A new adsorbent material, aluminum modified talc clay, was synthesized for phosphate adsorp - tion from solutions. The raw talc and aluminum coagulation were not effective than modified talc. Due to this reason, phosphate adsorption from synthetic solutions on modified talc was investigated in a batch system as a function of pH, time, concentration, temperature, solid amount and aluminum loading effect. Optimum conditions for modified talc were determined as pH (11), temperature (40°C), concentration (200 mg/L), time (20 min), solid amount (1 g/50 mL), and aluminum loading (1.5 g AlCl 3 /10 g talc/50 mL pure water). Optimization of phosphate adsorp - tion onto modified talc was realized by central composite experimental design using Minitab 16.0 program. The statistically importance sequence of parameters were dosage, dosage–dosage, pH–dosage, pH, pH–pH, concentration, dosage–concentration, pH–concentration and concentra -tion–concentration. The kinetics of removal obeyed the pseudo-second-order model rather than pseudo-first-order model. The isotherm data fitted well to the Langmuir isotherm. The thermo dynamic analysis of phosphate adsorption indicated non-spontaneous and physical adsorption of phosphate. The rate controlling mechanism for adsorption was particle diffusion. The XRD analysis for raw talc was done. FTIR-ATR analysises for raw, modified and phosphate adsorbed modified talc were done. SEM images before and after adsorption was interpreted. According to obtained results, the modified talc was found as an effective adsorbent for phosphate removal from uncomplex wastewaters for control of eutrophication and for production of drinking water. Maximum phosphate capacity was calculated as 37.45 mg/g.

In this study, boron removal from synthetic solutions and colemanite mine wastewater by coagulation method using in-situ generated zinc hydroxide from zinc chloride salt was investigated. The parameters for Jar test experiments were solution pH (8-12), concentration (50-750 mg/L), temperature (12-40oC), and zinc chloride dosage (1.0204-10.204 g). The saturation pH of zinc hydroxide is 8.93. The boron adsorption capacity reached to maximum value at pH value of 9 and this pH was selected as optimum value. Boron adsorption capacity increased with increasing concentration due to increasing driving force of concentration. High dosages increased the removal percentage. The adsorption of boron to zinc hydroxide had exothermic nature. The optimum conditions obtained from synthetic solutions were applied to the colemanite mine wastewater by 22 factorial design. The maximum boron adsorption capacity of zinc hydroxide from colemanite mine wastewater was calculated as 43.57 mg/g. The used material and process was promising for boron mine wastewater.

Boron adsorption onto lime soil from Balıkesir University campus was studied to evaluate the effects of irrigation water cations (Ca2+, Mg2+, K+ and Na+) and soil clays (kaolinite, montmorillonite, clinoptilolite clays). The concentrations for cations and boron were in the range of 0-1,450 mg/L and 0-700 mg/L, respectively. The experimental maximum boron capacity for cation effect was 0.764 mg/g and this value was seen to obtain at high cation and middle boron concentration (304.49 mg/L) in optimization graph. The maximum experimental boron capacity for clay effect was 1.08 mg/g and this value was obtained from optimization graph at 0.5828 g clinoptilolite, 0.1936 g montmorillonite, 0.5852 g kaolinite amounts. The borated-soil samples were successfully phytoremediated with potato plant and maximum intake of boron by the potato plant was 2,304.8 mg/kg plant. The plant dry weights decreased by increasing soil boron concentration and the potato plants did not grow at 203.56, 303.56, 403.56 mg/kg boron concentrations exhibiting toxic effects for potato plant. The studied soil concentrations for phytoremediation was 3.56, 13.56, 23.56, 33.56, 43.56, 53.56, 103.56, 203.56, 303.56, and 403.56 mg/kg boron.

