Evaluation of Ammonia-Nitrogen Removal by Ultrasonic Irradiation in Synthetic Solution Using Response Surface Methodology

2019 ◽  
Vol 797 ◽  
pp. 108-117
Author(s):  
Khadijah Mohamad Aris ◽  
Suzana Ramli ◽  
Zulhafizal Othman ◽  
Jurina Jaafar

The objective of this study was to evaluate the ability of ultrasonic irradiation to remove ammonia-nitrogen in synthetic solution by considering the factors including initial concentration, pH and irradiation time. Ultrasonic bath was used to provide a constant effective power, frequency and temperature of 150 W, 37 kHz and 60°C, respectively during sonication. It was revealed that the removal efficiency of ammonia-nitrogen improved at lower concentration with basic water environment and extended irradiation time. Based on this judgement, optimization is carried out by using response surface methodology (RSM) of Box Behnken design to develop a quadratic regression model in order to analyze the interactions between the three factors and their effects on the removal efficiency. Optimum removal achieved from the model was found to be 82.26% at 10 mg/L of initial concentration with pH of 11 and sonication for 30 minutes. Verification of the quadratic regression model is done by comparing with the experimental work conducted within the experimental domain.

2012 ◽  
Vol 610-613 ◽  
pp. 3387-3393
Author(s):  
Xiao Bing Huang ◽  
Li Jing Lin ◽  
Ji Hua Li ◽  
Xu Ran ◽  
Yong Fu Tang

Optimization conditions for ultrasonic extraction of phenolics from litchi seed were studied using response surface methodology. A Box–Behnken design (BBD) was applied to determine the effects of extraction temperature, methanol concentration and extraction time on yield of phenolics. Then a quadratic regression model was developed and found to be statistically significant by examining its adequacy. According to the model, the maximum yield of phenolics was obtained at the theoretical extraction conditions described as follows: extraction temperature 90°C, methanol concentration 59% and extraction time 70 min. Under this condition, the experimental value was 5.48 ± 0.03% (n = 3) with gallic acid as the equivalent, which agreed with the predicted value (5.52%) closely.


2018 ◽  
Vol 16 (1) ◽  
pp. 1283-1296 ◽  
Author(s):  
Shoujian Song ◽  
Changchun Hao ◽  
Xianggang Zhang ◽  
Qing Zhang ◽  
Runguang Sun

AbstractIn the present study, the Fe-doped TiO2 modified nanoparticles was successfully synthesized by the combination of the sol-gel method and heat treatment, and the degradation of methyl orange was tested by the combination method of ultrasonic radiation and mechanical agitation. The effects of different factors on the degradation of methyl orange (MO) solution were studied, such as ultrasonic irradiation time, the ultrasonic frequency, the added amount of catalyst, the initial pH value, the initial concentration of methyl orange, and revolutions per minute. The optimal experimental conditions for sonocatalytic degradation of the MO obtained were: ultrasonic irradiation time = 60 min, pH value = 3.0 and revolutions per minute = 500 rpm. By means of response surface analysis, the best fitting conditions were as follows: ultrasonic frequency = 36.02 kHz, added amount of catalyst = 490.50 mg/L, the initial concentration of methyl orange = 9.22 mg/L, and the optimum condition was close to the experimental data by response surface method. Under optimal conditions, the sonocatalytic degradation of MO was 99%. The degradation of MO showed that the combination of Fe-doped modified TiO2 nanoparticles, mechanical agitation and ultrasonic irradiation was discovered that can degrade methyl orange effectively in aqueous solution.


Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 1093 ◽  
Author(s):  
Songtao Shen ◽  
Qing Wang ◽  
Jiancheng Shu ◽  
Li Ma ◽  
Li Chen ◽  
...  

