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Background: Discharging high concentrations of nitrogen compounds in industrial effluent such as those from fertilizer manufacturing plants can cause various environmental problems like eutrophication. Objective: to investigate the efficacy of the granular activated carbon (GAC) and limestone (LS) as low cost media in removing ammonium ions from aqueous solution. Methods: Batch experiments were conducted to evaluate the efficacy of GAC and different ratios of GAC and LS mixture in the removal of ammoniacal nitrogen. The investigated parameters included contact time, initial ammonium ion concentration, pH, and amount of adsorbent. The adsorption isotherm and adsorption kinetic of ammonium ions by a mixture of GAC and limestone (LS) was studied Results: The experiments showed that the efficacy of GAC alone on the adsorption of NH4-N was 95% at shaking time 150 min, agitation speed 210rpm, temperature 22ºC and pH 9. The efficacy of a mixture ratio LS: GAC (30:20) on the removal of NH4-N was 75%. Conclusions: The study concluded that the removal percentage of ammoniacal nitrogen by a mixture of lime stone and GAC increase with the increase of agitation time and decrease with the increase of initial concentration while alkaline pH was more favorable for the adsorption of ammoniacal nitrogen.

Background: Phenol has been classified as hazardous pollutant and its presence in natural water is considered as a serious threat to human health and overall water quality. The major source of phenol pollution in the aquatic environment is wastewater from petroleum and petrochemical industries. Objective: This study aims to investigate the adsorption efficiency of granular activated carbon (GAC) and activated carbon prepared from rice husk (RHAC), a lowcost agricultural by product, in removing phenols from simulated wastewater. Methods: Batch adsorption studies were conducted to study the effect of various parameters such as initial concentration, agitation time, adsorbent dose and solution pH on phenol removal. Equilibrium data were analyzed by the Langmuir, Freundlich, Temkin and Hurkin-Jura. The adsorption kinetics were studied using the pseudo-first-order and second-order kinetics models. The mechanism of the adsorption process was determined from the intraparticle diffusion model. Results: The efficiency of GAC and RHAC on removal of phenol was 95% and 90% respectively at an agitation time of 6 hr, a pH 6,150 rpm, an adsorbent dose of 5 g/L, initial phenol concentration of 50 mg/L and a temperature of 20ºC. Acidic pH was more favorable for the removal of phenol. Increasing initial concentration of phenol decreases the percentage removal. The adsorption isotherm models fitted the data in the order: Freundlich > Langmuir > Tempkin isotherms. The pseudo-second-order kinetic model best described the adsorption process Conclusion: The results showed that the prepared activated carbon was an effective adsorbent for removal of phenol as a low-cost and an alternative adsorbent.

Low cost agricultural waste adsorbents can be viable alternatives to activated carbon for the treatment of contaminated wastewater. Sugarcane Bagasse, an abundant agriculture waste in Egypt, was used in the present study to prepare activated carbon. Batch adsorption experiments were conducted to study its effectiveness to remove cationic dye methylene blue from aqueous solution. The effects of initial dye concentrations, agitation time, solution pH and temperature on methylene blue dye removal were investigated. The optimum pH value for the maximum percentage removal of the dye was 7. Adsorption isotherms were determined and modeled with Redlich-Peterson, Langmuir and Freundlich equations at 20 °C. The kinetic data were analyzed using Pseudo-first order, pseudo-second order. The mechanism of the adsorption process was determined from the intraparticle diffusion model. Thermodynamic parameters such as standard enthalpy (ΔH°), standard entropy (ΔS°) and free energy (ΔG°) were determined. The equilibrium data were best fitted to the Redlich-Peterson isotherm model .The adsorption kinetics was found to follow the pseudo-second-order kinetic model with good correlation coefficient. The positive ΔH• value indicated that the adsorption process was endothermic in nature. The results revealed sugarcane bagasse activated carbon could be employed as a low-cost alternative adsorbent in wastewater treatment.