In this study, boron removal from synthetic solutions and boron mine wastewater by coagulation method using in-situ formed Al(OH)3 from AlCl3 salt was investigated. The experimental parameter for synthetic solution was solution pH. The optimum condition for synthetic boron solutions was determined as pH (8). The ideal pH value obtained from the synthetic solutions was applied to the boron mine wastewater with concentration of 373.19 mg L-1 by 21×21 full factorial experimental design. The parameters in the design were dosage of aluminium chloride (5, 10 g) and dilution factor (1,10 fold). The aluminium hydroxide provided maximum 100% removal from mine wastewater at optimum conditions. Also, the data obtained were analyzed by means of Pareto chart and surface plot. P values for all the parameters were found as above 95% confidence limit value (p

In this study, the performance of Purolite S 108 resin for boron removal from solutions and boron mine wastewater in a column reactor was investigated. The investigated experimental parameters for synthetic solutions were initial pH, temperature, concentration, resin amount, solution flow rate and regeneration number. When the maximum adsorption capacity values of the resin were compared, the optimum removal conditions were determined as pH (9.5), concentration (1,000 mg/L), temperature (15 degrees C), resin amount (20 g) and solution flow rate (2.976 mL/min). The resin boron exchange capacity did not change significantly up to fifth resin use. Maximum capacity was calculated as 10.67 mg/g at 1,000 mg/L concentration. The boron exchange reaction of the Purolite S 108 resin was a slow process. The kinetics of boron removal by the resin was analyzed using the Adams-Bohart, Yoon-Nelson and Thomas models. The kinetic data showed fitness for two models except Adams-Bohart model. Also, an empirical kinetic model was developed for operation of resin column. The developed model from synthetic solution experiments was applied to the boron mine wastewater to estimate 4.55%, 45.5% and 83.33% breakthrough times for removal and recovery. The developed empirical model could estimated the these breakthrough times correctly. Resin was effective for boron.

In this study, iron hydroxide was in-situ generated from iron chloride in the jar test reactors and used for boron removal from both synthetic solutions and colemanite mine wastewater.  A time span of 32.5 minutes was enough for equilibrium between boron and iron hydroxide.  In the synthetic boron solutions, the variations of boron adsorption capacity of iron hydroxide were investigated by the experimental parameters chosen as pH (7-10), concentration (50-250 mg/L), iron chloride amount (2.5-10 g) and temperature (22.5-40 oC).  The optimum pH value for boron removal was determined as 7.  Because the higher boron concentrations supported to the boron uptake of iron hydroxide, the optimum boron concentration was 250 mg/L.  The boron uptake capacity of iron hydroxide increased with decreasing iron chloride dosage.  The boron adsorption onto the iron hydroxide was an exothermic process.  The optimum conditions obtained from the synthetic solution experiments were applied to the colemanite mine wastewater by 22 full factorial experimental design of factors which were dilution (1 and 10 fold) and iron chloride amount (5 and 10 g).  The optimization of boron removal by iron hydroxide was realized by analyzing Pareto chart.  Maximum capacity was calculated as 23.80 mg/g.

In this study, boron uptake from solutions by raw and modified talc clay was investigated.The raw talc mineral was modified in aluminum chloride solution.Firstly, the pH experiments were carried out by raw and modified talc.Due to the relatively low adsorption capacity of the raw talc, the modified talc was used in further experiments.Boron adsorption experiments for the modified talc were conducted by different initial pH of the solution, temperature, boron concentration and adsorbent amount.Optimum parameters for the modified talc were determined as pH (7), concentration (500 mg/L), temperature (25°C) and adsorbent dosage (0.8 g/50 ml).The optimum pH was determined as 9 for raw talc use.Maximum boron adsorption capacities for the modified talc and raw talc were calculated as 3.10 and 2.4 mg/g, respectively.The thermodynamic parameters such as enthalpy, entropy and Gibbs free energy change were calculated, and the boron adsorption had exothermic nature.The optimization of boron adsorption data for the modified talc was performed by applying 2 3 factorial experimental design.The isotherm analysis data best fitted to the Langmuir model than the Freundlich model.The kinetic data fitted to the pseudo-second-order model rather than the pseudo-first-order model.Boron adsorption onto modified talc was controlled relatively by particle diffusion.Attenuated total reflection fourier-transform infrared spectroscopy analyses were performed for modified talc and boron adsorbed modified talc samples.

