Effect of citrus peel and time on the immobilization of nickel and zinc in contaminated soil
Subject Areas : Journal of Plant Ecophysiologyبهاره لرستانی 1 , مهرداد چراغی 2 , هاجر مریخ پور 3
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Abstract :
Investigating and identifying soil contaminants soil are essential. A wide range of techniques are available for the removal of metal ions from polluted environments. Each of them has advantages and disadvantages based on simplicity, flexibility, efficiency of processes, cost, technical and maintenance problems. Therefore, easy, effective, economical and environmentally friendly techniques for treatments are needed. Use of organic absorbents is one of the newest and most appropriate cost techniques. In this study, soil was treated with citrus peel as low cost organic immobilizers in order to investigate the time effect on decreasing mobility of Ni and Zn. The soil was artificially contaminated with Ni and Zn in separate containers. Both elements were incorporated at a dose of 600 mg l-1 and then citrus peel was added to soils at the rate of 5%. Sampling of treatments was in 1h, 1, 3, 7, 14, 21, 28 days of incubation. The experiment was done with 2 treatments including polluted soil samples with and without citrus peel as control in completely randomized design. Statistical analysis done using the SAS software (version 9.1) and Duncan test was performed at 5% level. Results indicated that at the first time of incubation, the pH of soils decreased due to the presence of citrus peel and increased the availability of metals. But the prolonged incubation time led to increasing metal adsorption onto organic adsorbent surfaces and decreasing the metal concentration in exchangeable fraction. Mean Zn concentrations in the control soil and soil treated with citrus peel, were 107.8 and 98.3 mg kg-1 and mean Ni concentrations were 144.5 and 134.4 mg kg,-1 respectively. Differences in control and the citrus peel treatment for both elements were significant.
