Reza Zahiri

Assistant Professor of Applied Geology

Selected Publications

Hashemi, K.H., Zahiri, R., Hashemi-Moghaddam, H. Removal of Cr6+ and Pb2+ from Aqueous Solutions by Natural Zeo-Bentonite (2013) Asian Journal of Chemistry, 25 (16), pp. 9138-9140.

DOI: 10.14233/ajchem.2013.15053A

In this study the ability of zeo-bentonite (zeolite-bentonite) to remove Cr(VI) and Pb(II) ions from water resources has been studied. The analysis conducted on the use zeo-bentonite shows that illite, montmorillonite and clinoptilolite are the most important minerals in the zeo-bentonites. The effect of various parameters such as initial concentration of the metal, pH solution, contact time and temperature in is considered. Results showed that, in the initial volume of 100 mL of solution and initial concentration of 0.005 mol/L, 1 g of adsorbent amount and temperature of 100°C, absorption of chromium 6 in pH = 5 and pH = 3 in lead 2 absorption maximum is adsorption process for both the metal is very good and very good zeo-bentonite as absorbent to absorb these metals are considered.

AUTHOR KEYWORDS: Adsorption; Cr6+; Pb2+; Zeo-bentonite

Hashemi, K.H., Zahiri, R., Ebadi, A.G. Removal of Ni2+ and Cd2+ from aqueous solution using Iranian natural Bentonite (2013) Asian Journal of Chemistry, 25 (16), pp. 9141-9143.

DOI: 10.14233/ajchem.2013.15053B

Bentonites consist clay minerals of the smectite group have a wide range of industrial uses. A particular feature of this group of minerals is the substitution of Si4+ and Al3+ in the crystal structure by lower valency cations. The structure, chemical composition, exchangeable ion type and small crystal size of smectite are responsible for several unique properties. In this study by using chemical analysis analysis methods e.g.; XRD, XRF, SEM, the kind of Reshm natural bentonite mine have been determined as montmorillonite and clinoptilolite. Then the ability of bentonite to reomove heavy metal ions from wastewater and its factors affecting it have been examined. The batch sorption experiments of Ni2+ and Cd2+ were conducted on Na-bentonite under various conditions. Adsorption behaviour of bentonite was strongly depending on pH, initial concentration, time and temperature. The removal rate of bentonite decreases with an increase in the initial metal ion concentration. pH for removal of Ni2+ is 4 and for Cd2+ is 5.

AUTHOR KEYWORDS: Adsorption; Batch exprimetall; Bentonite; Ni2+Cd 2+; Wastewater

Mostaghelchi, M., Zahiri, R., Miremad, S.H., Ebadi, A.G. Use of mica mineral powder in bricks industry to improve the performances (2013) Asian Journal of Chemistry, 25 (16), pp. 9144-9148.

DOI: 10.14233/ajchem.2013.15053C

In this work, the usability of mica mineral powder as an additive material in industrial brick were investigated. Mica mineral was acquired from an inactive mica mine which is located at the south of Shahrod, Semnan, Iran and industrial brick mortar was obtained from a brick company in Damghan. Mica mineral and brick mortar were prepared for various processes of industrial brick investigation. Mica mineral were powdered and this powder in different proportions was mixed with industrial brick mortar, starting amount of 0 wt % up to 15 wt % in 54-10 mm bar shape. Bars for testing of physico-mechanical properties of the samples having different mica mineral powder composition. These prepared bars were uniaxially pressed and sintered at the 1100°C during 1 h. It was found that the amount of mica mineral additive had positive effect on the physical, chemical and mechanical strength of the produced industrial brick. With increasing demands of the construction industry, bricks quality and cost become more important day by day in Iran. In addition, the usage of mica mineral powder for the production of industrial bricks has significant important role on reacting the local mica mine and local jobs for populace along with a great contributions to economy and ecology of the country. In this study, the efficiency of mica powder additives to produce better bricks was suggested.

AUTHOR KEYWORDS: Additive; Bricks; Building material; Clay; Fired bricks; Mica mineral

Kalhor, D., Zahiri, R., Ketabi, S.A., Ebrahimzad, A. The effect of Ag intermediate layer on crystalline, optical and electrical properties of nano-structured thin film (2010) Indian Journal of Physics, 84 (5), pp. 539-

ITO thin films and ITO/Ag/ITO multilayered films were prepared on glass substrate by reactive thermal evaporation technique without intentionally heating the substrate. After deposition the films were annealed in air at three different temperatures (300°C, 420°C and 540°C). The thickness of each layer in the ITO/Ag/ITO films was kept constant at 50 nm/10 nm/40 nm. The opto-electrical and structural properties of ITO/Ag/ITO multilayered films were compared with conventional ITO single-layer films. Although both films had identical thickness, 100 nm, the ITO/Ag/ITO films showed a lower resistivity. XRD spectra showed that Ag intermediate layer had a small effect on crystalline properties of ITO/Ag/ITO films. © 2010 IACS.

AUTHOR KEYWORDS: Annealing; Indium-tin-oxide; Multilayered films; Thermal evaporation