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Research Subject: Removal of industrial wastewater especially from textile and dyeing factories is always important actions to control of pollutions. Using of polymeric adsorbents is an important method for removal of dyes from industrial wastewater. In this research work, designing and fabrication of PVA-based adsorbent with proper potential for removal of green malachite from industrial wastewater has been reported.
Research Approach: For fabrication of adsorbent 4 wt.% PVA was gelled in the present of 10 wt.% glutaraldehyde as cross-linker and punched. The punched hydrogels were porous with freeze drying method. For improving the adsorption ability, graphene and TiO₂ were used. The adsorption of green malachite with prepare adsorbent was measured timely to determine the optimum percentage of nanoparticles. In addition, the effect of contact time and the presence of UV on the adsorption of pollution was investigated. Finally, the adsorption isotherms and thermodynamics study were investigated in different time.
Main Results: The results of adsorption of pollution with PVA/graphene adsorbent in different times showed that 0.5 wt.% is the optimum loading of graphene in the PVA matrix. This value was 3 wt.% for TiO₂. The adsorption percentage via optimum adsorbent in dark condition showed that one minute after addition of adsorbent the adsorption percent increased to 75% indicating the high capability of the adsorbent in adsorption of tested pollution. The porous structure was confirmed via SEM image. By comparing the correlation coefficient for Langmuir and Freundlich isotherms it was found that Freundlich isotherm has better agreement with the findings of the current study. In other words, adsorption of green malachite with fabricated adsorbent was done multi layered. The thermodynamics studies showed that due to negative value of Gibbs energy the adsorption reaction of green malachite with fabricated absorbent is automatically.

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Research Subject: In this paper, the adsorbents used to remove lead ion using adsorption operation have been reviewed.
Research Approach: The types of adsorbents used to remove lead ions, the modifications of adsorbents, adsorption conditions, isotherms and adsorption capacity of adsorbents have been investigated and compared based on the literature survey.
Main Results: Modification by impregnation of functional groups has a significant role in increasing the adsorption capacity. The pH of the solution plays an important role in the adsorption of lead ions and generally the adsorption capacity increases by increasing the pH of the solution. Langmuir's isotherm model has been more consistent with the equilibrium data. Among the reviewed adsorbents, carbon-based adsorbents such as activated carbon and graphen-oxide, modified by chemicals such as ammonium persulfate or polyamines, show higher adsorption. Also, biomasses due to their abundance and low prices have the potential to be used as lead ion adsorbents.

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Research subject: In recent years, due to limited water resources and the extraordinary increase in nitrates in the environment, efforts to remove and control in order to benefit from the natural adsorbents have been made. Although according to the negatively charged surface of bentonite particles, absorbent needs improvement.
Research approach: In the current study, the adsorption of nitrate columns by the modified calcium montmorillonite adsorbent was investigated. Furthermore, In order to change the surface load and increase the adsorption efficiency, three-step acid leaching, oxidation layering, and loading of the cationic surfactant hexadecyltrimethylammonium bromide on the adsorbent were performed. Molecular interaction and crystallography of pure montmorillonite and synthetic nano-adsorbent (ACZ) were characterized by Fourier transform infrared spectroscopy and X-ray analysis. Moreover, the morphology of ACZ nano adsorbents was evaluated using Transmission electron microscopy and scanning electron microscopy.
Main results: Nanoparticle compaction and less access to pores and cavities in the fixed bed column reduced the adsorbent capacity inside the column compared to the discontinuous system.
The results showed that an increase in inlet concentration from 80 to 150 mg/L increased the adsorption capacity from 67.39 to 88.25 mg/g. Reducing the inlet flow rate increased the penetration time, interaction, and greater access to the binding sites for nitrate ions and finally improved the column performance and increased the inlet flow rate reduced the adsorption capacity and breakthrough time. Therefore, the adsorption of nitrate ions by the stage of internal mass transfer is controlled and depends on the duration of interaction and the possibility of penetration into the active sites. With increasing the bed height from 4.2 to 9 cm, there was a significant increase in adsorption capacity from 60.608 to 77.167 mg/g. The effect of detergents and recovery showed an absorption column; After 3 leaching steps, acid leaching played an important role in increasing column recovery. Experimental data with correlation coefficients of R²>0.95 corresponded to Thomas and Yoon-Nelson kinetic models.
In this study, the ACZ nano adsorbent column for rapid removal of nitrate ions from aqueous solutions was introduced and for use in reusable systems was proposed.
 

