---

Research subject: In this study, EDTA-functionalized Fe₃O₄@SiO₂ magnetic nanocomposites with core-shell structure were synthesized to remove divalent cadmium ions from aqueous solutions.
Research approach: During the first step, Fe₃O₄@SiO₂ nanosphere core-shell is synthesized using nano Fe₃O₄ as the core, TEOS as the silica source and PVA as the surfactant. This strategy relies on the covalently bonding of ethylendiaminetetraacetic acid to bis(3-aminopropyl)amine and cyanuric chloride functionalized magnetic nanoparticles. In the next step, characteristics of surface functional groups, crystal structure, magnetic properties, size and surface morphology of these nanoparticles were investigated, identified and analyzed using physico-chemical characterization techniques including fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), dynamic light scattering (DLS), vibration sample magnetometry (VSM) and Brunauer-Emmett-Teller (BET) surface area analyzer.  The adsorbent, due to its magnetic property, could be simply separated from the reaction mixture by a permanent magnet and reused in five consecutive cycles without considerable loss in its activity.
Main results: To probe the nature of the adsorbent, various experiments were investigated like adsorbent dose and contact time were optimized. Kinetic studies and the effect of different amounts of adsorbent to remove divalent cadmium ions from aqueous solutions show a maximum adsorption of 94% at ambient temperature. Moreover, the recyclability of Fe₃O₄@SiO₂-EDTA was investigated in order to remove the divalent cation for successive adsorption-desorption cycles. All the results of studies show that the synthetic nanocomposite Fe₃O₄@SiO₂-EDTA is an effective, recyclable adsorbent with excellent performance for the removal of divalent cadmium.

---

  The influence of different levels of NaFeEDTA compound on the physicochemical and sensory properties of Petit Beurre biscuit was evaluated. NaFeEDTA was added to biscuit formulation in levels of 576, 720, 864, 1008 and 1152 mg/kg so that 100 gram of fortified biscuits to be contained 7.2, 9, 10.8, 12.6 and 14.4 mg iron/100 g respectively. Fortified biscuits were stored in polyethylene pouches for 60 days under ambient temperature condition (17-20°c) and far from light. Fortification with NaFeEDTA had not significant effect on pH, moisture and ash content of fortified comparing to the control. The data measured an Atomic Absorption instrument showed that iron content was significantly different between the fortified and control samples (P<0.05). The percent of iron loss for fortified samples ranged between 2.63%, 0.33%, 0.64%, 2.53% and 1.18% respectively. The peroxide value was increased in all samples during a 60-day storage period; however this increase was higher in the fortified biscuits as compared to control especially after 28 days. NaFeEDTA compound at different levels had not significant effect on breaking strength of fortified biscuits. Sensory evaluations were showed that the addition of NaFeEDTA to the biscuit formula have significant effect (P<0.05) on the color, texture, and flavor of fortified biscuits. With regard to the results and also the use of NaFeEDTA in the proposed fortification range (10 mg iron, 67 mg EDTA/person per day), 720 mg/kg (9 mg iron/100 g) level of NaFeEDTA as an optimum level for biscuit fortification was suggested.

---

The remediation of heavy metal contaminated soils is one of the known challenges of researches in many industrial countries. The use of EDTA (Na2EDTA.2H2O) is one of the common soil-washing methods. In spite of several research conducted on this subject, the optimization of the use of EDTA for heavy metal removal from contaminated soils, specifically soils with relatively high surface area, are not well addressed in the literature.  The main objective of this research is to evaluate the optimization of the use of EDTA in remediation of Pb-contaminated bentonite. To achieve the above mentioned objective, bentonite samples were laboratory contaminated with different concentrations of lead nitrate. Lead nitrate at concentrations of 0.001, 0.005, 0.01, 0.5 and 0.7 mol/l (1, 5, 10, 50 and 70 cmol/kg-soil) was used to laboratory contaminate bentonite. After drying the contaminated samples, they were exposed to different concentrations of EDTA. EDTA at concentrations of 0.001, 0.005, 0.01, 0.05, and 0.1 mol/l (1, 5, 10, 50, and 100 cmol/kg-soil) was used in 1:10 soil:electrolyte ratio in accordance to EPA. For sample preparation, 20 ml of EDTA at the required concentration was added to 2 grams of a dried contaminated bentonite. Samples were shaken for 2 hours on a horizontal shaker. Then, they were kept for 96 hours to reach equilibrium. In these 96 hours of equilibrium, soil samples in centrifuge tubes were shaken 2 hours in each 24 hours. Finally, samples were centrifuged with 4000 rpm to separate the solid and electrolyte. Then, the efficiency of Pb removal from samples was measured by analyzing the electrolyte. It should be emphasized that to prevent precipitation of lead ions in electrolyte, nitric acid was added to electrolyte to keep the pH less than 2. The achieved results show that the quantity of removed Pb ions by the application of EDTA is relatively equal to the concentration of applied EDTA. In other words, as the 1 , the quantity of lead removal by EDTA is equal to EDTA concentration. This quantity of lead removal is neither a function of lead concentration nor to the number of soil washing by EDTA. In addition, since the quantity of removed Pb is only a function of EDTA/Pb ratio, therefore such a removal is not dependent to the pH variations caused by different concentrations of Pb or EDTA. This approves that the high buffering capacity of bentonite in comparison to other variables of environment has the minimum impact on the interaction process of EDTA and heavy metal contaminated bentonite.

