Iranian Journal of

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MicrosoftInternetExplorer4 Background and Objectives: Existence of Heavy metals in water resources is one of the most important environmental problems in many countries. These metals have dangerous effects on human health. The purpose of this study is  to investigate and compare lead removal by nanometer and millimeter absorbents of Zizyphus Spinachristi fly ash.
Materials and Methods: This study was non-continuous experiment which was implemented under laboratory conditions with and by changing effective factors such as pH (3, 4, 5, 6, 7, 8), contact time (5, 10, 15, 30, 45, 60, 90, 120 minutes) and adsorbent concentration (1, 2, 5, 10, 20 and 50 mg/ L). The data was fitted based on four models including Ho et al, Lagergern, Lungmuir and Freundlich which the first two models used for absorption kinetic and the latter two considered as absorption isotherm.
Results: The Result of this study showed that as the pH increases from 3 to 5 adsorption efficiency increased as well. Furthermore, when pH was over 5, the metal ions settled down. With increasing contact time, adsorption efficiency increased as well. With increasing the amount of nanometer as an adsorbent, removal efficiency increased and then decreased. Also the adsorption process followed precisely Ho et al kinetic and Langmuir isotherm, for both absorbents.
Conclusion: Based on the obtained results, specific area of the nano particles was more than millimeter particles (29.56 m2/g & 17.80 m2/g), therefore adsorption capacity of nano absorbent was four times more than adsorption capacity of millimeter (19.93 mg/g & 17.80 mgr/g). Furthermore, the findings concluded high capability of nano particles towards Sorption of lead ions (Pb) from aqueous solutions.

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MicrosoftInternetExplorer4 Background and Objectives: The increasing demand for drinking water has led scientists to the use of saline waters, but existing desalinating processes are very expensive. carbon aerogel is a type of organic aerogel that is suitable for desalination owing to its unique porous structure. Low potential of fouling and deposits, very low wastewater production, electrostatic regeneration of aerogels and, in turn, no need to acid consumption, and lower power consumption are some of this technology benefits.
Materials and Method: In this experimental- analytical study, the purpose was survey of saline and brackish water desalination using carbon aerogel technology and its comparison with electrolysis.The community studied was synthetic salt water samples, using of TDS and EC indicators. The minimum synthetic samples were 243. In this regard, after polymerization of Resorsinol and Formaldehyde compounds under ambient pressure conditions and then its pyrolysis, we fabricated plates of carbon aerogel.
Result: With manufacturing in the pilot-scale, the effect of different parameters, including input salt concentration, current, water flow, distance of between electrodes and pH, on NaCl sorption amount of carbon aerogel electrodes were studied. Generally, adsorption amount increased with increasing of current and NaCl concentration and decreased with increasing of distance electrodes, flow and pH. 
Results: Fabricating reactor at pilot-scale, we studied the effect of different parameters, including input salt concentration, current, water flow, intra-distance of electrodes, and pH on the NaCl sorption using carbon aerogel electrodes. Generally, adsorption capacity increased with increasing of current and NaCl concentration in the inlet flow, and it decreased with increasing intra-distance of electrodes, flow, and pH.
Conclusion: Under the most optimal conditions, our results showed that the NaCl adsorption rate on carbon aerogel electrodes was about 1.43×10^-4 M NaCl per g of carbon aerogels indicating its cost-effectiveness.

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