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In this study, the efficiency of the synthesised Ag/TiO2/Fe3O4 catalyst in the removal of endosulfan and metabolite formation by the photocatalysis process, the effect, and optimisation of the ambient conditions were investigated under UV–C light source. Photocatalysis process for endosulfan removal and degradation to metabolites was optimised with Taguchi experimental design method and the results were evaluated statistically by analysis of variance. Light intensity, amount of catalyst, initial endosulfan concentration, pH, and time were chosen as controllable parameters. The highest S/N ratios on the based on parameters were obtained at 27 W light power, pH 4, 0.5 g/L catalyst amount, 60 min reaction time and 4 mg/L initial endosulfan concentration. Since these values, at which the highest removal rate will be achieved, were not found in the experimental design, a confirmation experiment was performed and the removal was obtained as 93.2%. It was found that the most effective parameters on the removal efficiency were the initial endosulfan concentration and pH, respectively. As a result of analysis of variance, Fcritical values showed that the effects of light power, catalyst amount and reaction time on endosulfan removal were not statistically significant. When the P values are examined, it is seen that there is a significant difference between the initial endosulfan concentration and the levels of the pH factor for endosulfan removal. No formations of endosulfan sulphate, endosulfan ether, and endosulfan lactone were observed at high concentrations while endosulfan was removed. [ABSTRACT FROM AUTHOR]

In this study, the efficiency of conventional drinking water treatment processes (coagulation-flocculation and chlorination) for endosulfan removal and metabolite formation were investigated. Taguchi experimental design and analysis of variance (ANOVA) were applied using Minitab program. The highest removal efficiency was obtained as 65% at 6 mg/L initial endosulfan concentration, 30 mg/L aluminium sulfate dose and pH 7, in the coagulation-flocculation experiments. In chlorination experiments, it was determined that the variables of initial endosulfan concentration, chlorine dose, pH and contact time contributed 55.84%, 21.25%, 5.74% and 3.48% to the endosulfan removal, respectively, according to the ANOVA results. The presence of endosulfan metabolites like endosulfan ether, sulfate, and lactone were also detected and measured. P values were obtained only in endosulfan sulfate formation as a result of chlorination, lower than 0.05 for initial endosulfan concentration, chlorine dose and time parameters; apart from this, P values were not statistically significant in all other experiments. [ABSTRACT FROM AUTHOR]

In this study, the removal efficiency of endosulfan as a persistent organic pollutant and formation of its metabolites were investigated using Ag/TiO2/Fe3O4 photocatalyst under visible and UV-A light. Light intensity, catalyst amount, initial endosulfan concentration, initial pH and time were determined as controllable factors for Taguchi experimental design. The highest removal efficiencies of endosulfan were achieved as 86.14% and 85.46% for visible and UV–A light sources, respectively. According to the greatest best criterion, the level at which the highest S/N ratio was obtained for each parameter was accepted as the optimum value. As a result of the validation experiments, 94.2% and 91.9% efficiency were obtained for visible and UV-A light, respectively. The metabolite formations of endosulfan (endosulfan sulfate, ether, and lactone) remained below 7% in all experiments on a concentration basis. In the reuse experiments of the magnetically recovered photocatalyst, high removal efficiency of around 80% was obtained after four cycles. The removal efficiencies were found to be 86.7% and 84.8%, for real samples taken from the drinking water treatment plant inlet and the spring water network injected with endosulfan under optimal photocatalysis experimental conditions, respectively. It has been shown that nitrate and sulfate anions, which are in significant concentrations in raw water samples, have very little effects on endosulfan removal. The overall results showed that the Ag/TiO2/Fe3O4 photocatalyst was produced successfully, the catalyst was highly effective in the mineralization of endosulfan in synthetic and real water samples under UV and visible light, and effective yields could be obtained even with reuse. Highlights: Endosulfan removal efficiencies of 94.2%, 86.7% and 84.8% were achieved in synthetic, raw water and spring water samples, respectively, and no formation any metabolites under visible light. 77.23% removal efficiency was obtained even after five consecutive uses of the catalyst. A major advantage of this technology is that no chemical oxidants are added in the process and no sludge is produced as a reaction residue. Taguchi and ANOVA analyzes showed that the most effective parameters in endosulfan removal were initial endosulfan dose and pH. [ABSTRACT FROM AUTHOR]

In this study, the efficiency of different electrode pairs in the treatment of strained yoghurt wastewater with electrochemical oxidation method and the operating conditions in the reactor (distance between electrodes and applied potential) in specific energy consumption (SEC) for COD removal were investigated by applying the Taguchi experimental design and ANOVA analysis. For different electrode pairs, the highest COD removal was obtained as 24.79–28.9%, and it was observed that the electrode type did not have a significant effect on organic matter removal. It has been found that the operating conditions for different electrodes show similar trends for SEC in COD removal. The applied potential for all electrodes was determined as the most effective operating condition, followed by the reaction time and the distance between the electrodes. According to the results of ANOVA, the correlation coefficients of different electrode pairs were determined in the range of 82.33–91.21% for the SEC in COD removal. SEC under the studied experimental conditions is between the following values: 0.0019–2.5695, 0.0011–0.5702, 0.0007–0.5721, and 0.012–0.3641 kW h kg COD−1 for steel (anode)–steel (cathode), graphite (anode)–graphite (cathode), graphite (anode)–steel (cathode), and BDD (anode)–graphite (cathode) electrode pairs, respectively. It is thought that the electrochemical oxidation process will be a good alternative treatment method for strained yoghurt wastewater, which has a very high COD content and low pH value, as a post-treatment unit or in combination with other methods, due to an effective COD removal at low reaction times and low SEC. [ABSTRACT FROM AUTHOR]

