Catalytic Ozonation with ZnO Nanoparticles: A Novel Approach to Lignin Degradation in Synthetic Wastewater

Synthetic dye wastewater is a group of environmental pollutants that are widely used in some industries like textile, printing, dyeing and etc. Traditional treatment methods for wastewaters containing synthetic dyes are considered as expensive and time consuming approaches due to the chemical stability of these pollutants. Therefore, in recent years, biodegradation by means of capable microorganisms has been considered as an effective way to remove these pollutants. Hence, the present study has aimed at examining the decolorization of Toluidine Red (C.I. no.12120), which is an oil soluble azo dye, as the sole sources of carbon and energy from a synthetic dye wastewater by the halophilic Halomonas strain Gb bacterium. In order to model, optimize, and investigate the individual factors affecting the biodegradation capacity of this dye by Halomonas strain Gb, for the first time response surface methodology (RSM) and central composite design (CCD) were applied. In this research, statistical modeling and optimization were performed by Design Expert software version 10 and the degradation capacity was considered by carrying out 30 tests using RSM method. For this purpose, the effect of 4 variables included dye concentration (10-30ppm), salt concentration (2-10%), pH (5.5-9.5), and temperature (20-40) at different times of 2nd, 4th, and 10th days have been studied. Then, a second-order function was presented for the amount of dye removal in terms of the four selected variables, based on statistical modeling. According to the obtained results and analysis of variance, all main variables were found to be significantly effective on the biodegradation capacity. With regard to the results, the highest amount of biodegradation between different days was 81% and observed at the 4th day, while the optimum conditions for the maximum biodegradation of this time has been determined at pH of 6.5, temperature of 35°C, and salt and dye concentrations were equivalent to 4% and 25ppm, respectively. There is 11% relative error between the experimental and predicted results in the selected experiments, which confirms the reliability of the obtained correlation for calculating the decolorization capacity. In accordance with the results, the proposed model can provide a good prediction of the effect of different conditions on the biodegradation of Toluidine Red, and the optimization results in this study have been consistent with the previous studies conducted with the IP8 and D2 strains by the OFAT method. Moreover, the proposed model may help in better understanding the impact of main effects and interaction between variables on the dye removal. Overall, the results indicated that the halophilic bacterium used in dye removal can be more effective in high-salinity environments.

Produced water is wastewater from oil production that must be treated well. Membrane is one alternative to water treatment technology based on filtration method. But, in the use of a membrane, there’s no exact variable optimal that influences performance of the membrane. This underlying research to assess factors that influences the performance of membrane to be more optimal. Therefore, the objectives of this study determine the optimum variable through Respond Surface Methodology and Central Composite Design. After getting the optimal condition then will check the stability of the membrane. This experiment of optimization of produced water with asymmetric membrane's Polyether sulfone (PES) using Response Surface is done with varying the Zeolite concentration by low level 1% weight and 3% weight, length of UV irradiation time low level 2 minutes and high level 6 minutes, thermal annealing low level 160 ºC and high-level 180ºC. An analyzer done in this research was by processing data research to make table and charts of the relationship between the result of this experiment with changed variable, namely variation of PES concentration, time of UV ray and thermal annealing by using Response Surface Methodology (RSM) and Central Composite Design (CCD).

A Response Surface Methodology (RSM) was employed to optimize the Microwave-Assisted Extraction (MAE) of polyphenolics from rambutan (Nephelium Lappaceum L.) peels, with three key factors, involving ethanol concentration (X1), extraction time (X2), and material-to-solvent ratio (X3). These factors were initially examined using single-factor analysis, while a central composite design on three levels was subsequently used for optimization. The experimental results were fitted to a second-order polynomial model, and an Analysis Of Variance (ANOVA) was conducted to assess the significance of each factor on the extraction process. Considering the maximum extracted Total Phenolic Content (TPC), Total Flavonoid Content (TFC), and Antioxidant Activity (AA), the optimal conditions (X1, X2, X3) for each response were (42%, 132 s, 0.002 g mL-1), (46%, 133 s, 0.002 g mL-1), and (40%, 121 s, 0.002 g mL-1), respectively. Under the optimal conditions, the rambutan peel extract yielded 225.6 ± 6.6 mg-GAE/g (TPC), 179.7 ± 9.2 mg-RE/g (TFC), and 149.3 ± 2.1 mmol-TE/g (AA).

