Optimization of the Adsorption Condition for Wastewater Containing Chromium Treatment by Natural Adsorbent Material Using Response Surface Methodology

2014 ◽  
Vol 1033-1034 ◽  
pp. 387-390
Author(s):  
Ya Jun Wang ◽  
Jin Xi Wang ◽  
Yan Juan Li ◽  
Ying Wang

The effect of several important parameters on the removal of hexavalent chromium by humic acid was evaluated using an optimal experimental design based on Box-Behnken Response Surface method. The factors included temperature、pH、initial potassium chromate concentration and adsorbent dosage. A quadratic model for predicting the optimum removal conditions was derived, and the obtained optimal parameters were temperature 51°C, pH=2.34, initial potassium chromate concentration 14.30mg/L and adsorbent 0.58g. At the optimal conditions, the maximal removal rate of hexavalent chromium reached 73.17 %( forecast value was 73.26%).

2010 ◽  
Vol 8 (5) ◽  
pp. 1069-1077 ◽  
Author(s):  
Jalal Parsa ◽  
Mahmood Abbasi

AbstractThe nanocatalyst-assisted sonodegradation of Basic Blue 41 (BB41) dye in aqueous medium was modeled and optimized using response surface method (RSM) based on Box-Behnken design. The studied variables included pH, initial dye concentration, H2O2 concentration and sonolysis time while each factor varied at three levels: Low level (−1), Medium level (0) and High level (+1). The ultrasound -assisted degradation was well described by developing quadratic model with correlation value squared (R2) of 0.9114. Factor effects along with interaction effects were evaluated. The graphical optimization step was conducted to achieve the best experimental condition in dye removal. pH, H2O2 concentration and initial dye concentration of the reaction were investigated. It was recognized that at lower pH values the dye removal rate decreased. However, dye removal rate increased (82.5%) by increasing the concentration of H2O2 and by lowering the initial dye concentration.


2013 ◽  
Vol 295-298 ◽  
pp. 1258-1262
Author(s):  
Jun Sheng Hu ◽  
Lei Guan ◽  
Jia Li Dong ◽  
Ying Wang ◽  
Ying Yong Duan

Using electrochemical oxidation method treats the acid red 3R simulation wastewater, investigates the influence of current density, electrolyte concentration, pH-value and aeration and their interaction on the removal rate of chroma. Through the design of Box-Benhnken Design(BBD) and the response surface analysis, the influence sequence of all variables is current density > aeration > electrolyte concentration > pH-value, the influence sequence of all interaction is electrolyte concentration-aeration > current density-aeration ,electrolyte concentration-pH value > current density-pH value > pH value-aeration > current density-electrolyte concentration. Ultimately, the optimal value is 98.4915% under the condition of current density of 6.51mA/cm2,electrolyte concentration of 0.04mol/L,pH-value of 4.17 and aeration of 0.24m3/h.


Author(s):  
Yu Li ◽  
Leigang Li ◽  
Reham Yasser Farouk ◽  
Yuanyuan Wang

Flocculation can remove large amounts of nitrogen and phosphorus from wastewater, and the resulting nitrogen- and phosphorus-rich floc can be used to produce organic fertilizer. For biogas slurries containing high levels of nitrogen and phosphorus, ordinary flocculants can no longer meet the flocculation requirements. In this study, to fully utilize the advantages of the two flocculants and achieve efficient removal rates of nitrogen and phosphorus from a biogas slurry, chitosan (CTS) and polyaluminum chloride (PAC) were used as a composite flocculation agent to flocculate pig biogas slurries. The response surface method was used to study the effect of PAC added (PACadded) to the composite flocculant (CF), composite flocculant added (CFadded) to the biogas slurry and the pH on flocculation performance, and optimize these three parameters. In the tests, when the PACadded was 6.79 g·100 mL−1CF, the CFadded was 20.05 mL·L−1 biogas slurry and the pH was 7.50, the flocculation performance was the best, with an absorbance of 0.132 at a wavelength of 420 nm. The total phosphorus (TP) concentration was reduced from 214.10 mg·L−1 to 1.38 mg·L−1 for a removal rate of 99.4%. The total ammonia nitrogen (TAN) concentration was reduced from 1568.25 mg·L−1 to 150.27 mg·L−1 for a removal rate of 90.4%. The results showed that the CF could form larger flocs, and had greater adsorption capacity and more stable flocculation performance than ordinary flocculants. Furthermore, the CF could exhibit better chelation, electrical neutralization and bridge adsorption.


2018 ◽  
Vol 7 (3.1) ◽  
pp. 162 ◽  
Author(s):  
Ramanan. G ◽  
Rajesh Prabha.N ◽  
Diju Samuel.G ◽  
Jai Aultrin. K. S ◽  
M Ramachandran

This manuscript presents the influencing parameters of CNC turning conditions to get high removal rate and minimal response of surface roughness in turning of AA7075-TiC-MoS2 composite by response surface method. These composites are particularly suited for applications that require higher strength, dimensional stability and enhanced structural rigidity. Composite materials are engineered materials made from at least two or more constituent materials having different physical or chemical properties. In this work seventeen turning experiments were conducted using response surface methodology. The machining parameters cutting speed, feed rate, and depth of cut are varied with respect to different machining conditions for each run. The optimal parameters were predicted by RSM technique. Turning process is studied by response surface methodology design of experiment. The optimal parameters were predicted by RSM technique. The most influencing process parameter predicted from RSM techniques in cutting speed and depth of cut.   


