The purpose of this study was the preparation, characterization and application of high-performance activated carbons (ACs) derived from oily sludge through chemical activation by KOH. The produced ACs were characterized using iodine number, N2 adsorption-desorption, Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The activated carbon prepared under optimum conditions showed a predominantly microporous structure with a BET surface area of 2263 m2 g−1, a total pore volume of 1.37 cm3 g−1 and a micro pore volume of 1.004 cm3 g−1. The kinetics and equilibrium adsorption data of phenol fitted well to the pseudo second order model (R2 = 0.99) and Freundlich isotherm (R2 = 0.99), respectively. The maximum adsorption capacity based on the Langmuir model (434 mg g−1) with a relatively fast adsorption rate (equilibrium time of 30 min) was achieved under an optimum pH value of 6.0. Thermodynamic parameters were negative and showed that adsorption of phenol onto the activated carbon was feasible, spontaneous and exothermic. Desorption of phenol from the adsorbent using 0.1 M NaOH was about 87.8% in the first adsorption/desorption cycle and did not decrease significantly after three cycles. Overall, the synthesized activated carbon from oily sludge could be a promising adsorbent for the removal of phenol from polluted water.

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Salinity and Zn deficiency in soils are two factors that may change the phytoavailability of Zn and Cd. The aim of this study was to determine the effects of salinity and Zn application on soil Cd and Zn solubility and their concentration in wheat shoots. A greenhouse experiment with wheat (Triticum aestivum L. cv. Rushan) consisting of two levels of Zn (0 and 15 mg Zn kg−1, in the form of ZnSO4), and five salinity levels of irrigation water (0, 60, 120, and 180 mM NaCl, and 120 mM NaNO3) in triplicate was conducted. Wheat was seeded in pots. After 45 d of growth, the shoots were harvested, and Zn and Cd concentrations were determined. After harvesting, electrical conductivity (EC), pH, and concentrations of anions and cations were determined in soil saturation extracts. Concentrations of Cd and Zn species in soil solution were predicted using the speciation program MINTEQA2. Increasing salinity increased total Cd (CdT), Cd2+, CdCl+, CdHCO3+, and CdCl20 concentrations in the soil solution, whereas no such effect was found for the NaNO3 treatment. Higher salinity decreased the total Zn (ZnT) and free Zn2+ concentrations in the soil solution and decreased Zn concentrations in the wheat shoots. With application of Zn fertilizer, shoot Cd concentrations decreased by 11 to 90%, whereas Zn concentration increased by 75 to 103%. Increasing salinity of irrigation water decreased shoot dry matter, especially if no ZnSO4 was applied. Application of Zn had a positive effect on salt tolerance of plant and increased dry matter of shoot.