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Number of results: 6
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Abstract

Removal of mercury(II) (Hg(II)) from aqueous media by a new biosorbent was carried out. Natural Polyporus squamosus fungus, which according to the literature has not been used for the purpose of Hg(II) biosorption before, was utilized as a low-cost biosorbent, and the biosorption conditions were analyzed by response surface methodology (RSM). Medium parameters which were expected to affect the biosorption of Hg(II) were determined to be initial pH, initial Hg(II) concentration (Co), temperature (T (°C)), and contact time (min). All experiments were carried out in a batch system using 250 mL fl asks containing 100 mL solution with a magnetic stirrer. The Hg(II) concentrations remaining in fi ltration solutions after biosorption were analyzed using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). Based on the RSM results, the optimal conditions were found to be 5.30, 47.39 mg/L, 20°C and 254.9 min for pH, Co, T (°C), and contact time, respectively. Under these optimal conditions, the maximum biosorbed amount and the biosorption yield were calculated to be 3.54 mg/g and 35.37%, respectively. This result was confi rmed by experiments. This result shows that Polyporus squamosus has a specifi c affi nity for Hg ions. Under optimal conditions, by increasing the amount of Polyporus squamosus used, it can be concluded that all Hg ions will be removed

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Authors and Affiliations

Yusuf Uzun
Tekin Şahan
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Abstract

In the present paper, elemental Fe, Cr and Ni powders were used to fabricate nano-structured duplex and ferritic stainless steel powders by using high energy planetary ball milling. We have studied the effect of milling atmosphere like wet (toluene) and dry (argon) milling of elemental Fe-18Cr-13Ni (duplex) and Fe-17Cr-1Ni (ferritic) powders for 10 h in a dual drive planetary mill. Stearic acid of 1wt. % was added during milling to avoid agglomeration. The dry and wet milled duplex and ferritic stainless steel powders were characterized by XRD, SEM and particle size analysis techniques. We have found that both the milling atmospheres have great influence in controlling the final particle morphology, size and phase evolution during milling. It was reported that dry milling is more effective in reducing particle size than the wet milling. The Nelson-Riley method of extrapolation was used to calculate the precise lattice parameter and Williamson-Hall method was used to calculate the crystallite size and lattice strain of both the stainless steel milled in argon atmosphere. Dry milled duplex and ferritic stainless steel were then consolidated by conventional sintering method at 1100, 1200 and 1300°C temperatures under argon atmosphere for 1 hour.

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Authors and Affiliations

R. Shashanka
Orhan Uzun
D. Chaira
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Abstract

In this study, metal matrix composite materials containing melt-spun Al-20Si-5Fe alloys and boron carbide was produced by high energy ball milling and then hot pressing at 200 MPa pressure and 450°C. Mechanical and microstructural characterizations were performed by using an optical microscopy, X-Ray diffractometer, and dynamic microhardness tester. It was observed that boron carbide particles were homogenously distributed in the microstructure and values of microhardness and elastic modules were averagely 830 MPa and 42 GPa, respectively.
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Authors and Affiliations

Fatih Kilicaslan M.
Uzun A.
E. Karakose
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Abstract

The purpose of the present study was to extract high added value titanium from Ti-doped Seaside Magnetite Concentrated (Ti-SMC), which has a high potential reserve for Ti-Fe with 4–6% Ti, 50–52% F e, 1–2% A l, and 1–2% Mg content by applying innovative, economical, environmentally friendly methods. A gitaion HCl leaching was applied to the Ti-SMC sample at different leaching temperatures (25–50–75–90°C), at acid concentrations (8–10–12 N ), and leaching times (30–60– –120–240 min) in atmospheric conditions. A fter the leaching experiments under the indicated conditions, the optimization of the leaching experiments was determined with Ti% recovery that dissoluted by elemental analysis, and the titanium recovery values reached the maximum value with increased leaching time at 50°C and 10 N HCl acid concentration; and 65% Ti was recovered in 30 minutes, 67% in 60 minutes, 74% in 120 minutes, and 82% Ti in 240 minutes. F or Ti-SMC, leaching was carried out at 50°C leaching temperature and at 10 N acid concentration for 480 minutes, and a 92% Ti extraction value was achieved. A ccording to the extraction results of all leaching experiments, the leaching temperature of 50°C, the acid concentration of 10 N , and the leaching time of 480 minutes were determined as the optimum conditions. In this study, it was emphasized that this resource is a potential reserve, which has not been used as a source before, with 92% Ti extraction with atmospheric acid leaching, which is an environmentally friendly method, consuming less energy than Ti-SMC, which is difficult and expensive to extract with traditional methods.
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Authors and Affiliations

Elif Uzun Kart
1
ORCID: ORCID
Mümin Kırman
1
ORCID: ORCID

  1. Marmara University, İstanbul, Turkey

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