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The present work deals with the equilibrium adsorption of Hg(II) onto carbonized Rosmarinus officinalis leaves (ACROL) as a new adsorbent from aqueous solution and it has been investigated. ACROL samples were prepared by physical carbonization at 773 K for 1 h. Titration method was used to determine the concentration of Hg(II) before and after adsorption onto ACROL by ethylenediaminetetraacetic acid, EDTA, as chelating agent. Batch equilibrium studies were carried out under different experimental conditions such as Hg(II) concentration and temperature. The relationship between the amount of Hg(II) onto ACROL can be described using four tow-parameter isotherm models. The equilibrium sorption data were analyzed using Freundlich, Langmuir, Dubinin-Ra-dushkevich (DRK) and Temkin isotherms. The experimental results were found to fit the Langmuir isotherm model with a monolayer adsorption capacity of 588.2 mg/g at 318 K, while they were found to fit the Freundlich isotherm model at 298 K. The KL was decreased with increasing temperature, indicating a bond strength between Hg(II) and ACROL decreased with increasing temperature and sorption is exothermic. From DRK isotherm, free energy, E, was higher than 31 kJ/mol suggesting the Hg(II) adsorption onto ACROL chemical sorption. The thermodynamic studies revealed that the process is spontaneous nature of Hg(II) adsorption by ACROL and exothermic. The findings from this research show that ACROL has capability to remove Hg(II) from aqueous solutions.

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IndexTerms-Activated carbon, date stone, physical-chemical properties.

Abstract-In this research, palm kernel powder (PKP) was utilized as a bioadsorbent for the removal of Cr(VI) and Cu(II) ions from aqueous solutions. Batch studies were preformed to evaluate the effect of various experimental parameters on Cr(VI) and Cu(II) adsorption onto PKP. The adsorption equilibrium was reached after 70 min. The adsorption capacity of Cr(VI) and Cu(II) was pH-dependent showing a maximum at equilibrium pH 2 and 5, respectively. The percentage removal of heavy metals by PKP varied in order unmodified adsorbents>HNO3>H3PO4. The adsorption isotherm and kinetics of Cr(VI) and Cu(II) were also investigated using Langmuir and Freundlich adsorption isotherm models and pseudo-first order (LSO) and pseudo-second-order (PSO) kinetic models. The data was better described by Freundlich adsorption isotherm model and PSO kinetics in the concentration range studied. For environmental study, it was found that the adsorption capacity for heavy metals decreased in the raw waste water sample in comparison with the synthetic waste water system.