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Response surface methodology (RSM) and its application for optimization of ammonium ions removal from aqueous solutions by pumice as a natural and low cost adsorbent

100%

Moradi M. , Fazlzadehdavil M. , Pirsaheb M. , Mansouri Y. , Khosravi T. , Sharafi K.

tom Vol. 42, no. 2

33--43

This research was conducted to study the adsorption of ammonium ions onto pumice as a natural and low-cost adsorbent. The physico-chemical properties of the pumice granular were characterized by X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Modeling and optimization of a NH4+ sorption process was accomplished by varying four independent parameters (pumice dosage, initial ammonium ion concentration, mixing rate and contact time) using a central composite design (CCD) under response surface methodology (RSM). The optimum conditions for maximum removal of NH4+ (70.3%) were found to be 100 g, 20 mg/l, 300 rpm and 180 min, for pumice dosage, initial NH4+ ion concentration, mixing rate and contact time. It was found that the NH4+ adsorption on the pumice granular was dependent on adsorbent dosage and initial ammonium ion concentration. NH4+ was increased due to decrease the initial concentration of NH4 and increase the contact time, mixing rate and amount of adsorbent.

Application of advanced oxidation process (H2O2/UV) for removal of organic materials from pharmaceutical industry effluent

84%

Azizi E. , Fazlzadeh M. , Ghayebzadeh M. , Hemati L. , Beikmohammadi M. , Ghaffari H. R. , Zakeri H. R. , Sharafi K.

tom Vol. 43, nr 1

183--191

Pharmaceutical wastewater is one of the major complex and toxic industrial effluents containing little or no biodegradable organic matters. In this study, H2O2/UV based advanced oxidation process (AOP) was used to remove organic materials from pharmaceutical industry effluent. For the chemical oxygen demand (COD) removal radiation of medium pressure mercury vapor UV lamp was used in the presence of hydrogen peroxide (H2O2/UV). Results indicated that the efficiency of COD removal depends on the initial concentration H2O2, oxidation time and pH. The efficiency of COD removal at low H2O2con-centration was very low even coupled with UV light, which can be attributed to the low generation of hydroxyl radicals (OH). At high concentration of H2O2 (500 mg/dm3) and optimum pH (pH = 4), 87.6% removal efficiency could be achieved during 70 min oxidation. For high concentration of H2O2 (500 mg/dm3) at pH 3 and 7, the maximum COD removal efficiency was 28.5% and 15.2% respectively, indicating significant roles of pH and H2O2concentration in the process of COD removal.