PurposeThe aim of this study is evaluation of the perchloroethylene degradation from aqueous solutions by non-thermal plasma produced in dielectric barrier discharge reactor in two different scenarios: first plasma generated with 225 cc/min mixture of oxygen and argon flow (12% gas ratio of O2/Ar), and in the second scenario plasma generated with 225 cc/min of pure argon gas.MethodsDesign studies were performed using response surface methodology and central composite design. All experiments with the selected levels of independent parameters including the initial concentration of perchloroethylene (5–100 mg/L), voltage (20–5 kv) and contact time (15–180 s) was implemented, and 29 tests were proposed by using response surface methodology and central composite design was performed in two experimental scenarios.ResultsResults showed that the Pseudo first-order kinetics coefficient of perchloroethylene degradation in the mixture of oxygen and argon and pure argon scenario under the optimum conditions were 0.024 and 0.016 S−1 respectively. Results conveyed that in order to achieve the highest removal efficiency (100%), the values of contact time, perchloroethylene concentration and voltage variables were predicted 169.55 s, 74.3 mg/l, 18.86 kv respectively in mixture of oxygen and argon scenario and also were predicted 203 s, 85.22 mg/l, 20.39 kv respectively in pure argon scenario.ConclusionsIn the recent study dielectric barrier discharge was an efficient method for perchloroethylene removal with both oxygen an argon mixture and pure argon as input gas. Both input voltage and reaction time has positive effect on perchloroethylene removal; but initial perchloroethylene concentration has negative effect on perchloroethylene removal. Comparison of two plasma scenarios with different input gas shown that plasma generated by mixture of oxygen and argon gas was more powerful and had higher removal efficiency and degradation kinetics than the plasma generated by pure argon gas.

Optimization of ultrasound-assisted extraction of phenols from Crocus sativus by-products using sunflower oil as a sustainable solvent alternative

The prevalence of urolithiasis has become a concerning issue in Malaysia. Its treatment normally relies on medical processes which are costly and can trigger reoccurrence. Traditional healers have used Aquilaria malaccensis (agarwood) to treat urolithiasis; however, the extraction parameters that result in optimum effectiveness have not been determined. Hence, this research aims to optimise the extraction parameters of A. malaccensis stem on in vitro antiurolithiatic activities by applying response surface methodology (RSM) and central composite design (CCD). The studied parameters were solvent concentration (X1), extraction temperature (X2) and extraction time (X3). Their effects on antiurolithiatic activities (turbidity assay, Y1; titrimetric assay, Y2) were also investigated. The presence of phenols, alkaloids and terpenoids was assessed both qualitatively and quantitatively. The quadratic model was selected for both antiurolithiatic activities as the R2 values achieved were close to 1 and were significantly affected by each studied parameter (p < 0.05). The optimum extraction condition of A. malaccensis stem extract was 100% ethanol, 30.0°C extraction temperature and 30 min extraction time. The extract demonstrated antiurolithiatic activities measured at 83.58 ± 0.75% (turbidity assay) and 86.57 ± 0.80% (titrimetric assay). The phytoconstituents in A. malaccensis stem extracts showed positive correlations with both antiurolithiatic activities. This research has established the reliability of RSM to optimise extraction conditions of A. malaccensis stem to exhibit high antiurolithiatic activities.

Evsel katı atıklarınbertarafında düzenli depolama yöntemi sıklıkla tercih edilmektedir. Çok kirlisızıntı suyu oluşumu, düzenli depolama tesislerinin en önemli dezavantajıdır.Bu çalışmada, Cevap Yüzey Yöntemi ve Merkezi Kompozit Tasarımı kullanılaraksızıntı suyundan amonyum giderimine yönelik strüvit çöktürme optimizasyonuyapılmıştır. Optimum strüvit çöktürme şartlarının belirlenmesi için 11 adetdeneysel çalışma yapılmıştır. Sonuçlar ikinci dereceden polinom fonksiyonelmodel ile iyi uyum göstermiştir. İstatistiki analizler, Mg/N ve N/P molar oranıbağımsız değişkenlerinin amonyum giderim verimi üzerine önemli etkisininolduğunu ortaya koymuştur. En yüksek amonyum giderim verimine %99,8 olarak; 9,2sabit pH değerinde, Mg/N için 1,2 ve N/P için 1,27 molar oranlarındaulaşılmıştır. Elde edilen sonuçlar, anaerobik proseste ön arıtım olarakkullanılan strüvitin Cevap Yüzey Yöntemi kullanılarak modellenebildiğini ortayakoymuştur. Ayrıca Cevap Yüzey Yöntemi; KOİ/N/P için 300:5:1 oranına sahip biranaerobik proses için tasarlanmış olan ön arıtım performansını etkileyen dahadüşük Mg/N ve N/P molar oranı için gerekli amonyum giderme verimliliğinioptimize etmek için kullanılabilir.

