Şahinde Demirci

Wastewater treatment at the petroleum refinery, Kirikkale, Turkey using some coagulants and Turkish clays as coagulant aids

Abstract In this study, waste water of Kιrιkkale Refinery (Turkey) was treated with coagulants (alum, ferric chloride, ferrous sulfate and lime) and coagulant aids (polyelectrolytes: anionic, cationic, nonionic) and some Turkish clays namely Samas, Canbensan, Ceylan, Hasandede and Keskin in order to see their effects in clarifying the waste water before biopurification. The results showed that local clays (Hasandede and Keskin) are as efficient as bentonites (Samas, Canbensan and Ceylan). The clarifying efficiency of clays in combination with coagulants shows almost the same results of about 90%. The effect of coagulants, FeCl 3 , FeSO 4 and CaO, was similar to that obtained with Al 2 (SO 4 ) 3 . The efficiency of polymeric materials especially cationic and anionic polymers was found to be better than that obtained with clays.

Effect of airborne particle on SO2–calcite reaction

In modern urban atmosphere, sulphur dioxide (SO2) attacks calcite (CaCO3) in calcareous stone-producing gypsum (CaSO4·2H2O) which forms crust at rain sheltered surfaces and accelerates erosion at areas exposed to rain. The airborne particles collected on stone surfaces have always been considered to enhance the gypsum crust formation and thus it is believed that they should be removed from the surface to decrease the effects of SO2. In this study, our aim was to investigate this event by carrying out a series of experiments in laboratory using pure calcium carbonate powder to represent calcareous stone. Sodium montmorillonite, activated carbon, ferric oxide, vanadium pentoxide and cupric chloride were mixed in the pure calcium carbonate powder as substitutes of the airborne particles in the polluted atmosphere. The samples have been exposed at nearly 10 ppmv SO2 concentrations at 90% relative humidity conditions in a reaction chamber for several days. The mineralogical composition of the exposed samples were determined by X-ray diffraction (XRD) analysis and infrared spectrometer (IR). Sulphation reaction products, calcium sulphite hemihydrate, gypsum and unreacted calcite, were determined quantitatively using IR. Exposed samples have also been investigated morphologically using a scanning electron microscope (SEM). Experimental results reveal that calcium sulphite hemihydrate is the main reaction product of the SO2–calcite reaction. It turns out that airborne particles play an important catalytic role in the oxidation of calcium sulphite hemihydrate into gypsum, although their presence does not very significantly affect the extent of sulphation reaction. This behaviour of airborne particles is explained by the presence of liquid film on the calcium carbonate surface where a series of reactions in the gas–liquid–solid interfaces takes place.

Changes in the structure of ulexite on heating

Abstract On heating, hydrated boron minerals, colemanite and ulexite lose their water of crystallisation while undergoing various mineralogical and structural changes. In this study, the nature and mechanisms of the thermal reactions of ulexite have been determined by TG, DTG and DTA. The changes in the structure have been investigated by XRD, SEM, and Hg-porosimetry. Thermal decomposition of ulexite occurred within the temperature range 60–500°C with two dehydration stages proceeded by two dehydroxylation stages. The structure was first transformed into NaCaB5O6(OH)6·3H2O within 60–180°C, then into NaCaB5O6(OH)6·H2O within 151–260°C. Amorphisation took place along with dehydroxylation. The structure was first transformed into a multi-domain heterogeneous matrix consisting of NaCaB5O6(OH)6·H2O and an amorphous phase to X-ray during the first stage of dehydroxylation within 180–260°C. Then remaining hydroxyl groups removed between 260 and 500°C. The sample has become completely X-ray amorphous. During the gradual liberation of water vapour, the structure developed numerous microcracks and had exfoliated without decrepitating. The microcracks increased the degree of porosity and the structure became more easy to grind. Furthermore, the amorphous structure recrystallised as NaCaB5O9 at 636°C and transformed into CaB2O4. Any remaining NaB3O5 after 855°C was amorphous.

Treatment of sugar beet juice with bentonite, sepiolite, diatomite and quartamin to remove color and turbidity

Abstract We investigate the efficiency of five Turkish bentonites (Samas, Canbensan, Karakaya-Resadiye, Karakaya-Cankiri and Karakaya-Beyaz), a sepiolite, a diatomite and dioctade-cyldimetlhyl ammonium chloride (Quartamin D86) at removing color and turbidity from sugar beet juice. These minerals were added directly as a solid or as a suspension in water. The addition of bentonites was carried out after acid activation or without pretreatment. Bentonites, sepiolite and diatomite were added separately or with a certain amount of quartamin (600 ppm). The decolorization produced by quartamin with bentonites was about 34%, for quartamin with sepiolite the decolorization was 44.0% and for quartamin with diatomite 31.5%. Since diatomite is already used as filter aid, its application, with quartamin requires almost no change in the process, and is therefore recommended.