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Pepper plant Capsicum annuum L. has great nutritional value and many pharmaceutical properties but its sensitivity to pests such as Aphis gossypii Glover, especially in drought stress conditions, has limited its production. To evaluate the effect of drought stress on the population and damage rate of this pest in greenhouse condition, four moisture treatments including; full irrigation, 15, 30 and 45 percent of water deficit, and four treatments with different amounts of super absorbent polymer (SAP) containing 2, 4, 6 and 8 g per pot were separately performed in completely randomized design. Four weeks after applying drought stress, the pots were moved near the aphid sources. Density of aphids was examined after one month of infestation, and the plant growth characteristics after two months. It was found that the increase in severe drought stress (45% DI₄₅) significantly raised the population of this pest and remarkably decreased plant growth rate and yield. However, the low stress of drought (15% DI₁₅) not only caused relative reduction of insect’s population, but also saved water consumption and increased crop yield. However, the insect population was elevated as a result of increase in the amount of irrigation. Although the excessive use of SAP (8 g) increased the aphid population, the current experiment showed the use of 4 and 6 g of super absorbents could minimize the irrigation stress, decrease the pest population and improve yield of the plants by retaining the moisture in drought conditions.

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Research subject: Activated carbon is a porous absorbent with reasonable specific surface area, pore volume, and pore size distribution for many applications such as adsorption. This material is obtained from various natural sources of carbon. Due to increasing demand for activated carbon, the economical precursors have been highly noticed. In the meanwhile, black liquor, industrial residue from Lignin Kraft process in paper factories, has high amount of carbon which can be used as an appropriate and cheap precursor for activated carbon production, and make high value added.
Research approach: In this study, at first, lignin was extracted from black liquor, prepared from Iran wood & paper industries-Chouka factory, under defined conditions and investigation of pH effect, and then, powdered carbon was synthesized from extracted lignin using chemical activation method by phosphoric acid chemical agent. To consider the effects of activation temperature parameter on activated carbon structure, including specific surface area, pore volume, and pore size distribution, three activation temperature of 400, 500 and 600 ^⁰C in impregnation ratio of 2 were investigated. To study the physical and morphological properties of sensitized absorbents, they were analyzed by BET, SEM, and FTIR methods.
Main results: The results confirmed that the highest amount of lignin with a similar structure to the degraded lignin was recovered at pH = 2. Investigation of the effect of activation temperature parameter suggested that the activation temperature of 500 ^°C can be a reasonable temperature for the synthesis of high specific surface area activated carbon and increasing the temperature above 500 ^°C is not effective. Among these sensitized adsorbents, the activated carbon sensitized in activation temperature of 500 ^⁰C showed the highest specific surface area and the pore volume of 1573.31 m²/g and 0.89 cm³/g respectively, which exhibits the high potential of this precursor as activated carbon adsorbent.

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Contamination of water and soil with heavy metals poses serious risks and threats to human health and the environment, and therefore finding an effective solution to remove these metals is very necessary. In this research, magnetic nanoparticles MnFe₂O₄ @ SiO₂ functionalized with N-phosphonomethyl aminodiacetic acid with core-shell structure were synthesized. These nanoparticles were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, (TGA) thermal gravimetric analysis, transmission electron microscope (TEM), and (VSM) vibration sample magnetometer. The performance of this synthetic nanoadsorbent for removing Cr (VI), Cu (II) ions from aqueous solutions was evaluated by various parameters such as adsorbent amount, contact time effect on adsorption rate and pH effect. The results show that the adsorption efficiency increases with raising pH (2.5-5) and the best adsorbent performance in the adsorption process of Cr ((VI) and Cu (II) ions at pH 7 was observed. The amount of R in the Freundlich adsorption diagram of copper ion is higher than the Langmuir isotherm. As a result, the adsorption of copper ions on the adsorbent follows the Freundlich adsorption equation. In addition, the amount of R in the Freundlich adsorption diagram for chromium ion is higher than the Langmuir isotherm. Therefore, the absorption of chromium ions on the adsorbent follows the Freundlich adsorption equation. In conclusion, a high n value indicates a favorable and effective absorption in the Freundlich equation. The adsorption data were analyzed by the Langmuir and Freundlich isotherm model. In addition, the recyclability and reuse of the adsorbent was investigated. The results show that no significant reduction in adsorbent activity is observed.
 

