Recep Boncukcuoğlu

Utilization of borogypsum as set retarder in Portland cement production

Abstract Boron ores are used in the production of various boron compounds such as boric acid, borax and boron oxide. Boric acid is produced by reacting colemanite(2CaO·3B 2 O 3 ·5H 2 O) with sulphuric acid and a large quantity of borogypsum is formed during this production. This waste causes various environmental problems when discharged directly to the environment. Portland cement is the most important material in the building industry. This material is produced by adding about 3–5% gypsum (CaSO 4 ·2H 2 O) to clinker as a set retarder. The aim of this study was to stabilize borogypsum, and to produce cements by adding borogypsum instead of natural gypsum to clinker. Concrete using cement produced with borogypsum was tested to find the mechanical properties and the test values were compared with those of concrete from cement with natural gypsum. Compressive strength of concrete from cement produced with borogypsum was found to be higher than that of natural gypsum. Also, the setting time of cement with borogypsum was longer than that of the Portland cement.

Utilization of trommel sieve waste as an additive in Portland cement production

Abstract Large quantities of industrial wastes form in boron industry in Turkey every year. These wastes have dual problems of disposal and health hazards. The wastes such as borax slime, tincal waste, concentration wastes and thromel sieve waste (TSW) contain impurities that accelerate the normal setting and hardening of building materials produced from them. In this study, it was aimed to stabilize TSW produced during manufacture of borax from tincal. The effects of TSW added on the mechanical properties of Portland cement prepared by adding TSW to clinker were investigated. The utilization of TSW in cement industry as an additive was tested and compared with other materials.

Adsorption of Ni(II) on ion exchange resin: Kinetics, equilibrium and thermodynamic studies

This article describes the ion exchange of a heavy metal Ni(II) from aqueous solutions onto a Dowex HCR-S, cationic resin. Batch adsorption studies were conducted to evaluate the effect of various parameters such as pH, resin dose, stirring speed, temperature, contact time and initial Ni(II) concentration on the removal of Ni(II). Adsorption rate increased with the increase in initial nickel concentration, stirring speed and temperature. Equilibrium adsorption isotherms were measured for the single component system, and the experimental data were analyzed by using Langmuir, Freundlich, Elovich, Temkin, Khan, Sips, Toth, Koble-Corrigan and Radke-Prausnitz isotherm equations. The Sips equation appears to fit the equilibrium data. Different models were tested for their applicability. Adsorption kinetic data were modeled using the Lagergren pseudo-first-order, Ho’s pseudo-second-order and Elovich models. It was found that Ho’s pseudo-second-order model could be used for the prediction of the system’s kinetics. Thermodynamic activation parameters such as ΔG*, ΔS* and ΔH* of the adsorption of Ni(II) on Dowex HCR-S cationic resin were also calculated.

Recovery of boron of the sieve reject in the production of borax

Abstract Boron ores are one of the most important underground richness of Turkey. Various boron compounds are produced from these ores. The most important one of them is borax. During the borax production process, a large quantity of the boron oxide (B 2 O 3 ) is discharged by the trommel sieve waste (TSW). Also, this waste causes different environmental problems when it discharged directly to the environment. In this study, evaluation of the reactor waste discharged directly to environment during borax production was investigated to recover B 2 O 3 and therefore to reduce the toxic effect of the waste. For this purpose, the TSW was leached by SO 2 -saturated water at various experimental conditions. It was found that the 90% of B 2 O 3 in the waste was recovered. In addition, about 80% of CaO in the waste dissolved in the leaching solution. A part of the dissolved CaO converted to CaSO 3 · 1 2 H 2 O and Ca(HSO 3 ) 2 which can be used in the paper industry and in other some industries.

Measurement of mass attenuation coefficients of some boron compounds and the trommel sieve waste in the energy range 15.746

Abstract Mass attenuation coefficients of some boron compounds ( H 3 BO 3 , Na 2 B 4 O 7 and B3Al2O3) and the trommel sieve waste (TSW) have been measured by using an extremely narrow collimated-beam transmission method in the energy range 15.746– 40.930 keV . The characteristic Kα and Kβ X-rays of Zr, Mo, Ag, In, Sb, Ba and Pr passed through H 3 BO 3 , Na 2 B 4 O 7 , B3Al2O3 and TSW were detected with a high-resolution Si(Li) detector. The measured values are compared with the theoretical ones obtained using the WINXCOM.

Adsorption of Methyl Violet Dye, A Textile Industry Effluent onto Montmorillonite—Batch Study

In this study, methyl violet (MV) dye adsorption from synthetically prepared solutions onto montmorillonite was investigated. Experimental parameters were selected as stirring speed, adsorbent dosage, initial dyestuff concentration, initial solution pH, ionic strength, and temperature. It was determined that adsorption rate increased with increasing stirring speed, initial dye concentration, solution pH, ionic strength, and temperature, but decreased with increased adsorbent dosage. The experimental data were analyzed by Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich isotherms, and it was found that the isotherm data were reasonably correlated by Langmuir isotherm. Maximum adsorption capacity of montmorillonite for MV dye was calculated as 230.04 mg g−1. Pseudo-first-order, pseudo-second-order, Elovich, and intraparticle particle diffusion models were used to fit the experimental data. Pseudo-second-order rate equation provided realistic description of adsorption kinetics. Thermodynamic parameters were calculated as 62.14 kJ mol−1, 59.55 kJ mol−1, 51.98 kJ mol−1, and 0.0242 kJ mol−1 K−1 for Ea, ΔH*, ΔG*, and ΔS* at 293 K, respectively. The value of the calculated parameters indicated that the physical adsorption of MV on the clay was dominant and the adsorption process was also endothermic. The positive values of ΔS° suggest the increased randomness. The positive ΔG° value indicated the un-spontaneous nature of the adsorption model.