A parametric comparative study of electrocoagulation and coagulation using ultrafine quartz suspensions

This paper attempts to compare electrocoagulation using aluminum anodes and stainless steel cathodes with conventional coagulation by aluminum sulfate dosing on aqueous suspensions of ultrafine quartz. Several key parameters affecting the efficiency of electrocoagulation and coagulation were investigated with laboratory scale experiments in search of optimal parameter values. Optimal values of the parameters were determined on the basis of the efficiency of turbidity removal from ultrafine quartz suspensions. The parameters investigated in the study were suspension pH, electrical potential, current density, electrocoagulation time, and aluminum dosage. A comparison between electrocoagulation and coagulation was made on the basis of total dissolved aluminum, revealing that electrocoagulation and coagulation were equally effective at the same aluminum dosage for the removal of quartz particles from suspensions. Coagulation, however, was more effective in a wider pH range (pH 6-9) than electrocoagulation which yielded optimum effectiveness in a relatively narrower pH range around 9, where, in both methods, these pH values corresponded to near-zero zeta potentials of quartz particles. Furthermore, experimental results confirmed that electrocoagulation could display some pH buffering capacity. The kinetics of electrocoagulation was very fast (<10 min) in approaching a residual turbidity, which could be modeled with a second-order rate equation.

Activation of some Turkish bentonites to improve their drilling fluid properties

Abstract In this study three Turkish bentonites (Samas, Canbensan and Ceylan) were tested for their potential use in drilling fluids. The drilling-mud quality of the bentonites from Canbensan and Ceylan were significantly improved with some additives such as salts (Na2C03, Na2SO4,Al2(SO4)3), gypsum, high molecular weight polymers, polyacrylamide, polyacrylic and sodium carboxymethyl cellulose. Salts were, found not to be as effective as polymeric materials for this purpose.

Raw Material Characteristics and Technological Properties of some Medieval Glazed Ceramics and Tiles in Anatolia

Byzantine and Seljuk cultures are two important overlapping periods in Anatolia during medieval times. Both cultures had special significance in the production of glazed pottery. In architecture, Seljuk culture had further expanded the use of ceramics as glazed tiles in the buildings. The Seljuk glazed tiles were mainly of mosaic and plain tile types. Only monochrome opaque turquoise and monochrome transparent violet-black coloured tiles were examined in this study. The pottery pieces studied represent the deep bowls with fine sgrafitto decorations coming from three archaeological sites namely Ephesus-Byzantine, Iznik-mixed and Korucutepe-Seljuk sites. The potsherds and tiles were analysed to determine the characteristics of body, slip and glaze parts in terms of raw materials composition and firing temperature using various analytical techniques. In addition, the physical properties and the ultrasonic velocity values of the body parts were examined. The results show that tiles are more porous, less dense and have lower ultrasonic velocity values than those of pottery bodies. Tile bodies have moderately vitrified matrix with large sized (~500 μm) particles of quartz added as temper and composed of low-calcareous clay. Temper aggregates do not seem to be used in the potteries.In the tiles, there is no slip between glaze and the body. Monochrome black glaze is alkaline glaze. Manganese and iron are the efficient elements in the development of violet-black tones. The monochrome turquoise glaze is tin-opacified leadalkali glaze, copper being the efficient element in turquoise colour. The potteries were all glazed over a slip having an illitic clay composition together with quartz. Potteries from Ephesus Byzantine site are high lead glazes, while the ones from Korucutepe Seljuk site are lead alkali glazes. Iron is the efficient element in the colouring of yellow, honey and brown coloured glazes while iron and copper are the efficient elements in the colouring of green glazes.

Study of adsorption characteristics of long chain alkyl amine and petroleum sulfonate on silicates by electrokinetic potential, microflotation, FTIR, and AFM analyses

ABSTRACT The long-chain alkyl amines and petroleum sulfonates are mostly used to remove unwanted minerals from feldspar ores in acidic pHs. In this study, their adsorption characteristics on pure albite and quartz were investigated by electrokinetic potential measurements, microflotation tests, Fourier transform infrared spectroscopy, and atomic force microscopy studies. According to the results, amine had strong influence on zeta potentials of both albite and quartz turning them positive and resulting over 90% flotation recovery at certain pH values. Petroleum sulfonate, on the other hand, was less effective in terms of both zeta potential values and flotation recovery responses of albite. Although albite and quartz had different zeta potentials and flotation recovery responses with each collector, they displayed similar adsorption bands of CH2 group over fingerprint region and adsorption layers with different intensities after being treated with the collectors. However, the adsorption of each collector on the minerals was altered by rinsing with acetone indicating that the interaction of the collectors with albite and quartz surfaces were mostly by Coulombic forces and hydrogen bonding.