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Aim Land use change (LUC) not only affects the plant and soil functional properties, but also influences soil nutrients efficiency. This research was carried out to examine the effect of grassland conversion to dry farming on the efficiency of bio-mineral nutrients in semi-arid loamy soils of northwestern Iran.
Materials & methods Animal manure (AM: 100 and 200 g. Kg^-1), useful micro-organisms (UMOs: 1 and 2%), superabsorbent polymers (SAP: 10 and 30 g. Kg^-1) and potassium nano-silicate (PNS: 500 and 1000 mg. Kg^-1) were used for grass Festuca ovina L. cultivated in grassland and dry farming soil at a completely randomized factorial design.
Findings Based on the results, LUC strongly affected the efficiency of soil nutrients especially PNS (P ≤0.01) where the highest and lowest effects of different nutrients were observed under dry farming and grassland, respectively. A maximum difference of 24.0%, 45.0% and 24.0% were observed in plant biomass, chlorophyll, moisture content, respectively, using 200 g. Kg^-1 AM and 30 g. Kg^-1 SAP in soil of grassland and dry farming. Also, maximum difference of 71.0% and 67.0% occurred at soil phosphorus and organic matter, respectively between grassland and dry farming.
Conclusion depending on the type and amount of fertilizer, convert the grasslands to rainfed areas significantly influence plant performance and soil improvement. Overall, due to the undisturbed soil, grasslands show a better performance than rainfed areas under any rehabilitation program.

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The purpose of this survey was to evaluate natural occurrence and content of Aflatoxin M1 (AFM1) in dairy products marketed in Urmia (Iran). During September 2007, 40 samples of pasteurized milk, 40 samples of Ultra High Temperature Treated (UHT) milk, 40 samples of creamy cheese and 40 samples of Iranian Feta cheese were collected from different supermarkets in Urmia city. AFM1 contents were determined through competitive Enzyme Linked Imunosorbent Assay (ELISA) technique. All milk samples analyzed showed mean AFM1 concentrations lower than the permissible level of 50 ng L-1 (23.22±8.65, and 19.53±7.47 ng L-1 in pasteurized milk, and UHT milk, respectively). The mean levels of AFM1 contamination were 43.31±18.51 ng L-1 in Feta cheeses, 21.96±3.23 ng L-1 in creamy cheeses. The potential risk of human exposure to aflatoxin M1 via consumption of milk and milk products is well known. Therefore, dairy products must be evaluated for aflatoxin and kept apart from fungal contamination as much as possible.

