In the present research, laundry wastewater treatment is studied using the electrocoagulation/electroflotation process. For the optimization of treatment conditions such as electrode type (Al–Al, Al–Fe, Fe–Fe, and Fe–Al), initial pH (5–9), current (0.54–2.16 A), and application time (15–60 min), response surface methodology is used. Removal efficiencies of chemical oxygen demand (COD), color, anionic surfactant, microplastic, and phosphate are studied. It is determined that the most effective removal is obtained with 2.16 A current, pH 9, and 60 min reaction time using Fe–Al electrode. Here, 91%, 94%, 100%, and 98% removal efficiencies are achieved for COD, surfactant, color, and microplastic, respectively. The operating cost of the combined process is calculated as $1.32 m−3 for the optimum removal parameters. The adsorption kinetics study shows that the removal follows second‐order kinetics. The laboratory‐scale test results indicate that the electrocoagulation/electroflotation process is feasible for the treatment of laundry wastewater.

The aim of this study is to investigate the production conditions of silver nanoparticles (NPs) in the presence of AgNO3 with the fungal cytoplasmic fluid (FCF) of white rot fungus Coriolus versicolor. In this study, parameters such as pH, AgNO3 concentration and FCF ratio of C. versicolor were optimized. C. versicolor was grown in SBM and then kept in ultrapure water to obtain FCF for synthesis of the nanoparticle. Nanoparticle formation was monitored by UV spectrophotometry at 420 nm wavelength and the silver nanoparticles were imaged by SEM. In the optimization study, it was found that at pH 5.0, 1.5 mM AgNO3 and 50% FCF containing medium was found to provide optimal conditions for the synthesis of the silver nanoparticle. The nanoparticles were spherical and varied between 15-35 nm.

The objective of this study is to determine the optimum parameters of electrocoagulation process in treatment of boron in low concentrations. Especially, studies on electrode optimization in low boron concentrated waters are insufficient. Therefore, the effect of electrode combination (Al–Al, Al–Fe, Al–SS, Fe–Al, Fe–Fe, and Fe–SS), pH (5–9), current density (8–24 mA cm −2 ), distance (1–3 cm), and electrolysis time (10–90 min) on treatment of boron containing wastewater is studied to obtain maximum removal efficiency. The maximum removal efficiency of boron is obtained as 95.6%. Operation conditions for maximum removal are the electrode combination of Fe–Al, current density of 16 mA cm −2 , pH 7.0, concentration of 30 mg L −1 and the reaction time of 70 min. Operating cost of the electrocoagulation process is calculated as 2.35 $ m −3 . This study indicates that the electrocoagulation process can be successfully applied in order to treat boron‐polluted wastewaters at low initial concentrations.

No abstract

Background: Formaldehyde (FA) is a carcinogen compound, which is soluble in water. FA can be removed from aqueous solution using advanced oxidation methods. Methods: In this study, the oxidation of FA was studied under fluorescent and UV light. Hydrogen peroxide (H2 O2 ) was used as an oxidant. The pH value and H2 O2 amount of samples were optimized. The chemical oxygen demand (COD), FA concentration, and H2 O2 consumption were followed. Results: It was observed that the pH value of the sample was more significant under fluorescent light than UV light at oxidation of FA. The highest COD removal and H2 O2 reduction were 18.57 and 30.90%, respectively, at pH 12.00, with a 1:1 ratio of FA:H2 O2 under fluorescent light. 86.41% FA and 62.12% COD removal were achieved at pH 7.00, with a 1:2 ratio of FA:H2 O2 , under UV light. It was observed that H2 O2 was consumed at all pH values under UV light. On the other hand, under fluorescent light, the concentration of H2 O2 decreased only at pH 12. In control samples containing only H2 O2 , the H2 O2 reduction was 92.09% at pH 11.91, while it was 2-6% at other pH levels under fluorescent light. The H2 O2 reduction changed between 33 and 44% at different pH values under UV light. The oxidation of FA was found to be suitable for the pseudo-first-order kinetic model and Langmuir isotherm model. Conclusion: The most effective oxidation was obtained at the original pH value (7.00) and 1:2 ratio of FA:H2 O2 under UV light.