The aim of this work was to improve the ability of electro-Fenton technique for the remediation of wastewater contaminated with synthetic dyes using a model azo dye such as Azure B. Batch experiments were conducted to study the effects of main parameters, such as dye concentration, electrode surface area, treatment time, and voltage. In this study, central composite face-centered experimental design matrix and response surface methodology were applied to design the experiments and evaluate the interactive effects of the four studied parameters. A total of 30 experimental runs were set, and the kinetic data were analyzed using first- and second-order models. The experimental data fitted to the empirical second-order model of a suitable degree for the maximum decolorization of Azure B by electro-Fenton treatment. ANOVA analysis showed high coefficient of determination value (R(2) = 0.9835) and reasonable second-order regression prediction. Pareto analysis suggests that the variables, time, and voltage produce the largest effect on the decolorization rate. Optimum conditions suggested by the second-order polynomial regression model for attaining maximum decolorization were dye concentration 4.83 mg/L, electrode surface area 15 cm(2), voltage 14.19 V, and treatment time of 34.58 min.

This study aims to analyze sodium azide removal from medical laboratory wastewater by using Electro-Fenton (EF) and ozonation methods and to determine the optimum process conditions. Under optimum conditions; 98.9% and 99.6% sodium azide removal efficiency was obtained through EF and ozonation processes, respectively. This is the first and the only optimization study in literature in which response surface methodology and central composite design were used for sodium azide removal from wastewater. Results of the study indicated that EF and ozonation processes are effective methods for sodium azide removal, and central composite design is a suitable tool for process optimization.

Degradation of humic substances in water is important due to its adverse effects on the environment and human health. The aim of this study was modeling and investigating the degradation of humic substances in water using immobilized ZnO as a catalyst. ZnO nanoparticles were synthesized through simple coprecipitation (CPT) method and immobilized on glass plates. The immobilized ZnO nanocatalyst was characterized through scanning electron microscopy (SEM) and X-ray diffraction (XRD). Response surface methodology (RSM) and central composite design (CCD) were used to create an experimental design for humic degradation and color removal efficiency. The most important parameters including initial concentration, pH, and contact time were optimized. The optimum conditions were initial concentration of 7.68 mg/l, pH of 4.42, and contact time of about 125.6 minutes. Under optimal conditions, maximum humic substances and color removal of about 100 and 82.37% were obtained, respectively. These results illustrate that an immobilized form of ZnO can be used as an efficient nanocatalyst for effective degradation of humic substances in water.

Optimized Electrodeposition Concentrations for Hydroxyapatite Coatings on CoCrMo biomedical alloys by computational techniques

A rapid and sensitive dispersive liquid-liquid microextraction (DLLME) has been developed for the extraction of selected polycyclic aromatic hydrocarbons (PAHs), namely phenanthrene (PHE) and fluoranthene (FLA) in green tea beverage samples. The extracted PAHs were separated and determined by using high-performance liquid chromatography diode array detection (HPLC-DAD). An experimental design using response surface methodology (RSM) and central composite design (CCD) was performed to evaluate the interactive effects of the 2 most significant parameters, namely extraction time and sample pH. The optimal conditions were sample pH of 6.5 with 1.25 min extraction time. The analysis of variance (ANOVA) showed that the most influential parameter was the extraction time. The predicted values were obtained in good agreement with the actual value (R2 ≥ 0.9086). Under the optimal extraction conditions, the method demonstrated acceptable linearity (R2 ≥ 0.9996) over a concentration range (10 - 1,000 µg L−1) for different PAHs. The limits of detection and quantifications were in the range of (4 - 10 µg L−1) and (18 - 50 µg L−1), respectively. Good analytes recovery (102 - 110 %) and excellent precision level with relative standard deviations (RSD %, n = 3) were obtained between 1.53 and 4.52 %. The method was successfully applied to the analysis of spiked green tea beverage samples. The proposed method is rapid, reliable, sensitive, and environmentally friendly for the detection of PAHs.
 HIGHLIGHTS
 