Effect of some operational parameters on the arsenic removal by electrocoagulation using iron electrodes

Arsenic contamination of drinking water is a global problem that will likely become more apparent in future years as scientists and engineers measure the true extent of the problem. Arsenic poisoning is preventable though as there are several methods for easily removing even trace amounts of arsenic from drinking water. In the present study, electrocoagulation was evaluated as a treatment technology for arsenic removal from aqueous solutions. The effects of parameters such as initial pH, current density, initial concentration, supporting electrolyte type and stirring speed on removal efficiency were investigated. It has been observed that initial pH was highly effective on the arsenic removal efficiency. The highest removal efficiency was observed at initial pH = 4. The obtained experimental results showed that the efficiency of arsenic removal increased with increasing current density and decreased with increasing arsenic concentration in the solution. Supporting electrolyte had not significant effects on removal, adding supporting electrolyte decreased energy consumption. The effect of stirring speed on removal efficiency was investigated and the best removal efficiency was at the 150 rpm. Under the optimum conditions of initial pH 4, current density of 0.54 mA/cm2, stirring speed of 150 rpm, electrolysis time of 30 minutes, removal was obtained as 99.50%. Energy consumption in the above conditions was calculated as 0.33 kWh/m3. Electrocoagulation with iron electrodes was able to bring down 50 mg/L arsenic concentration to less than 10 μg/L at the end of electrolysis time of 45 minutes with low electrical energy consumption as 0.52 kWh/m3.

Effects of operational parameters on cadmium removal from aqueous solutions by electrochemical coagulation

Abstract The aim of present study is to investigate the feasibility of cadmium removal from water using electrocoagulation. Electrocoagulation (EC) is an electrochemical wastewater treatment technology with increased popularity and considerable technical improvements. In the study, effects of operating parameters such as initial solution pH, initial concentration (C 0), reaction time (t), stirring speed, and conductivity (κ) on cadmium removal from synthetic wastewater-containing cadmium in the batch electrocoagulation process were investigated. It was found from experimental results that initial solution pH is important parameter affecting cadmium removal. pH of initial solution was in the range of 3 to 6 in the experiments. The largest cadmium removal efficiency was obtained with pH 6. pH 6, obtained from initial solution whose pH was 6, reached an agreement with activity to pH diagrams for Al+3 species in equilibrium with Al(OH)3. Although specific energy consumption increased with decreasing cadmium c...

Pre-Treatment of Pistachio Processing Industry Wastewaters (PPIW) by Electrocoagulation using Al Plate Electrode

The objective of the present study is to assess the efficiency of electro-coagulation treatment of pistachio processing industry wastewaters (PPIW) using an aluminum plate electrode. The effect of some of the parameters was examined on the removal of chemical oxygen demand (COD), total organic carbon (TOC), and total phenols (TP) removal efficiency. The treatment was carried out in a batch system. The influences of current density (from 1 to 6 mA cm−2), initial pH of wastewater (from 2 to 8), constant pH of wastewater (from 3 to 7), stirring speed (from 100 to 500 rpm), and supporting electrolyte concentration (from 10 to 50 mg L−1 NaCl) on removal efficiency were investigated to determine the best experimental conditions. The evaluation of the physico-chemical parameters during the treatment by electrocoagulation showed that the best removal efficiency was obtained under the conditions of 180 min electrolysis time, wastewater with constant pH of 6, and 6 – mA cm−2 current density. Under such experimental conditions, COD, TOC, and TP removal efficiency were found to be 60.1%, 50.2%, and 77.3%, respectively, while energy consumption was 39.6 kW-h m−3. The results of the study show that the electrocoagulation can be applied to PPIW pre-treatment.

Boron removal by means of chemical precipitation with calcium hydroxide and calcium borate formation

Boron removal was investigated by chemical precipitation from aqueous solutions containing boron using calcium hydroxide. pH, initial boron concentration, amount of Ca(OH)2, stirring speed and solution temperature were selected as operational parameters in a batch system. The highest boron removal efficiency was reached at pH 1.0. Increasing initial boron concentration and amount of calcium hydroxide raised to boron removal efficiency. Boron removal efficiency was highest at a stirring speed of 150 rpm. The most important parameter affecting boron removal efficiency was solution temperature. Increasing solution temperature increased importantly boron removal. XRD analysis showed that CaB3O3(OH)5·4H2O, which is a borate mineral called inyoite, occurred between Ca(OH)2 and borate ions. As a result of the obtained experimental data, when the optimum operational conditions were selected, over 96% of boron removal efficiency was reached by this method.