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Abstract: Water pollution due to toxic heavy metals has been a main cause of concern for the environmental engineers. Heavy metals are individual metals that negatively affect people's health. In very small amounts, many of these metals are necessary to support life. However, in larger amounts, they become toxic. Lead is one the important heavy metals that is applied in different industries such as manufacture of batteries, metal products and ammunition. Its standard limits in drinking water are 0.05 mg/L, because it affects all organs and functions of the body to varying degrees. The frequency and severity of symptoms among exposed individuals depends upon the amount of exposure. Lead entering the respiratory and digestive systems is released to the blood and distributed throughout the body. It is stored and may be released into the blood, re-exposing organ systems long after the original exposure. This is why the wastewater includes lead should be treated before discharging to the environment. Different kinds of physical, chemical and biological methods are used to remove lead. The main techniques are including precipitation, ion exchange, adsorption, membrane processing and electrolyte methods. Adsorption with many advantages is a proper method that is applied to treat heavy metal removal. In recent years, use of low cost materials as adsorbent for metal ion removal has been highlighted. Since natural absorbents are inexpensive and may be achieved without any cost and they are usually in abundance in nature, absorption of solute ions by these materials are a proper method to eliminate heavy metals from polluted waters and industrial wastewaters. In this study, following continuous column method, sawdust and ash, as two absorbents were used for removing lead. The experiments were carried out with the initial pH of 5 and different densities (50 and 100 ppm). In order to optimize the process of adsorption, three combined absorbents were also used which made from the above two absorbents with the ratios of 1:3, 1:4 and 1:6. Batch experiments were carried out in order to determine the parameters of adsorption. The results of sorption with sawdust have shown that Langmuir adsorption isotherm were suitable. Based on the results of the column experiments study, lead removal efficiency was more than 98 percent when combined absorbents were used. In batch experiments, the percent efficiency was 76 and 98 percent with sawdust and ash, respectively.

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Most of dyes used in production processes caused serious environmental pollution when discharged to the water resources. Azo dyes are the most used synthetic compounds in the industries such as textile, food, leather and cosmetic. Due to their toxicity and hard degradation, these kinds of compounds are classi fied as environmental hazardous materials that have to be treated before discharging to the environment. Direct blue 71 (DB 71) is one of azo dyes that is resistant to aerobic degradation and under anaerobic condition is reduced to potential carcinogenic aromatics. Different kinds of physical, chemical and biological methods such as adsorption, ultra filtration, reverse osmosis, coagulation and electro coagulation are widely used for efficient dye removal but they just transport contaminants from water to sludge and generate secondary wastes which need more treatment. Adsorption with many advantages is a proper method that is applied to treat dye compounds. In recent years, use of low cost materials as adsorbent for dye removal has been highlighted. Since natural absorbents are inexpensive and may be achieved without any cost and they are usually in abundance in nature, absorption of solute ions by these materials are a proper method to eliminate color from polluted waters and industrial wastewaters. In this study, removal of azo dye Direct Blue 71 was evaluated with two new natural adsorbents of walnut and peanuts shells. These adsorbents are produced from agricultural wastes. The effect of pH, contact time and adsorbent dosage on the removal efficiency has been studied. According to the results, maximum removal of dyes by the two natural absorbents (0.75 gr/L walnut shell in 50 mg/L initial dye concentration with pH of 9 in 45 minutes and 1 gr/L peanut shell in 50 mg/L initial dye concentration with pH of 9 in 60 minutes) was 55 and 60 percent, respectively. Comparison of prepared adsorbent in the laboratory and commercial ones in optimum condition have similar dye removal efficiency that means suitable and cheap adsorbent could be prepared in the laboratory. Removal efficiency of DB71 was also obtained 85 and 83 by the two walnut and peanut shells adsorbent powder, respectively. The results have also shown that amongst four isotherms of Langmuir, Freundlich, Temkin and Dubinin-radushkevich, Freundlich isotherm has the highest correlation coefficient which implying heterogeneous surface of adsorbent for both sorbents. It has also shown that the maximum surface adsorbent capacity for the monolayer of activated carbon of the walnut and peanut shells were 26 and 28 mg/gr, respectively. From the n values 3.58 and 3.72 of the Freundlich isotherm for both adsorbent of walnut and peanut shells, it could be concluded that physical adsorption process has been happened. The data could also indicate that pseudosecond- order was the best adsorption kinetics model for the two adsorbents

