Shahid Beheshti University of Medical Sciences and Health Services

About: Shahid Beheshti University of Medical Sciences and Health Services is a education organization based out in Tehran, Iran. It is known for research contribution in the topics: Population & Medicine. The organization has 19456 authors who have published 33659 publications receiving 365676 citations.

Application of response surface method for coagulation process in leachate treatment as pretreatment for Fenton process: Biodegradability improvement

Abstract: Landfill leachate is a complex mixture containing toxic and recalcitrant substances with considerably low BOD 5 /COD indicating the necessity and difficulty of its treatment. Amongst treatment processes, integrated separating-destructive processes are promising ones. In this way, suspended and colloidal particles get separated in a separating process while the soluble fraction undergoes a destructive process; probably an advanced oxidation process. In the present study, coagulation process using ferric chloride was employed as a pre-treatment process for landfill leachate. Design of experiment, modeling and data analysis were conducted using response surface method (RSM) considering COD, color and TSS removals as responses. In optimum conditions (pH = 7 and 1500 mg/L FeCl 3 ) the average COD, color and TSS removals were approximately 65%, 79% and 95%, respectively. Afterwards, Fenton process was applied for degradation of the leachate. Average oxidation state (AOS) and BOD 5 /COD values increased from −0.51 and 0.11 to +1.7 and 0.4 respectively. Phyto-toxicity test was also conducted based on the germination index which was dramatically increased after coagulation and Fenton processes.

Active corrosion protection of Mg-Al-PO 4 3− LDH nanoparticle in silane primer coated with epoxy on mild steel

Abstract: Mg-Al-PO 4 3− layered double hydroxide (LDH) nanoparticle was synthesized through an anion exchange method and characterized by XRD, IR spectroscopy and SEM. The phosphate and Mg 2+ release ability of Mg-Al-PO 4 3− LDH in the 3.5 wt. % NaCl solution was measured by inductively coupled plasma-optical emission spectrometer (ICP-OES). Results showed the release of Mg 2+ from the LDH scaffold along with phosphate anion from LDH gallery, illustrating importance of solubility rather than ion-exchange mechanism. Then, the corrosion inhibitive behavior of Mg-Al-PO 4 3− LDH in 3.5 wt. % NaCl solution was assessed by electrochemical measurements and FE-SEM in comparison with the Mg-Al-NO 3 − LDH. The results showed that Mg-Al-PO 4 3− LDH forms inhibitive film on the mild steel and significantly mitigate corrosion compared to Mg-Al-NO 3 − LDH. The LDHs were also employed in a silane primer top-coated by epoxy-polyamide on mild steel. The results of electrochemical measurements showed significant active corrosion protection ability of Mg-Al-PO 4 3− LDH in the coating with an artificial defect. Furthermore, the adhesion strength of the coating including Mg-Al-PO 4 3− LDH to mild steel after exposure to salt spray (5% NaCl solution) was improved.