For optimizing the reaction conditions of 2-methyl-6-ethylaniline (MEA) degradation catalyzed by horseradish peroxidase (HRP), a response surface methodology with three factors and three levels was used in this research to establish a regression model, a ternary quadratic polynomial, in order to analyze temperature, H2O2 concentration and pH effects on MEA removal efficiency. The results showed that the regression model was significant (p < 0.0001), fitted well with experimental data and had a high degree of reliability and accuracy, and the data were reasonable with low errors. By analyzing interactions and solving the regression model, the maximum MEA removal efficiency was 97.90%, and the optimal conditions were defined as follows: pH 5.02, H2O2 concentration 13.41mM, and temperature 30.95 °C. Under the optimal conditions, the average MEA removal efficiency obtained from the experiments was 97.56%. This research can provide reference for the treatment of actual acetochlor industrial wastewater.


2017 ◽  
Vol 19 (2) ◽  
pp. 232-240 ◽  

Removal of Mo(VI) from aqueous solutions by using bentonite and powdered cockle shell was conducted in this research. First, the effects of pH and initial Mo(VI) concentration on the Mo removal efficiency via shell and bentonite were studied. Results showed that Mo removal effectiveness increased as pH increased until 3.5. Removal efficiency of Mo via bentonite and shell also increased as initial Mo(VI) concentration increased to 30 or 40 mg/L, respectively, after which the removal efficiency decreased. Response surface methodology and central composite design were applied to optimize removal effectiveness. Initial concentration of Mo(VI) (mg/L), pH, and shaking time (min) were selected as independent factors. These results showed that bentonite is more effective in removing Mo from water than the shell. At the optimum condition of 5.8 pH, initial Mo concentration of 39.2 mg/L, and shaking time of 38.6 min, bentonite could remove 81.3% of Mo.


Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3150
Author(s):  
Mengwei Xu ◽  
Chao Huang ◽  
Jing Lu ◽  
Zihan Wu ◽  
Xianxin Zhu ◽  
...  

Magnetic MXene composite Fe3O4@Ti3C2 was successfully prepared and employed as 17α-ethinylestradiol (EE2) adsorbent from water solution. The response surface methodology was employed to investigate the interactive effects of adsorption parameters (adsorption time, pH of the solution, initial concentration, and the adsorbent dose) and optimize these parameters for obtaining maximum adsorption efficiency of EE2. The significance of independent variables and their interactions were tested by the analysis of variance (ANOVA) and t-test statistics. Optimization of the process variables for maximum adsorption of EE2 by Fe3O4@Ti3C2 was performed using the quadratic model. The model predicted maximum adsorption of 97.08% under the optimum conditions of the independent variables (adsorption time 6.7 h, pH of the solution 6.4, initial EE2 concentration 0.98 mg L−1, and the adsorbent dose 88.9 mg L−1) was very close to the experimental value (95.34%). pH showed the highest level of significance with the percent contribution (63.86%) as compared to other factors. The interactive influences of pH and initial concentration on EE2 adsorption efficiency were significant (p < 0.05). The goodness of fit of the model was checked by the coefficient of determination (R2) between the experimental and predicted values of the response variable. The response surface methodology successfully reflects the impact of various factors and optimized the process variables for EE2 adsorption. The kinetic adsorption data for EE2 fitted well with a pseudo-second-order model, while the equilibrium data followed Langmuir isotherms. Thermodynamic analysis indicated that the adsorption was a spontaneous and endothermic process. Therefore, Fe3O4@Ti3C2 composite present the outstanding capacity to be employed in the remediation of EE2 contaminated wastewaters.


2015 ◽  
Vol 4 (4) ◽  
Author(s):  
Seyed Mohammad Safieddin Ardebili ◽  
Teymor Tavakoli Hashjin ◽  
Barat Ghobadian ◽  
Gholamhasan Najafi ◽  
Stefano Mantegna ◽  
...  

