 T2 T1 T2 T1 T2 T1 T20.015 7.34 10.90 8.50 10.00 7.70 10.30 7.57 9.740.01 7.30 10.06 7.50 10.12 7.43 10.25 7.50 –0.005 7.20 10.02 7.30 10.24 7.39 10.21 7.40 –0.0025 7.12 9.85 7.10 10.27 7.20 9.74 7.25 –SD = ± 0.05T1 – before treatment; T2 – after treatmentFigure 7 Infrared spectra of activated charcoal0.050.100.250.400.550 100 200 300 400 500Wavelength, nm0 min 10 min 40 min80 min 120 min0.00.51.01.52.0400 500 600 700 800AbsorbanceWavelength, nm0 hour 1 hour 2 hour 3 hour3.5 hour 4.5 hour 5 hour04080120Crystal Violet Methylene Blue Congo Red Methy Orange26Kaur Harpreet et al. Foods and Raw Materials, 2019, vol. 7, no. 2, pp. Х–ХThe FTIR analysis of activated charcoal afteradsorption of crystal violet revealed no additional peaks(Fig. 10). One of the causes can be crystal violet insertedin pores.As for the FTIR spectra (Fig. 11) of activatedcharcoal with adsorbed congo red dye, three additionalpeaks were observed. Those were recorded at 3463,2514, 1795, and 603 cm–1 that were due to N-Hstretching, O-H stretching of carboxylic acid, C=Ostretching, and C-C bending due to alkane, respectively.The presence of these functional groups confirms theadsorption of congo red dye on the activated charcoal.Figure 9 Infrared spectra of activated charcoal afteradsorption of methylene blueFigure 10 Infrared spectra of activated charcoal afteradsorption of crystal violetFigure 11 Infrared Spectra of activated charcoal afteradsorption of congo redCONCLUSIONThe results of this study made it possible to concludethat activated charcoal prepared from mixture of orange,banana, and pomegranate peels by carbonisation methodhad a great potential for removal of dyes from textilewastewater. In the present work, this adsorbent wastested on congo red, methylene blue, crystal violet, andmethyl orange dyes. Studies showed that this adsorbentwas effective in removing congo red, methylene blue,and crystal violet dyes from aqueous solutions, whileit was not quite capable of removing methyl orange.Surface chemistry of activated carbon played animportant role in dye adsorption. The type of the dyeadsorbed on the adsorbent also depended on its texturalmin0.00.51.01.52.0400 500 600 700 800AbsorbanceWavelength, nm0 hour 1 hour 2 hour 3 hour3.5 hour 4.5 hour 5 hourRed Methy OrangeFig-10: Infrared spectra of activated charcoal after adsorption of crystal violetFig.11: Infrared Spectra of activated charcoal after adsorption of congo red0Crystal Violet Methylene Blue Congo Red Methy OrangeTime(Figure 8 SEM image of the activated charcoal27Kaur Harpreet et al. Foods and Raw Materials, 2019, vol. 7, no. 2, pp. Х–Хproperties, such as porosity and surface area. Theadsorbent under study gave the best result for congo reddye. Thus, the present research developed a low-coat andenvironmentally friendly technology to remove dyes,as an alternative to known expensive and damagingmethods.