Search

In this work, a photocatalytic process was used for removing metformin as a widely prescribed drug to reduce blood sugar in type 2 diabetes. Photocatalytic processes are one of the most common oxidation processes in degrading organic compounds. This study aimed to investigate the efficiency of Fe3+ doped TiO2 nanoparticles in degrading metformin in synthetic wastewater. Therefore, in the first step, Fe3+ doped TiO2 nanoparticles were synthesized by the sol–gel method and characterized using X-ray diffraction, energy-dispersive X-ray spectrometry, scanning electron microscopy, and pH(PZC) techniques. Then, the effects of parameters, such as the initial concentration of metformin (10–45 mg/L), catalyst dose (25–75 mg/L), pH (3–11), and time (30–150 min), were studied on the photocatalytic degradation of metformin. Results showed that by increasing the experimental parameters, including pH, catalyst dose, and contact time, the nanoparticle removal efficiency increased. Overall, these findings indicated that under optimum conditions, including pH = 11, nanoparticle dose of 75 mg/L, and contact time of 150 min, photocatalytic degradation can remove 93.8% of metformin with an initial concentration of 35 mg/L. Moreover, Fe3+ doped TiO2 nanoparticles with UV light (as a photocatalytic treatment system) have good efficiency in degrading metformin. [ABSTRACT FROM AUTHOR]

This study aimed to synthesise TiO2 nanoparticles (NPs) in pure rutile structure at moderate temperature without calcination and use them as the catalyst for alachlor removal under UV-C radiation. The crystal structure, composition, and particle size of the synthesised TiO2 NPs were analysed using an X-ray diffractometer (XRD) and a scanning electron microscope (SEM). The XRD spectra revealed the production of pure rutile TiO2. The individual and interactive effects of initial alachlor concentration (15–75 mg/L), TiO2 concentration (25–125 mg/L), pH (3–11), temperature (20–40 °C) and reaction time (15–75 min) on alachlor removal were investigated using the central composite design model based on the response surface methodology for experimental design, modelling and process optimization. The analysis of variance and multiple linear regression showed a good fit of the experimental data to the second-order polynomial model, with a coefficient of determination (R2) value of 0.8176 and a model F-value of 19.55975, implying that the model was significant. The results showed that decrease in pH and the initial alachlor concentration and increase in TiO2 concentration resulted in an increase in alachlor removal rate. The maximum rate of alachlor removal (98.44%) at optimum conditions occurred at pH = 5, alachlor = 30 mg/L, TiO2=100 mg, temperature = 35 °C and reaction time = 60 min. [ABSTRACT FROM AUTHOR]

In this study, Fe@Fe2O3 nanowires were applied in combination with electro Fenton (EF) process to decompose of carbamazepine (CBZ) drug in an electrochemical reactor using a graphite rod cathode and Ti/PbO2 anode. Response surface methodology (RSM) based on central composite design was used to optimize various parameters such as pH, current, FeSO4·7H2O, drug and Fe@Fe2O3 concentrations, and reaction time. The results of RSM showed a good statistical relationship between experimental values of CBZ removal and their predicted values using the suggested multi-parameter model. The efficacy of CBZ removal significantly enhanced with increasing density, Fe@Fe2O3 nanowire dose, and reaction time, while it was reduced with increasing pH, FeSO4·7H2O concentration, and initial concentration of the drug. The results on a percentage of contribution and the F-value (PC% = 42.99 and F = 346.4003) showed that Fe@Fe2O3 dose plays an important role in increasing the efficiency of the electro Fenton process. RSM results also revealed that EF process effectively removed 88.55% of CBZ and 65% of total organic carbon from aqueous solutions under optimum conditions; that is pH = 4, current = 0.18 A (current density = 5.14 mA cm-2), FeSO4·7H2O concentration = 3.87 mg L-1, CBZ concentration = 7.49 mg L-1, Fe@Fe2O3 dose = 1,050 mg L-1, and reaction time = 50 min. The utilized multi-parameter optimization approach revealed the presence of interactions between pH with FeSO4·7H2O concentration and pH with reaction time. As a conclusion EF process catalyzed by Fe@Fe2O3 nanowire can be used for the removal of pharmaceutical compounds such as CBZ from aqueous solutions. [ABSTRACT FROM AUTHOR]

