Cobalt contamination in wastewater from industries has been increased in many countries including Egypt. Adsorption is the most progressively for heavy metals, removing from wastewater by using agricultural waste and by-products such as rice straw. Unmodified and modified rice straw has been evaluated as their ability to bind with metal ions. In this study, four characterizations of raw rice straw have been conducted. The morphological characteristics by SEM, EDXA, and the functional group present in the rice straw by FTIR spectroscopy and the XRD technique. Rice straw contains about AOH functional group that can bind with metal ions. To be able to enhance the sorption capacity of rice straw in metals, removing from waste water, alkali treatment should be done. This shows that rice straw can be used as adsorbent for removing cobalt ions from wastewater. The effect of pH, amount of adsorbent, different concentrations of cobalt, sorption kinetics and isotherms were studied in batch experiments. The good correlation coefficient was obtained from pseudo second-order kinetic model, which agreed with conception as the ratelimiting mechanism. Sorption isotherm test showed that equilibrium sorption data were better represented by Langmuir model than the Freundlich model. The thermodynamic parameters such as DH, DS, DG and E a are also calculated.

T HE MORINGA oleifera seed (MOS) was characterized by pHzpc, Fourier transform infrared spectroscopy (FT-IR), X-ray and scanning electron microscopy (SEM) in order to get an insight of the surface charge, functional groups, and morphology of the biosorbent, respectively. The MOS studies were conducted on Cd (II) with different parameters, such as solution pH, contact time, initial concentration of the pollutant and temperature were examined. Experimental results revealed an increase of the removal percentage of Cd (II) using coagulation compared with adsorption technique with increases of the initial Cd (II) concentration, contact time, pHs and temperatures. The Freundlich isotherm linear equation is better described for the adsorption process and coagulation process for the removal of Cd (II) ions. By Comparing the thermodynamic parameters of Cd (II) removal, such as ∆H, ∆S and ∆G, distinct behaviours were observed, where adsorption process is positive values along all temperatures while coagulation process showed negative values. According to S* value, the adsorbent system is very high while the coagulation system is very low.

This work demonstrates the potential of Moringa oleifera seeds powder as an adsorbent for the removal of heavy metals from wastewater. The moringa oleifera seeds powder is characterized as an adsorbent for the removal of heavy metals from wastewater using FTIR, XRD, pH pzc , SEM and BET techniques. Several processing parameters such as; contact time, adsorbent dose, initial lead ion concentrations, pH, and temperature are optimized. The equilibrium data for bio-sorption are analyzed by using Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models to define the best correlation for lead ions. Among the four isotherm models, both Temkin and Freundlich models best describe the experimental data for Pb(II).The adsorption of the metal ions, Pb (II) is well defined by the pseudo-second order model (R 2 > 0.99). The interaction of the cationic species with the MOS powder is predominately via chemisorption rather than physisorption. The thermodynamic parameters such as ΔS, ΔH and ΔG are also determined.

In this study, Magnetite-hydroxyapatite nanocomposites were prepared by in situ precipitation of the calcium phosphate phase in an iron oxide colloidal suspension. Adsorption of cobalt was initially rapid and the adsorption process reached a steady state after 180 min. The Co(II) adsorption capability of the MHAp was investigated as a function of temperature, pH, ionic strength, adsorbent dosage, agitation speed and initial Co(II) concentration. Theincrease in pH and temperature resulted in an increase in Co(II) adsorption capacity; Increasing ionic strength increased the adsorption of Co(II) by MHAp; The adsorption isotherms were well described by the Freundlich model, Langmuir, Temkin and D-R models. The Freundlich model was found to provide the better fit with the experimental data. Different types of adsorption kinetic models were used to describe the Co (II) adsorption behaviour, and the experimental results fitted the pseudo-second-order kinetic models well. Thermodynamics parameters such as ∆H o , ∆S o , ∆G o revealed that the adsorption of Co(II) by MHAp was endothermic in nature, physisorption, spontaneous at 308 and 318K.

The present study aims to synthesize an activated carbon adsorbent (S-AC, P-AC and OH-AC) from polystyrene divinyl benzene waste under different carbonization temperature (450 o C and 900 o C and activation conditions (H2SO4, H3PO4 or NaOH). It being characterized and applied as an adsorbent for manganese removal from groundwater. FTIR results indicate that the changes in the peak intensities clear that the binding process was occurring on the surface of the adsorbent. Different factors such as solution pH, adsorbent dosage, contact time, temperature and Mn(II) initial concentration were investigated. The results showed that manganese adsorption capacity decreases with the increase of the carbonization temperature (900 o C) and of activating agent H2SO4 > H3PO4 >NaOH. Kinetically, it was shown that the activation temperature of 450 o C is the best temperature for activating the adsorbent carbons. The pseudo-first-order model is appropriate for predicting the adsorption process of Mn(II) onto the P-AC 450 o C, P-AC 900 o C and OH-AC 900 o C, while the pseudo-secondorder model is appropriate for predicting the adsorption process of Mn(II) onto the both S-AC 450 o C, S-AC 900 o C, OH-AC 450 o Cand OH-AC 900 o C. Thermodynamic calculations affirmed that Mn(II) adsorption onto S-AC and P-AC was an endothermic process while onto OH-AC was exothermic process. Finally, the results suggested that the prepared S-AC has high adsorption capacities for Mn(II) compared with other adsorbents, such as P-AC and OH-AC. Therefore, S-AC 450 o Ccan be used in the groundwater treatment unit.

In this study, the adsorptive capacity of the synthetic Indion 225Na cation exchange resin was evaluated for the removal of different ions species from Oil Refining Company wastewater. Batch studies were performed to evaluate the effects of various experimental parameters by such as pH, contact time, temperature, resin and initial concentrations on the removal ion species. The Indion resin was characterized using FT-IR spectroscopy and scanning electron microscopy were used to analyse the resin. The adsorption kinetics were fitted by the pseudo-first-order, pseudo-second-order kinetic equations and intra-particle diffusion model. The thermodynamic parameters, sticking probability and activation energy of the removal processes were also evaluated. Based on these results, the synthetic Indion 225Na resin could be applied for treatment of industrial effluents which are rich in inorganic pollutants.

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