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In the present study, for the first time, adsorbent bed of SWS-1L/water adsorption chiller with rectangular and trapezoidal finned flat-tube heat exchanger with has been simulated three dimensionally based on the distributed parameters model and finite volume method. Effects of some important parameters on the chiller performance such as bed averaged pressure, temperature and uptake variations with cycle time have been examined for better understanding of bed dynamic behavior. Also, a comparative study between two different configurations of adsorbent bed including rectangular and trapezoidal fins has been conducted based on identical adsorbent mass. For this purpose, bed temperature, uptake and pressure distributions as well as the vapor flow patterns at the end of heating cycle phases and also effects of fin height and spacing on the system performance have been studied. In this investigation at fixed bed length of 20mm, fin height and spacing variations have been examined in the range of 8-20mm and 3-12mm, respectively. Results indicated that the system performance with rectangular and trapezoidal adsorbent beds are almost similar except for those conditions which fin spacing is 3mm and fin height are 14, 20mm. For the mentioned dimensions, the specific cooling power (SCP) of rectangular beds are almost 5% and 17% (for fin heights of 14 and 20mm, respectively) better than those of trapezoidal beds. Maximum and minimum SCP of adsorption chiller with flat-tube heat exchanger were obtained about 882 and 163W/kg for the smallest and the largest bed geometry and operating conditions considered in this study.

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In the present study, adsorbent bed of an adsorption chiller with finned flat-tube heat exchanger has been simulated three dimensionally based on the heat and mass transfer model with finite volume method. To examine the inter-particle mass transfer resistance effects on the system performance parameters, two different configurations of adsorbent bed including rectangular and trapezoidal fins with identical length and adsorbent mass have been considered and the effects of bed length on the system performance for different fin height and fin pitch have been studied. Moreover, effects of bed length for different particle diameters and also heating source temperatures have been investigated. Results indicated that increasing of bed length (or in the other words increasing of inter-particle resistance) increases and decreases cycle time and specific cooling power, respectively, yet the coefficient of performance is not influenced. Also, increasing bed length reduces the difference between specific cooling power of rectangular and trapezoidal beds if there is any. Moreover it is clear that optimum particles size increase with bed length increase. Finally, it is shown that effect of higher heating fluid temperature on specific cooling power improvement for beds with smaller length is more significant than those with longer length.

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Biochar and activated carbon, as carbon-rich porous materials, have wide environmental applications. In the present research, rice husk (RH) was used for preparation of biochar at 400, 600, and 800 °C under simple pyrolysis, physically-activated carbon with water steam, chemically-activated carbon with potassium hydroxide (KOH), and physiochemically-activated carbon with KOH and steam. Physical and chemical properties of biochar and activated carbons were characterized using nitrogen adsorption–desorption isotherm, Fourier transform, infra-red analysis, and Boehm method. The results showed that carbonization temperature and activation agents had significant effects on the characteristics of the samples. Activated carbon produced by KOH activation had the highest surface area (2201 m² g^-1) and total pore volume (0.96 cm³ g^-1). High concentration of sodium (Na) is an important limiting factor to reuse poor quality water resources in arid and semiarid regions. The sorption capacity of biochars and activated carbons was investigated by performing batch sorption experiments using Na as adsorbate. Na sorption was increased with increasing surface area and pore volume. The highest Na sorption capacity of 134.2 mg g^-1 was achieved by the KOH activated carbon, which has the highest surface area and pore volume. The kinetic data were well-fitted to pseudo-first order and intra-particle diffusion models.