---

In the production of fuel briquettes, different additives are used in order to improve the technical parameters. In the present study, two types of lignocellulosic binders including nanocellulose and lignin have been used. Due to the different chemical structure and difference in calorific value of each of these two materials (lignin and nanocellulose) and the difference in their mechanism of action on improving the thermal properties of fuel briquettes, in order to evaluate the final product of thermal analysis using calorific value and TGA and DTA diagrams were used. The results show the positive effects of the use of cellulosic binders in improving the thermal behavior of biofuel briquettes. Thermal analysis showed that 9% nanocellulose and 9% lignin treatments with 19.85 MJ / Kg and 25.75 MJ / Kg had the highest calorific value compared to the control sample, respectively. The diagram obtained from thermal analysis (TGA) of the control sample and the samples treated with lignin and nanocellulose show that the treated samples have lower weight loss rate, higher burning rate and higher burning temperature.

---

The toxic effects of chromium in plants, animals and human beings in the environment have been widely studied. In the present study, pot experiment was conducted to determine the effects of chromium on photosynthetic pigments, Nitrate Reductase (NR) activity and total amino acid, proline, total protein and leghaemoglobin content of Sesbania grandiflora (L.) Pers. The seedlings were treated with Chromium Cr (VI), concentrations ranging from 0.38-1.92 mM Kg^-1 of soil with 0.35 mM Ethylene Diamine Tetra Acetic acid (EDTA) and without EDTA. The efficacy of EDTA in its presence and absence was compared for periods of 30, 60 and 90 days. Our results in comparison with our control indicate the inhibitory effect of chromium to S.grandiflora. From the results it has been observed that, increasing concentrations of chromium in the presence of EDTA showed a significant increase in proline and total amino acid contents, while the total chlorophyll, leghaemoglobin content and total protein content decreased and the NR activity of the plant was also affected greatly.

---

Electrokinetic (EK) remediation is a very effective option for the soil decontamination; however, its efficiency depends on several factors. In the present study, the ability of Ethylene-diaminete-traacetic-acid (EDTA) and pulse current to improve this method for treating fine-grained soils containing heavy metals (HMs) was investigated. In so doing, first, the studied sample (mainly kaolinite) was mixed with a concentration of 5000 mg/kg zinc (Zn) and lead (Pb) and then subjected to an electrokinetic test with voltage gradient of 2 V(DC)/cm² (in the form of continuous current and pulse) under 7, 14 and 28 days. The pulse current used was ON for 30 minutes and OFF for 10 minutes. In this process, different concentrations of EDTA (including a concentration of 0.1 M and 0.2 M) were also added to the anode and cathode reservoirs, separately and simultaneously. The obtained results showed that in the conditions of continuous current and without EDTA addtion (the common EK method), the EK removal efficiency, especially for lead, was not noticeable. According to the changes in the microstructure of soil sample and its electrical conductivity (EC) between the anode and the cathode electrodes, the reason can be ascribed to the decrease in current density due to precipitation of pollutants in the soil matrix and decresing the HMs transportation in the cathode side, as clearly confirmed by the XRD patterns and EC tests. In this case, increasing the test time from 7 to 28 days (despite more energy consumption) mainly caused the change of the pollution position in the around of anode side and the HMs removal in the cathode side is not enhanced, indicating that there is a limited effect (about 20%) on the total efficiency of the EK tests. It was found that the addition of EDTA only in the form of catholyte solution, even with the equivalent concentration of soil pollution, has a low effect on improving the electrokinetic response. On the other hand, the presence of the chelating agent in both reservoirs of the EK device, especially by applying the pulse current (with a frequency equal to 36 cycles/day) accelerates the treating process of EK remediation. In fact, as the results of macro-structural tests, scanning electron microscope (SEM) images and X-ray diffraction (XRD) analyses indicated, such improvement can be attributed to two major changes in soil-pollutant interaction. First of all, the presented EK method, by developing the penetration of the acid front towards the cathode side and limiting the polarization ability of clay particles, causes the formation of flocculation and reduces the soil ability to keep pollutants. Also, this system greatly reduces the contribution of insoluble phases through the processes of redissolution and formation of the stable complexes as well as generates a disturbance in the initial formation of metal precipitation due to the reduction in the hydrolysis reaction of the cathode part. Synergy of these changes has an prominent role in accelerating the EK mechanisms; so that compared to the conventional EK model, while reducing energy consumption by 25%, it can also increase the removal efficiency by nearly 2.6 times.
 

---