AbstractThis work investigates the effect of simultaneous ultrasound-microwave irradiation on palm oil transesterification and uncovers optimal operating conditions. Response surface methodology (RSM) has been used to analyze the influence of reaction conditions, including methanol/palm oil molar ratio, catalyst concentration, reaction temperature and irradiation time on biodiesel yield. RSM analyses indicate 136 s and 129 s as the optimal sonication and microwave irradiation times, respectively. Optimized parameters for full conversion (97.53%) are 1.09% catalyst concentration and a 7:3.1 methanol/oil molar ratio at 58.4°C. Simultaneous ultrasound-microwave irradiation dramatically accelerates the palm oil transesterification reaction. Pure biodiesel was obtained after only 2.2 min while the conventional method requires about 1 h.


2017 ◽  
Vol 76 (4) ◽  
pp. 776-784 ◽  
Author(s):  
Mijia Zhu ◽  
Jun Yao ◽  
Zhonghai Qin ◽  
Luning Lian ◽  
Chi Zhang

Wastewater produced from polymer flooding in oil production features high viscosity and chemical oxygen demand because of the residue of high-concentration polymer hydrolysed polyacrylamide (HPAM). In this study, steel slag, a waste from steel manufacturing, was studied as a low-cost adsorbent for HPAM in wastewater. Optimisation of HPAM adsorption by steel slag was performed with a central composite design under response surface methodology (RSM). Results showed that the maximum removal efficiency of 89.31% was obtained at an adsorbent dosage of 105.2 g/L, contact time of 95.4 min and pH of 5.6. These data were strongly correlated with the experimental values of the RSM model. Single and interactive effect analysis showed that HPAM removal efficiency increased with increasing adsorbent dosage and contact time. Efficiency increased when pH was increased from 2.6 to 5.6 and subsequently decreased from 5.6 to 9.3. It was observed that removal efficiency significantly increased (from 0% to 86.1%) at the initial stage (from 0 min to 60 min) and increased gradually after 60 min with an adsorbent dosage of 105.2 g/L, pH of 5.6. The adsorption kinetics was well correlated with the pseudo-second-order equation. Removal of HPAM from the studied water samples indicated that steel slag can be utilised for the pre-treatment of polymer-flooding wastewater.


2016 ◽  
Vol 74 (3) ◽  
pp. 564-579 ◽  
Author(s):  
Ceyhun Akarsu ◽  
Yasin Ozay ◽  
Nadir Dizge ◽  
H. Elif Gulsen ◽  
Hasan Ates ◽  
...  

Marine pollution has been considered an increasing problem because of the increase in sea transportation day by day. Therefore, a large volume of bilge water which contains petroleum, oil and hydrocarbons in high concentrations is generated from all types of ships. In this study, treatment of bilge water by electrocoagulation/electroflotation and nanofiltration integrated process is investigated as a function of voltage, time, and initial pH with aluminum electrode as both anode and cathode. Moreover, a commercial NF270 flat-sheet membrane was also used for further purification. Box–Behnken design combined with response surface methodology was used to study the response pattern and determine the optimum conditions for maximum chemical oxygen demand (COD) removal and minimum metal ion contents of bilge water. Three independent variables, namely voltage (5–15 V), initial pH (4.5–8.0) and time (30–90 min) were transformed to coded values. The COD removal percent, UV absorbance at 254 nm, pH value (after treatment), and concentration of metal ions (Ti, As, Cu, Cr, Zn, Sr, Mo) were obtained as responses. Analysis of variance results showed that all the models were significant except for Zn (P &gt; 0.05), because the calculated F values for these models were less than the critical F value for the considered probability (P = 0.05). The obtained R2 and Radj2 values signified the correlation between the experimental data and predicted responses: except for the model of Zn concentration after treatment, the high R2 values showed the goodness of fit of the model. While the increase in the applied voltage showed negative effects, the increases in time and pH showed a positive effect on COD removal efficiency; also the most effective linear term was found as time. A positive sign of the interactive coefficients of the voltage–time and pH–time systems indicated synergistic effect on COD removal efficiency, whereas interaction between voltage and pH showed an antagonistic effect.


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