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Data showed that by increasing the adsorbent dose, the availability of sorption sites eased resulting in greater percentage removal of the dye. The percent adsorption increased with increased contact time. Maximum quantitative removal of MB from an aqueous solution was obtained in 10 min for GFP contact time. The pH of an aqueous solution is an important factor in dye adsorption, as it affects the surface charge of the sorbent material and the degree of ionization of the dye molecule.The effect of pH on the amount of MB adsorbed onto fruit pulp was investigated over the pH range from 2 to 12. amount of dye adsorbed per unit mass of the adsorbent increased with increase in the initial concentration up to 25 mg/L. The When the of the solution was 2-6, the sorption of methylene blue was slightly weaker than at pH 6-12 due to poor dissociation of carboxyl Groups. The qe was found to increase with increasing pH. Optimal pH was determind 9. This can be on the basis of a decrease in competition between positively charged H and MB for surface sites and also by decrease in positive surface charge on the adsorbent, which results in a lower electrostatic repulsion between the surface and MB. SEM is one of the useful tools to examine the surface morphology of the biosorbent the SEM micrograph shows that the surface of GFP was porous.FTIR analysis showed that the main functional sites taking part in the sorption of MB included carboxyl and hydroxyl groups. Adsorption data are most commonly represented by the equilib-rium isotherm value, which is a plot of the quantity of the sorbate removed per unit sorbent (qeq) as the solid phase concentration of the sorbent against the concentration of the sorbate in the liq-uid phase (Ceq). The equilibrium isotherm value is of fundamental importance for the design and optimization of the adsorption sys-tem for the removal of a dye from an aqueous solution. Therefore, it is necessary to establish the most appropriate correlation for the equilibrium curve. Several isotherm models have been used to predict validity of the experimental data. The Langmuir isotherm is based on the assumption of monolayer adsorption on a structurally homogeneous adsorbent, where all the adsorption sites are identical and energetically equivalent, wherein the adsorption occurs at specific homogeneous sites within the adsorbent, and once a dye molecule occupies a site no further adsorption can take place at that site. The results indicate that the data for adsorption of dye (R2= 0/9738) fitted well with Langmuir isotherm. Studies suggest that GFP can be effectively used as a cost-effective adsorbent for removal of MB from aqueous solution. Batch adsorption studies show that removal is dependent upon process parameters like pH, sorbate and sorbent concentrations and contact time. The experimental equilibrium sorption data obtained from batch studies at optimized conditions fit well to Langmuir adsorption isotherm equation, indicating monolayer adsorption. FTIR analysis showed that the main functional sites taking part in the sorption of CV included carboxyl and hydroxyl groups. The number of experiments decreased of 256 to 64 by Taguchi method. Based on this that many textile industrial waste waters have an alkaline pH(8-12),this adsorbent can be used instead of effective compound. The present work shows that GFP is an efficient sorbents for the removal of methylene blue from aqueous solution and it may be an alternative to more costly sorbents such as activated carbon. The Taguchi method was efficient manner for optimizing process.

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Aflatoxins are potent carcinogenic and immunosuppressive agents. Acute exposure to high level of aflatoxins leads to aflatoxicosis, which cause rapid death due to liver failure. Immune modulating effects of probiotic bacteria have good prospects to detoxification of natural foods. This study was aimed to investigate the ability of Lactobacillus acidophilus strainLA-5 in the presence and absence of yoghurt starter culture for removing Aflatoxin M₁ (AFM₁) in comparison with yoghurt starter cultures (10⁸ CFU ml^-1). AFM₁ detoxification was evaluated for 21 days of yoghurt storage at 4°C at different concentrations of Aflatoxin (0.1, 0.5 and 0.75 µg L^-1). The amounts of unbound AFM₁ were determined using competitive Enzyme-Linked Immunosorbent Assay (ELISA). L. acidophilus combined with yoghurt starter culture and alone could significantly (P≤ 0.05) remove AFM₁ compared to control group. The results indicated that increasing initial AFM₁ concentration in the yoghurt samples and storage time affected the capacity of AFM₁ binding.

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In this study, the graphene oxide was used as adsorbent for the separation (adsorption and desorption) of flavonoids from lemon peel. Properties of desorption extract (total phenolic content, total flavonoid content, scavenging ability of DPPH free radicals) were determined. Antioxidant activity of desorption extract at three levels of 250, 500 and 1000 ppm and BHT synthetic antioxidant at 200 ppm in antioxidant-free frying oil were evaluated by measuring peroxide value, thiobarbituric acid test, conjugated DN and color index. Each gram of lemon peel extract contained 19767.20 μg phenolic compounds and 33.552 μg flavonoids on dry matter. Each gram of desorption extract contained 5861.56 μg phenolic compounds and 3.446 μg flavonoids on dry matter. Peroxide value, thiobarbituric acid, conjugated DN and color index of oil increased with increasing heating time and the highest increase was observed in the control treatment without antioxidants. Treatments containing desorption extract at 500 and 1000 ppm, can compete with BHT antioxidant. The results of this study indicated that desorption extract can be used as a replacement for synthetic antioxidants in oil.

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