Sürdürülebilir Kalkınma Amaçları
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- MakaleYalnız künye2015Scopus SJRQ2Removal of Phosphate from Aqueous Solutions by Chemical- and Thermal-Modified Bentonite Clay
Tanyol, Mehtap; Yonten, Vahap; Demir, Veysel
The study investigated phosphate adsorption from aqueous solutions using chemical- and thermal-modified bentonite in batch system. The adsorbent was characterized by SEM, BET, and FTIR spectroscopy. Contact time, beginning phosphate concentration, pH of the solution, and the effects of the temperature on phosphate adsorption capacity were determined by a series of experimental studies. In a wide pH range (3-10), high phosphate removal yields were obtained (between 94.23 and 92.26 %), and with the increase in temperature (from 25 to 45 degrees C), phosphate removal increased. Langmuir and Freundlich isotherms were used to determine the sorption equilibrium, and the results demonstrated that equilibriumdata displayed better adjustment to Langmuir isotherm than the Freundlich isotherm. Phosphate sorption capacity, calculated using Langmuir equation, is 20.37 mg g(-1) at 45 degrees C temperature and pH 3. Mass transfer and kinetic models were applied to empirical findings to determine the mechanism of adsorption and the potential steps that control the reaction rate. Both external mass transfer and intra-particle diffusion played a significant role on the adsorption mechanism of phosphate, and adsorption kinetics followed the pseudo-second-order-type kinetic. Furthermore, thermodynamic parameters (Delta H degrees, Delta G degrees, Delta S degrees) which reveal that phosphate adsorption occur spontaneously and in endothermic nature were determined. The results of this study support that bentonite, which is found abundant in nature and modified as an inexpensive and effective adsorbent, could be used for phosphate removal from aqueous solutions.
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İncele - MakaleAçık Erişim2013Scopus SJRQ4Column Studies on Effect of Phosphate Immobilization on Removal of Metals from Stormwater Runoff in Bioretention Cell
Demir, V.; Bin-Shafique, S.
Batch studies indicated that low cost native materials such as loam soil, juniper mulch, hardwood mulch, pine mulch and sawdust performed efficiently as media in bioretention cell for removal of copper and lead from stormwater runoff. Juniper mulch performed best in batch studies was used in column studies. Column studies suggested that the presence of phosphate has a pronounced effect on metal immobilization. This is due to the formation of metal phosphates that have extremely low solubility. The remaining metals were adsorbed on bioretention media of the bioretention cell. Breakthrough adsorption and desorption curves for lead and copper were measured in presence and absence of phosphate immobilization. Copper reached a breakthrough curve in around 20 days and lead in 30 days. Column studies showed that in all samples addition of phosphate also decreased the leaching of lead and copper back to aqueous solution consistent with lead and copper immobilization.
AtıfWoS3OpenAlex3İncele