Adsorption techniques are widely used to remove industrial wastewater contaminants, especially non-biodegradable colourants. In this study, Iranian zeolite clinoptilolite was synthesised using magnetic iron oxide as an inexpensive and efficient adsorbent. The results showed that using natural zeolite, the removal efficiency of 26.8.6% at pH = 3 reached 48% at pH = 9. However, the adsorption capacity of the modified clinoptilolite did not change by increasing pH; it ranged from 96.4% to 98.6%. Moreover, increase in the initial concentration of the dye did not have any effects on the removal efficacy of the modified clinoptilolite. Using natural zeolite, on the other hand, the adsorption capacity showed a significant decrease and reached less than 10% at the 200 mg/l dye concentration. At the optimal contact time of 45 min, the dye removal rate by the modified zeolite was more than 98% at the optimal dose of 0.5 g. Indeed, the adsorption isotherm complied with Freundlich equation. Overall, the results showed that in comparison to the natural zeolite, the adsorption capacity of the clinoptilolite modified by iron nanoparticles increased significantly due to the uniformity of the cavities and increase in the surface of the adsorbent. [ABSTRACT FROM AUTHOR]

A new strategy is proposed for the quantitative structure–electrochemistry relationship (QSER) in non-aqueous systems, based on the combination of theoretical properties of electrochemical analytes and empirical parameters of solvents. Modeling of the first reduction potential of some anthraquinone derivatives in three organic solvents (acetonitrile, N,N-dimethyl formamide and dimethylsulfoxide) was done using the proposed approach. Combining the properties of electrochemical solvent and solute in a single model, shows that the structural features of anthraquinones and also some properties of the solvents are effective in predicting the electrochemical behavior of this non-aqueous system. The correlation coefficients of cross validation and external test set were 0.93 and 0.96 respectively which indicate stability and prediction ability of the model. To the best of our knowledge, this is the first report on simultaneous including the features of analyte and solvent in a QSER. This work obtains a way to decrease hazardous experiences in non-aqueous solvents. [ABSTRACT FROM AUTHOR]

Co-presence of fluoride (F−) and nitrate (NO 3 −) in water causes numerous health complications. Thus, they should be eliminated by an appropriate method like the EC process. In this research, simultaneous removal of F− and NO 3 − from synthetic aqueous solution and groundwater has been considered by the EC technique under operational parameters like anode materials (un-coated (Al and Fe) and synthesized coated (Ti/TiRuSnO 2 and Ti/PbO 2)), cathode materials (Cu, St, and Gr), current density (12, 24, and 36 mA/cm2), inter-electrode distance (0.5, 1, and 2 cm), pH (5.5, 7, and 8.5), NaCl concentrations (0.5, 1, and 1.5 g/L), electrolysis time (15, 30, 45, 60, 90, and 120 min), NO 3 − concentrations (75, 150, and 225 mg/L), and F− concentrations (2, 4, 6, and 8 mg/L) for the first time in this research. The results proved that Al as non-coated anode and Cu as cathode electrodes were more effective in the co-removal of F− and NO 3 −. The maximum removal efficiencies of 94.19 and 95% were observed at the current density of 36 mA/cm2, 1 cm of inter-electrode distance, pH 7, 1 g/L of NaCl, and 90 min electrolysis time by Al–Cu electrode for F− (2 mg/L) and NO 3 − (75 mg/L), respectively. The higher efficiency of Al–Cu electrodes was due to the simultaneous occurrence of electrocoagulation, electroreduction, and electrooxidation processes. Al–Cu electrode application considerably diminished f- and NO3- concentrations in the groundwater. Health risk assessment proved that HQ of F− was significantly decreased after treatment by the Al–Cu electrode. Thus, the EC process using an appropriate and effective electrode is a promising technique for treating aqueous solutions containing F− and NO 3 −. [ABSTRACT FROM AUTHOR]

In this study, epoxidized soybean oil-grafted Fe 3 O 4 -SiO 2 nanocomposite (Fe 3 O 4 -SiO 2 -ESBO) containing a hydrophobic surface and hydrophilic polar functional groups was synthesized. The sorbent showed excellent dispersibility in aqueous solution and was utilized for magnetic solid phase extraction of trace amounts of rhodamine B in aqueous solution prior to its determination using UV–Vis spectroscopy. The sorbent was characterized by Fourier transform infrared spectroscopy, transmission electron microscopy and scanning electron microscopy. The magnetite nanoparticles had spherical shape with their grain size of < 20 nm. The effects of pH, sorbent mass, uptake time on the sorption of rhodamine B on Fe 3 O 4 -SiO 2 -ESBO were investigated using Box–Behnken design. The adsorption capacity of the sorbent was 1355 μg of rhodamine B per gram of sorbent. In optimal experimental conditions, the limit of detection, limit of quantification and enrichment factor of the proposed method were 3.94 μg L − 1 , 13.13 μg L − 1 and 26, respectively. The proposed method was successfully applied to the separation and determination of rhodamine B in dish washing liquid, match tips and tap water samples with recoveries in the range 96.40–98.10%. [ABSTRACT FROM AUTHOR]