Iranian Journal of

Background and Objective: Application of chemical fertilizers in agricultural industry is known as one of the methods of crop enhancement. However, chemical fertilizers application can lead to an increased risk of chemical pollutants entering the human food cycle.  The aim of current research was feasibility study and evaluation of nickel from paddy soils in Lorestan province.
Materials and Methods: Sampling was done from 15 stations and randomly from rice cultivation areas in Silakhor plain of Lorestan province. Then, electrokinetic modification method was carried out in three reactors with lengths of 5, 10 and 15cm. After sample preparation, the initial and final concentration of nickel were measured and calculated using inductively coupled plasma - optical emission spectrometry (ICP-OES).
Results: The results showed that electrokinetic modification method was effective in reducing the concentration of heavy metals in agricultural soil samples and reduced the amount of nickel in soil to the permissible limits of the Iranian soil national standards (50 mg/kg). The initial values of nickel in paddy soil of composite samples were 108 mg/kg. Nickel maximum removal efficiency of 90.84% and 93.75% were observed in cathode and anode regions, respectively.
Conclusion: The health and quality of agricultural products depend on the use of safe soil within the limits of environmental standards. The results of this study showed that the EKR process is able to remove nickel from soil. As a result of the present process, nickel concentration has reached the permissible amount and even lower than the soil quality standard set by the Iranian Environmental Protection Agency.

Background and Objective: Mining is one of the important economic activities all over the world. It causes the release of various emissions, especially heavy metals in the soil, due to the weak exploitation and improper disposal of mineral wastes. Different techniques are used for soil remediation and heavy metal extraction; including the electrokinetic method (so effective in fine-grained soils). In this research, the electrokinetic process was used to extract copper from the waste of the mine in Birjand.
Materials and Methods: In this research, a 24 cm long PVC reactor was used. The retention time was 2, 4, and 6 days and the voltage gradient was 1 V/cm. Graphite electrodes and electrolyte solutions of nitric acid and citric acid were investigated for copper extraction. The electrode polarity was alternately changed in order to pH control and improve the extraction process.
Results: According to the results, the highest removal efficiency (54%) was obtained after 6 days using 0.1 M citric acid and distilled water in the anode and cathode reservoir, respectively. Further, by 24-hour polarity reversing, the copper removal efficiency increased to about 60%.
Conclusion: The use of citric acid in anode was more effective than nitric acid, leading to more copper removal. In addition, by periodically polarity change and keeping the soil pH in the neutral range, further dissolution of the metal and reducing its sedimentation in the soil occurred. As a result, the rate of its transfer outside the treatment area and removal efficiency increased.