2021 ◽  
Vol 39 (2A) ◽  
pp. 214-232
Author(s):  
Nuhad B. Dawood ◽  
Adnan A. AbdulRazak ◽  
Adel S. Hamadi

Nano emulsions (NEs) have important prospective advantages for assured industrials applications especially Metalworking fluids (MWFs), due to their Nano size, stability, than other types of traditional emulsions. In this work paraffin oil, water and mixture of surfactants Span20 & Tween20 are utilized for preparation of the MWF. A quadratic model was developed by applying the response surface method (RSM) to relate the droplets size and emulsion stability as a response to five independent variables namely the speed and time of mixing, concentration of the surfactant, Hydrophilic-Lipophilic Balance (HLB) value and pH value. Analysis of variance (ANOVA) was conducted; the results confirm the high significance of the regression model. The predicted values were found to be satisfactory with that experimental value. Mixing speed exerted the highest effect on the droplet size and the stability of the emulsion. The optimum conditions were found be (the concentration = 4.75 wt.%, time of mixing = 18.12 min, speed of mixing 14998.93 rpm, pH = 10.01 and HLB = 10.87) to attained Nano emulsion with 2 nm in size and stability of 24 days. Tool wear and surface roughness were studied at different speed, the results have showed that the wear ratio of the bits for all selected speeds is as follow: using commercial fluid > MWFs. The metallurgical microscope images have showed that, in case using MWFs the surface of cracks between the metals and the tool is more smooth compare with other fluids


2014 ◽  
Vol 12 (2) ◽  
pp. 164-172 ◽  
Author(s):  
Pengpeng Qiu ◽  
Mingcan Cui ◽  
Kyounglim Kang ◽  
Beomguk Park ◽  
Yonggyu Son ◽  
...  

AbstractA combined ultrasound (US)/H2O2 process was used to oxidize arsenite to arsenate, yielding a synergistic effect value of 1.26. This showed that the combined process could be an effective method of oxidizing arsenite, instead of using either ultrasonic or H2O2 oxidation processes. This combined process was successfully modeled and optimized using a Box-Behnken design with response surface methodology (RSM). The effects of the US power density, the initial concentration of arsenite, and the H2O2 concentration on the sonochemical oxidation efficiency of arsenite were investigated. Analysis of variance indicated that the proposed quadratic model successfully interpreted the experimental data with coefficients of determination of R 2 = 0.95 and adjusted R 2 = 0.91. Through this model, we can predict and control the oxidation efficiency under different conditions. Furthermore, the optimal conditions for the oxidation of arsenite were found to be a US power density of 233.26 W L−1, an initial arsenite concentration of 0.5 mg L−1, and an H2O2 concentration of 74.29 mg L−1. The predicted oxidation efficiency obtained from the RSM under the optimal conditions was 88.95%. A confirmation test of the optimal conditions verified the validity of the model, yielding an oxidation efficiency of 90.1%.


Catalysts ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 412 ◽  
Author(s):  
Yajun Li ◽  
Yongxiang Zhang ◽  
Qi Jing ◽  
Yuhui Lin

Nano zero-valent iron (NZVI) is widely used for reducing chlorinated organic pollutants in water. However, the stability of the particles will affect the removal rate of the contaminant. In order to enhance the stability of nano zero-valent iron (NZVI), the particles were modified with F-127 as an environmentally friendly organic stabilizer. The study investigated the effect of the F-127 mass ratio on the colloidal stability of NZVI. Results show that the sedimentation behavior of F-NZVI varied at different mass ratios. A biphasic model was used to describe the two time-dependent settling processes (rapid sedimentation followed by slower settling), and the settling rates were calculated. The surface morphology of the synthesized F-NZVI was observed with a scanning electron microscope (SEM), and the functional groups of the samples were analyzed with Fourier Transform Infrared Spectroscopy (FTIR). Results show that the F-127 was successfully coated on the surface of the NZVI, and that significantly improved the stability of NZVI. Finally, in order to optimize the removal rate of 2,4-dichlorophenol (2,4-DCP) by F-NZVI, three variables were tested: the initial concentration 2,4-DCP, the pH, and the F-NZVI dosage. These were evaluated with a Box-Behnken Design (BBD) of response surface methodology (RSM). The experiments were designed by Design Expert software, and the regression model of fitting quadratic model was established. The following optimum removal conditions were determined: pH = 5, 3.5 g·L−1 F-NZVI for 22.5 mg·L−1 of 2,4-DCP.


2015 ◽  
Vol 21 (1-1) ◽  
pp. 53-61 ◽  
Author(s):  
Vesna Tumbas-Saponjac ◽  
Gordana Cetkovic ◽  
Sladjana Stajcic ◽  
Jelena Vulic ◽  
Jasna Canadanovic-Brunet ◽  
...  

The production of high-quality freeze-dried raspberry was studied by response surface method. Two independent variables, temperature (X1) and time (X2) were determined as the most important factors affecting the final product quality estimated by the responses: total phenol (Y1), total anthocyanin (Y2), vitamin C (Y3) and total bioactive compounds (Y4) content. A two-factor central composite design was used for freeze-drying experiments. The second order polynomial models obtained were found to be significant (p<0.05) for all responses. The statistical analysis of experimental data indicated that only quadratic time variable (X22) had significant (p<0.05) effect on all responses. The optimal conditions for all responses combined were found to be: -31 ?C and 35 h. The experimental values of all responses obtained under optimal conditions were in good agreement with predicted values which enables the use of the proposed mathematical models for optimization of investigated process.


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