In this study, optimum conditions of color removal from aqueous solution of anionic Reactive Black 5 (RB5) dye through the Fenton oxidation process were investigated. Central composite design (CCD) of response surface methodology (RSM) was used to optimize the Fenton process. The pH, dye concentration, Fe2+ dosage and H2O2 dosage were selected as independent variables of method, and design experiments were carried out. Intervals of independent variables were initial pH of solution pH (2.5-5.5), dye concentration (50-350 mg/L), Fe2+ dosage (25-55 mg/L) and H2O2 dosage (175- 425 mg/L) at a constant temperature of 30 degrees C. The color removal performance of Fenton reactive increased with decreasing pH value and dye concentration and increasing reactive amount. The experimental studies showed that the RB5 removal efficiency of Fenton oxidation was over 99%. The conditions of maximum removal were obtained as initial solution pH 2.5, dye concentration 120 mg/L, Fe2+ dosage 25 mg/L and H2O2 dosage 240 mg/L. A full quadratic model equation which interacts response variables with independent variables was developed. The model data agreed with experimental data very well. R-2 value confirming the reliability of the model equation was 96.19%.

In this study, the optimisation of COD removal from a real textile wastewater by Bigadic clinoptilolite was performed using Response Surface Methodology (RSM) by means of Minitab 17 programme. The applied experimental parameters were pH, dosage and temperature. The obtained optimum conditions were pH 4, temperature 15 degrees C and dosage 1 g/50 ml. The optimiser and contour plots were used for optimisation of data set, and regression models were developed for calculation of model responses for a given any experimental parameters. Adsorbent capacity (q), COD and colour removal (%) values determined by RSM at optimum conditions were 31.01 mg/g, 61.8 and 29.69, respectively.

ABSTRACT In this study, boron removal from synthetic solutions using Purolite S 108 resin converted to hydroxyl form was investigated. Experiments were carried out in batch mode as a function of pH (4–10), concentration (50–500 mg/L), and resin-to-solution ratio (1–2.5 g/50 mL). Optimum pH value was determined as 10 and exchange capacity increased with increasing concentration. Boron exchange capacity of the resin increased at low solid-to-solution ratios. A 23 full factorial experimental design was applied to determine the optimum values and degree of importance of parameters. The low (1) and high (2) levels of the parameters were 3 and 7 for pH, 500 and 1,000 mg/L for concentration, and 1 and 2 g/50 mL for solid-to-solution ratio, respectively. The optimization of the parameters was done by interpretation of cube plot and Pareto chart. At 87% confidence level, the importance sequence of parameters and their interaction were as follows: concentration, pH-concentration interaction, and pH had positive effect on capacity. Solid amount, pH-solid amount, and concentration–solid amount interactions had negative effect on the capacity. Maximum capacity was calculated to be 25.5 mg/g. The kinetic data fitted to the pseudo-second-order model and rate controlling steps were liquid film and ash layer diffusion.

Dyes are toxic chemicals and the main source of color pollution in the textile wastewaters. Therefore, the use of illite clay as an adsorbent to remove methyl violet dye from solutions was investigated in this study. Equilibrium experiments were carried out in batch mode as a function of temperature, ionic strength, and pH. The equilibrium was attained within 24 hours. The capacity of illite clay increased when pH, temperature, and ionic strength were raised. Four adsorption isotherm models, viz, the Langmuir, Freundlich, Khan, and Sips, were used to analyze the equilibrium data. The nonlinear optimization technique was used to fit the data to the isotherm models, and for this purpose five error functions were used. The equilibrium data could be explained by the Sips isotherm model, and among the entire error equations generally the HYBRID error function provided the lowest sum of the normalized error values. Thermodynamic parameters indicated that dye adsorption had endothermic and unspontaneous nature. Also, the positive enthalpy change indicated that dye uptake occurred by physical binding. The maximum dye capacity of illite was found as 159.95 mg g(-1) at 60 degrees C. High dye capacity exposed that illite would be used effectively in cationic dye removal.

In this study, ion exchange was applied to artificial boron solutions for boron removal by boron selective Purolite S 108 in a batch reactor. The ion exchange experiments were carried out as a function of initial solution pH, resin-to-solution ratio, stirring speed, temperature, concentration, regeneration, and time. Optimum removal conditions for 400 mg/L initial boron concentration were determined as pH 8.5, temperature 15 degrees C, stirring speed 300 rpm, and resin-to-solution ratio 36 g/500 mL. Maximum boron removal at a concentration of 400 mg/L was obtained as 100%. The highest boron adsorption capacity of the resin was obtained as 9.31 mg/g. The regeneration of the resin was realized by consecutive acid stripping-neutralization-washing treatments. The resin ion exchange capacity values for the first four cycles were found as 8.5, 9.69, 9.37, and 8.45 mg/g, respectively. The obtained kinetic data followed the pseudo second-order model rather than the pseudo first-order kinetic model. Particle diffusion was found as the dominant rate controlling mechanism for boron removal. The activation energy of the complexation reaction between boron and the resin was calculated as 33.5 (kJ/mol). An activation energy of <50 kJ/mol generally indicates a film and particle diffusion controlled process, whereas higher values represent chemical reaction processes. Furthermore, based on the adsorption capacity approach an empirical model was developed.

ABSTRACT The removal of iron (Fe3+), originating in raw colemanite, from saturated boric acid solution is important in the production of pure boric acid. In this study, the kinetics of iron ion removal from saturated boric acid solution was studied by ion exchange technology using Amberlite IR–120, a strong acidic resin. The experiments were carried out as a function of solution pH, reaction temperature, resin-to-solution ratio, and resin contact time. Optimum conditions were determined as solution pH = 1.3, reaction temperature 313 K, resin-to-solution ratio 4.9625 g/250 mL, and 20 min contact time. Under these conditions, maximum iron removal was about 99%. Also, data calculated from a mass balance equation were employed for pseudo-first-order and pseudo-second-order kinetic equations. The pseudo-second-order kinetic equation was the equation which best fit the data. Furthermore the sorption mechanism was also investigated using diffusion models such as film diffusion, pore diffusion, and moving boundary process. It was found that rate limiting steps in the ion exchange reaction were both film and pore diffusion. Activation energy of the ion exchange reaction was calculated as 23.64 kJ/mol and this indicated a diffusion controlled process. Based on adsorption capacity approach, an empirical kinetic model was developed to predict operational conditions of the batch process as follows:

Boron pollution has a vital importance in Bigadic boron mine in Turkey because the wastewaters of the mine are stored in a soil dam that threats the underground water quality. In this study the optimization of boron removal from the boron mine wastewater using Purolite S 108 resin was investigated by means of a 2(3) full factorial experimental design. Experiments were carried out in batch mode as a function of pH, temperature and resin-to-solution ratio. The low (1) and high (2) levels of the parameters for pH, temperature and resin-to-solution ratio were 2.5 and 10, 12 degrees C and 40 degrees C and 1 g/50mL and 2 g/50mL respectively. Boron adsorption capacity of the resin increased with low temperature, low resin-to-solution ratio and high pH. When the probability constants (p<0.05) at 95% confidence level were taken into consideration, only pH was found as statistically important parameter. The optimization of the parameters to obtain optimum conditions was done by interpretation of cube plots, Pareto chart and contour plots. A time span of 48 hours was enough to reach the equilibrium. Adsorption data were analyzed with the Langmuir and Freundlich isotherms. Data fitted to the Langmuir isotherm with a coefficient of determination value of 0.988. Maximum adsorption capacity was calculated as 12.87 mg g(-1). The fixed bed kinetics of boron adsorption onto resin could be explained by the Thomas and Yoon-Nelson models with a coefficient of determination value of 0.938. The fixed bed capacity of the resin was calculated as 12.71 mg g(-1).

The determination of surface properties of montmorillonite clay is an important criterion for establishment of its adsorption ability against anionic and cationic species from wastewaters. In this study, electrokinetic surface properties of montmorillonite were investigated using the microelectrophoresis technique. The zeta-potential (zeta) analysis of the montmorillonite was done by streaming potential measurements as a function of salt concentration and equilibrium pH of solution. It was found that the zeta potential of the clay particles was negative for monovalent cations (KCl, LiCl, NaCl) added to solution phase. Divalent cations (CaCl2, Ca(NO3)(2), Pb(NO3)(2)) could provide a neutral charge at just maximum concentrations. In addition, montmorillonite had a negative charge even at pH 2 and only trivalent cations (Fe(NO3)(3), FeCl3) provided positive surface charge at just maximum concentration. The characterization of the montmorillonite was performed by using XRD, XRF, FTER, SEM imaging, and N-2-BET analyses. The determined porous structure and strong negative surface charge of the montmorillonite showed that this clay would be used effectively in removal of cationic species from waters.

The copper causes important health problems risk when it exists at high concentrations in drinking waters and daily feeds. Therefore, in this study, copper adsorption from solutions onto illite clay was investigated in batch mode as a function of the initial solution pH (3-6), temperature (30-60 degrees C) and ionic strength (0- 0.1 mol/L-1 NaCl). The equilibrium was attained within 24 hours. Optimum conditions were determined as pH 6, temperature 60 degrees C and 0 mol/L-1 NaCl concentration. The isotherm data followed the S-class isotherm. The reason of this S-class isotherm was either solute-solute attractive forces at the surface causing cooperative adsorption or a competing reaction such as complexation with a ligand. Mathematically, the isotherm data were explained with the sum of several single Freundlich models. Also, the thermodynamic parameters of the process were calculated. Positive values of Gibbs free energy change (Delta G degrees) indicated that the adsorption process was unspontaneous. As the enthalpy change (Delta H degrees) had positive value for all the parameter intervals, copper adsorption was concluded to be physical and endothermic process. The positive entropy values indicated that the randomness at solid-liquid interface increased with concentration decrease. Maximum copper adsorption capacity of illite clay was calculated at 60 degrees C as 1.823x10(-5) mol/g. Furthermore, an empirical model was developed to determine the thermodynamic parameters of the process and operation conditions of the batch reactor as follows.

Bir zeolit turu olan klinoptilolit minerali dogal katyon degistiricilerden bir tanesidir. Bu calismada iyon degisimi metodu ile Bigadic klinoptiloliti kullanarak cozeltilerden bakir iyonlarinin giderimi arastirilmistir. Deneyler kesikli modda cozelti pH, sicaklik, iyon siddeti, NaOH ve KOH ile sartlandirmanin bir fonksiyonu olarak gerceklestirilmistir. Iyon degisimi reaksiyonu dengeye 24 saatte gelmistir. Klinoptilolitin adsorpsiyon kapasitesi yuksek pH, yuksek sicaklik ve dusuk iyonik siddet ile artmistir. Ham klinoptilolitin NaOH ve KOH ile sartlandirilmasi sirasiyla 10.4 ve 10.06 kat kapasite artisi saglamistir. Kapasitenin sicaklik artisi ile artmasi prosesin endotermik dogada oldugunu gostermistir. Ayrica, bakirin klinoptilolit ile iyon degisimi reaksiyonunun yuksek sicakliklarda kendiliginden daha kolay gerceklesecegi bulunmustur. Klinoptilolitin maksimum kapasitesi NaOH ile sartlandirma sonrasinda 48.45 mg g-1 olarak hesaplanmistir. Sorpsiyon denge verileri Langmuir ve Freundlich modelleri ile analiz edilmistir. Izotherm verilerinin Langmuir izotermine uyumunun Freundlich izoterminden cok daha iyi oldugu gorulmustur. Elde edilen sonuclar, Bigadic klinoptilolitinin ozellikle NaOH ile sartlandirma sonrasinda atik sulardan bakir gideriminde etkili bir sekilde kullanilabilecegini gostermistir