In this study the magnetic nanocomposite material was synthesized with Fe3O4 impregnated to sugar beet pulp using chemical precipitation technique. Ni(II) removal performance of magnetic nanocomposite was investigated under different environmental conditions such as contact time, adsorbent dose, pH, initial heavy metal concentration, etc. The experimental studies have shown that, 81.2% Ni(II) removal efficiency was achieved at optimal conditions (25 mg/L initial Ni(II) concentration at 40 minute contact time, 200 rpm shaking speed, 5 g/L nanocomposite dose and pH 6.6). Freundlich and Langmuir isotherm experiments were performed and correlation coefficients were determined as 94.5% and 99.4%, respectively. The maximum adsorption capacity of material was achieved as 9.36 mg/g. These findings indicate that the adsorption that takes place is a monolayer process. The results of the pseudo-second order kinetic model (R2 = 0.9947) indicate the chemisorptions process is used for Ni(II) removal using the electrostatic interaction. Thermodynamic studies illustrated that Ni(II) adsorption onto nanocomposite are exothermic and causes a decrease in the entropy. The adsorption of Ni(II) ions is non-spontaneous except for at low temperature and low initial concentrations. Nanocomposite characterization was illuminated with XRD, FT-IR, BET, TGA, TEM, SEM/EDX analysis. In this study, it was aimed to synthesis new adsorbent using sugar beet pulp together with Fe3O4 under suitable conditions, obtain a magnetic nanocomposite, and examine the reusability and recovery properties of the produced material. The use of industrial wastes as an adsorbent material provides both a solution to the problem of the removal of wastes and a reuse method for the use of wastes as a low cost adsorbent for a useful purpose. Therefore, it has two advantages: There is a need to investigate the feasibility of investigating all possible industry-based cheap adsorbent sources as well as the removal of heavy metals for the production of a reliable and harmless adsorbent. [ABSTRACT FROM AUTHOR]

In this study, a magnetic new nanocomposite was synthesised using an agricultural waste (peanut hull), iron (II) sulphate and iron (III) chloride by co-precipitation method. The structure of magnetic nanocomposite was illuminated with Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, X-ray Diffraction Spectroscopy techniques; thermogravimetric and Brunauer-Emmett-Wires analysis. Effects of different ambient conditions such as contact time, pH, adsorbent dose and initial nickel concentration on removal of nickel ions were investigated. 82.8% nickel removal efficiency was achieved for 200 mL reactor volume including 10 mg/L initial nickel concentration at 25°C constant ambient temperature. According to the results of batch experiments, second-order kinetic model and Langmuir isotherm model was found to be compatible with datas. Nickel removal using magnetic nanoparticle synthesised with agricultural waste is a promising method because of low cost, separation simplicity and efficiency adsorbent. [ABSTRACT FROM AUTHOR]

In this study, photochemical deposition and co-precipitation methods were used to synthesise Ag/TiO2 and magnetic Ag/TiO2/Fe3O4 photocatalysts, respectively. The physical and chemical properties of the Ag/TiO2 and Ag/TiO2/Fe3O4 photocatalysts were characterised by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FT-IR) analyses. The synthesised photocatalysts were used to remove Reactive Red 195 (RR195) dye the most commonly used in the textile industry. The photocatalytic and sonophotocatalytic removal was investigated using different light types such as UV-A and visible light. In the optimum conditions (UV-A and visible light intensity 27 W, 25 mg/L initial RR195 concentration, pH 6 ve 0.1 g/L catalyst dose) of photocatalysis, the photodegradation of magnetic Ag/TiO2/Fe3O4 was found 72% at 120 min irradiation of visible light but the degradation was 65% at 30 min irradiation of UV-A light. While in case of the sonophotocatalysis, the degradation of magnetic Ag/TiO2/Fe3O4 was found 85% at 120 min irradiation of visible light but the degradation was 85% at 30 min irradiation of UV-A light. [ABSTRACT FROM AUTHOR]

• The silica gel supported dinitro calix[4]arene cage was successfully prepared, characterized, and used for methylene blue (MB) adsorption for the first time. • The applicability of DNCC for MB adsorption in real samples such as tap water and textile wastewater was investigated. • MB adsorption by DNCC was comprehensively evaluated in terms of thermodynamics, kinetic, and isotherm. • The MB uptake of DNCC was determined to be 212.770 mg g−1. The silica gel supported dinitro calix[4]arene cage (DNCC) was successfully prepared by immobilization of 3-glycidoxypropyl-bonded stationary phase (GBS) on p-tert- butylcalix[4]arene derivative having p -nitro benzyloxy moieties. The structural and composition analysis of the DNCC was performed by FT-IR, XRD, EDX, SEM, BET, and TGA techniques. After that, the proposed polymeric material as an adsorbent was used for the adsorption of methylene blue (MB) from aqueous solutions. Initial adsorption experiments demonstrated that DNCC showed outstanding performance for the removal of MB from aqueous solutions. Furthermore, many adsorption experiments were performed to evaluate the effects of some adsorption criteria on the MB adsorption. The MB adsorption capacity of DNCC was obtained approximately 212.770 mg g−1. Besides, thermodynamic parameters were evaluated and it was concluded that the MB adsorption came true in exothermically and spontaneously. Adsorption phenomena of MB on DNCC were clarified by the investigation of isotherm and kinetic criteria. Finally, the applicability of proposed adsorbent for MB adsorption was investigated in real samples such as tap water and textile wastewater. [ABSTRACT FROM AUTHOR]