 A more efficient sample preparation method is required to measure interferences and enrich target analysis of PAHs residues in green tea, as existing methods are time-consuming, significant tendency to form emulsions, consume large volumes of solvents, and involve disposal of toxic or flammable chemicals
 Dispersive liquid-liquid microextraction (DLLME) method coupled with a high-performance liquid chromatography diode array detector (HPLC-DAD) was developed for the analysis of selective PAHs, namely fluoranthene (FLA) and phenanthrene (PHE) in green tea beverage samples
 RSM optimized DLLME parameters based on CCD, and the optimal conditions used during the analysis of PHE and FLA in the green tea samples extracted the non-polar PHE and FLA with good sensitivity. The procedure was simple, rapid, sensitive, and minimized the consumption of organic solvent
 
 GRAPHICAL ABSTRACT

Response surface methodology and central composite design were used to optimize a biosynthesis medium for the production of xylanases by Streptomyces sp. P12-137 in submerged fermentation culture at pH 5.0, with wheat bran as substrate. The three variables involved in this research were the wheat bran, potassium nitrate and xylose concentrations. Statistical analysis of the results showed that, in the range studied, xylose and potassium nitrate concentrations had a significant effect on xylanase production. The optimized biosynthesis medium contained (in %, w/v): wheat bran 1.0, KNO3 1.0, xylose 0.5. This medium resulted in a 3-fold increased level of the xylanase (27.77 UA/ml) production compared to the initial level (8.30 UA/ml) after 120 h of fermentation, whereas the value predicted by the quadratic model was 26.45 UA/ml.

The aim of this work was to improve the ability of the electro-Fenton process using Fe alginate gel beads for the remediation of wastewater contaminated with synthetic dyes and using a model diazo dye such as Reactive Black 5 (RB5). Batch experiments were conducted to study the effects of main parameters, such as voltage, pH and iron concentration. Dye decolourisation, reduction of chemical oxygen demand (COD) and energy consumption were studied. Central composite face-centred experimental design matrix and response surface methodology were applied to design the experiments and to evaluate the interactive effects of the three studied parameters. A total of 20 experimental runs were set, and the kinetic data were analysed using first-order and second-order models. In all cases, the experimental data were fitted to the empirical second-order model with a suitable degree for the maximum decolourisation of RB5, COD reduction and energy consumption by electro-Fenton-Fe alginate gel beads treatment. Working with the obtained empirical model, the optimisation of the process was carried out. The second-order polynomial regression model suggests that the optimum conditions for attaining maximum decolourisation, COD reduction and energy consumption are voltage, 5.69 V; pH 2.24 and iron concentration, 2.68 mM. Moreover, the fixation of iron on alginate beads suggests that the degradation process can be developed under this electro-Fenton process in repeated batches and in a continuous mode.

Shortages and lack of sources of clean water is a big issue nowadays. This problem happens because of the increment of population that leads to the amount of water usage increases at an alarming rate. Therefore, the sources of water must be explored in order to get a continuous supply of clean water. This paper recommends a new approach to get clean water, which is by purifying the stormwater via progressive freeze concentration (PFC). This method produces a single ice crystal block that contains high purity of water. This paper focuses on the optimization of two operating parameters, which are coolant temperature and operating time. In order to determine the effectiveness of this technology, effective partition constant (K) and concentration efficiency (Eff) were examined. Response surface methodology and central composite design were implemented to find the optimum operating conditions via Statistica software. The best responses for K and Eff obtained were 0.189 and 81.0%, respectively, with the optimum condition at coolant temperature of −8.9°C and operating time at 41.1 min. From the findings, it is proved that PFC has the capability to reduce the concentration of unwanted solute in stormwater and this process has a high potential to be an alternative approach to purify the stormwater.