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:: Volume 10, Issue 1 (Winter 2021) ::
Arch Hyg Sci 2021, 10(1): 30-48 Back to browse issues page
‎Application of Box-Behnken Design and Response Surface Methodology of Acid Red 18 Adsorption onto PAC‎ (Synthesized Carrot Waste) Coated with Fe3O4 Nanoparticles from Aquatic Solution: Kinetic and Isotherm Studies
Roya Moradi , Morteza Kashefialasl * , Reza Marandi , Esmael Salahi , Shahram Moradidehaqi
Associate Professor, Department of Environmental Pollution, Faculty of Marine Science and Technology, Islamic Azad University, North Tehran Branch, Iran
Keywords: Adsorption, Isotherm, Kinetics, Ponceau 4R, Solutions, Synthetic activated carbon.
Full-Text [PDF 1523 kb]   (33 Downloads)     |   Abstract (HTML)  (88 Views)
Type of Study: Original Article | Subject: Environmental Health
Received: 2020/09/20 | Accepted: 2020/11/7 | Published: 2021/01/19
Full-Text:   (18 Views)

Adsorption, among all these methods aBackgroundBackgroundnd techniques, has been revealed to have the highest potential to remove dye effectively from wastewater. The reason for such capacity is related to adsorption’s low cost of production, unambiguous design, easy operational procedure, and unresponsiveness to substances that are toxic in nature. Activated carbons (ACs), due to their high capability of adsorption, are considered the most widely used adsorbing agent with a very high level of success (7). In this regard, since AC can remove dyes effectively, it can be considered one of the best options for this process. Activated carbon, as an adsorbent, has important and vital applications. This substance is produced from the pyrolysis of plant substances containing carbon and is subjected to activation operations. Activated carbon has different pores and shapes, depending on the type of used raw materials, showing a wide range of specific applications regarding the distribution of pores. Carbon can be extracted from such sources as corn stalks, wheat husks, reeds, sesame, and fruit kernels, as well as the skin of some seeds, such as hazelnuts, almonds, and coconuts (8).

Today, more attention is focused on getting cheaper and more available adsorbents. Pectin is the main form of soluble fiber in carrots, which is a strong bonding agent. Carrot has a high adsorption capacity due to the presence
of such components as polysaccharides, oligosaccharides, and lignin (9). The adsorption techniques on powders or granular materials, especially AC, are among the most used and easiest ones to implement. However, the applicability of this method is limited by the production costs and regeneration of the aforementioned materials. Therefore, in recent years, interest has focused on finding low-cost adsorbent materials (e.g., bio adsorbents, biochar, and AC) through recycling and turning them into by-products or industrial wastes (10). Response surface methodology (RSM) is a combination of methods in math and statistics to analyze the effects of several independent factors on the dependent factor, which provides functions and data to code and decode factor levels (11). This method is highly used in the adsorption process design and its optimization, which has been used in this study as well.


Materials & Methods



To synthesis waste carrot, 1.4 Tesla magnet,


Table 1) Acid Red18 dye characteristics

λ max (nm)

Mw (g/mol-1)

Molecular Structure

Molecular Formula

Color index name

Chemical structure



Single azo class


Acid Red 18



ethanol 98%, Sodium hydrogen carbonate (NaHCO), Fe3O4 (ferric chloride (FeCl3·6H2O), ferrous chloride (FeCl2 4H2O), ammonium persulfate (S2O8 (NH4)2), sulfuric acid (H2SO4) were purchased from Merck Company, Germany. Acid red18 dye was also purchased from Merck (Table 1). The pH was adjusted with NaOH and HCl solution (0.1 mol L-1). The reagents used in this research all had an analytical grade. The determination of AR18 dye in solutions was performed with the aid of
a Cary 100 Bio Spectrophotometer device (Varian, USA). Powder X-ray diffractometer (Philips PW-3710) was used for X-ray diffraction (XRD) patterns recording with Cu as
a source of X-ray ( 1.5406 Å). The energy dispersion and synthesized PAC (Synthesized Carrot Waste) morphology were investigated using field emission scanning electron microscopy (FESEM) device (VEGATESCAN-LMU, TESCAN, Brno, Czech Republic). The images created by high-resolution transmission electron microscopy (TEM) were recorded using a microscope (Tungsten Hairpin EM208S, FEI, USA) at 100 kV operational mode. Fourier-transform infrared (FTIR) spectroscopy of the PAC (synthesis Waste carrot) was recorded both before and after dye adsorption. The applied range on an FTIR spectrometer (Spectrum 400, Perkin Elmer, USA) was 4000-400 cm-1. The adsorption rate and adsorption porosity were measured using Brunauer–Emmett–Teller (BET) analysis (BELSORP-mini II, BEL Japan Inc., Japan).


Activated carbon preparation

The AC was prepared by physical activation in a single step. To prepare and synthesize nano-adsorbent, after that 1 kg carrot waste was washed with distilled water for 2 h, it was placed in an oven at 105°C  to reach 0.0% of humidity. Subsequently, it was mixed with concentrated sulfuric acid 0.5 M and Ammonium persulfate 0.1 M with a ratio of 1:1 (weight: volume) to obtain activate carbon and placed in an oven at 250°C for 5 h (12). At the next stage, NaHCO was added up to 1% to remove the acid vapor from the carbon pores. The AC was washed with distilled water several times to remove the bicarbonate and neutralize the carbon from the alkaline state. Afterward, the AC was put into an oven at 105°C for 24 h (13). To remove other impurities, the product was dissolved in 18% hydrochloric acid solution at room temperature for 16 h. Finally, the product was dried in an oven at 105°C, and 200 g of AC was obtained from carrot waste (14).

In order to produce porous nanocarbon, 100 g of AC was milled with a mortar and put in a 37-µm sieve. During this process, 150 g of AC passed and 50 g of it was milled for 60 min (Planetary Ball Mill, Retsch, Germany) (15). About 0.5 g of AC from carrot waste was dissolved in 70 mL of water by ultrasonic irradiation for 20 min. The mixture was further stirred vigorously for 30 min at 60°C. Subsequently, 177 mg of FeCl3+/FeCl2+ salts in the mass ratio of 2:1 was added under stirring. The mixture was stirred vigorously for 30 min under N2 atmosphere, followed by the highly slow addition of 30 mL of  NH4OH 6% solution into the mixture at 60°C within 1 h and extended for another 2 h. To prevent oxidation, the N2 atmosphere was applied during the experiment. The mixture was then centrifuged, washed with double distilled water, and dried. The obtained black precipitate was Fe3O4/AC from carrot waste nanoparticles ready for use (16). The particles were then placed in a nitrogen furnace at 800oC for 3 h to be carbonized and charged under the nitrogen gas of iron nanoparticles on carbon since the 1.4 Tesla magnet absorbed them easily. The induction of magnetic nanoparticles in the adsorbent tissue was essential. The following formula shows the steps of construction and separation of the adsorbent: