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central composite design for optimization and formulation of desulphurization of iron ore concentrate using atmospheric leaching process

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Journal of Iron and Steel Research International 2018年第1期25卷 57-64页

作者： Ali Mostafavi Hassan Rezvanipour Dariush Afzali Tayebeh Shamspur Amir Hajizadehomran Department of Chemistry Shahid Bahonar Universityof Kerman Kerman 84156-83111 Iran Gol-e-Gohar Iron Ore Mining and Industrial Company Sirjan Km 50 of Shiraz road 111/78185 Kerman Iran Department of Environment Institute of Science and HighTechnology and Environmental Sciences GraduateUniversity of Advanced Technology Kerman 76311-33131Iran

Owing to the negative effects of sulphur in iron ore on steelmaking process and environment, a tank leaching process was performed in atmospheric conditions to remove the sulphur from the iron ore concentrate and simultaneously to transform sulphide minerals into useful by-products. To achieve desirable sulphur removal rate and efficiency, central composite design was adopted as a response surface methodology for the optimization and evaluation of the process. A full-quadratic polynomial equation between the sulphur removal and the studied parameters was established to assess the behaviour of sulphur removal as a function of the factors and to predict the results in various conditions. The optimum conditions were obtained based on the variance tests and response surface plots, from which the optimized ranges for each factor resulting in the best response （corresponding to the highest percentage of desulphurization） could be then achieved. The results show that most desirable conditions are atmospheric leaching in 1.39 mol/dm3 nitric acid and 0.88 mol/dm3 sulphuric acid for 47 h. The designed process under the optimized desulphurization conditions was applied to a real iron ore concentrate. More than 75% of the total sulphur was removed via the leaching process. In addition to the desulphurization, the conversion of sulphide-bearing minerals into useful by-products, extraction of valuable metals, and executing the process under atmospheric conditions are the other advantages of the proposed method.

关键词： Desulphurization Iron ore concentrate Sulphide mineral leaching central composite design Atmosphericleaching process

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Degradation of refractory organics in concentrated leachate by the Fenton process: central composite design for process optimization

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Frontiers of Environmental Science & Engineering 2021年第1期15卷 47-62页

作者： Senem Yazici Guvenc Gamze Varank Department of Environmental Engineering Yildiz Technical UniversityDavutpasa CampusEsenlerIstanbul 34220Turkey

The primary aim of this study is inert COD removal from leachate nanofiltration concentrate because of its high concentration of resistant organic *** this framework,this study focuses on the treatability of leachate nanofiltration concentrate through Fenton oxidation and optimization of process parameters to reach the maximum pollutant removal by using response surface methodology(RSM).Initial pH,Fe2+concentration,H_(2)O_(2)/Fe^(2+)molar ratio and oxidation time are selected as the independent variables,whereas total COD,color,inert COD and UV254 removal are selected as the *** to the ANOVA results,the R^(2) values of all responses are found to be over 95%.Under the optimum conditions determined by the model(pH:3.99,Fe^(2+):150 mmol/L,H_(2)O_(2)/Fe^(2+):3.27 and oxidation time:84.8 min),the maximum COD removal efficiency is determined as 91.4%by the *** color,inert COD and UV254 removal efficiencies are determined to be 99.9%,97.2%and 99.5%,respectively,by the model,whereas the total COD,color,inert COD and UV254 removal efficiencies are found respectively to be 90%,96.5%,95.3%and 97.2%,experimentally under the optimum operating *** Fenton process improves the biodegradability of the leachate NF concentrate,increasing the BOD5/COD ratio from the value of 0.04 to the value of *** operational cost of the process is calculated to be 0.238€/g COD_(removed).The results indicate that the Fenton oxidation process is an efficient and economical technology in improvement of the biological degradability of leachate nanofiltration concentrate and in removal of resistant organic pollutants.

关键词： Concentrated leachate Fenton oxidation central composite design Biodegradability Inert COD

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Optimization of micellar electrokinetic capillary chromatography method using central composite design for the analysis of components in Yangwei granule

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2011年第3期12卷 193-200页

作者： Shu-fang WANG Hai-yan FANG Hai-bin QU Pharmaceutical Informatics Institute Zhejiang University Hangzhou 310058 China

central composite design(CCD),together with multiple linear regression,was successfully used to optimize the electrophoretic buffer system of micellar electrokinetic capillary chromatography(MEKC) for the determination of albiflorin,paeoniflorin,liquiritin,and glycyrrhizic acid in the traditional Chinese medicine(TCM) prescription,Yangwei *** of sodium deoxycholate(SDC) and borate,and proportions of ammonia,acetonitrile,and methanol were *** total resolutions of peaks between the analytes and their adjacent peaks in real samples were integrated into the evaluation index of separation *** optimum electrophoretic buffer contained 80 mmol/L SDC,20 mmol/L borate,5%(v/v) methanol,0.5%(v/v) ammonia,and 5%(v/v) *** correlation coefficients(R 2 ) between the peak areas and the corresponding concentrations of analytes were greater than *** limits of detection(LODs) (S/N=3) of the analytes were 0.97-4.00μg/*** results indicate the superiority of CCD in optimizing the separation conditions of complex samples such as TCM prescriptions.

关键词： Micellar electrokinetic capillary chromatography Traditional Chinese medicine central composite design Yangwei granule

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Optimization of compression formulation and load of food-grade tracers for grain traceability using central composite design

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International Journal of Agricultural and Biological Engineering 2017年第6期10卷 221-230页

作者： Liang Kun Zhang Lingling Lu Wei Cedric Sean Okinda Shen Mingxia College of Engineering/Key Laboratory of Intelligent Equipment for Agriculture of Jiangsu Province Nanjing Agricultural UniversityNanjing 210031China

Food-grade tracers have been developed as an identification technology for grain traceability from original harvest to final destination for *** characteristics of food-grade tracers must be able to satisfy the environmental demands for grain *** optimize the food-grade tracer production process,the effects of direct compression formulation and load on the mechanical characteristics were studied using response surface methodology(RSM)with central composite design(CCD).Among the four tested formulations,Formulations#2(consisting of 35.00%lactose 100 mesh,64.50%microcrystalline cellulose 102 and 0.50%magnesium stearate)and#4(consisting of 38.00%lactose 100 mesh,50.00%microcrystalline cellulose 102,11.00%pregelatinized starch and 1.00%magnesium stearate)were selected for tracer production based on their physical properties as *** value of Carr’s flowability index was 68 for both Formulations#2 and#4,which was the highest among all the ***,Formulations#2 and#4 also had the best powder *** magnesium stearate ratio(1.00%-3.00%)and pressure(6.00-16.00 kgf)were used as independent variables to detect changes in the breaking rate,peak shear force and friction coefficient of tracers compressed by the selected *** optimal production parameters could be achieved at a magnesium stearate ratio of 2.25%and pressure of 16.00 kgf for Formulation#2 and at a magnesium stearate ratio of 1.02%and pressure of 16.00 kgf for Formulation#*** these optimal conditions,the tracers had good impact characteristics(breaking rate),compression characteristics(peak shear force)and frictional characteristics(friction coefficient).Moreover,Formulation#2 was more suitable for production because compared to Formulation#4,its breaking rate and friction coefficient values were lower,and its peak shear force value was higher.

关键词： grain traceability food-grade tracer optimization food safety formulation mechanical property central composite design

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Modeling and Optimization of Catalytic Dehydration of Ethanol to Ethylene Using central composite design

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Transactions of Tianjin University 2009年第5期15卷 366-370页

作者：孔海宁齐二石李钢何曙光张宪 School of Management Tianjin University School of Chemical Engineering and Technology Tianjin University

The central composite design in the modeling and optimization of catalytic dehydration of ethanol to ethylene was performed to improve the ethylene yield.A total of 20 experiments at random were conducted to investigate the effect of reaction temperature,Si/Al ratios of H-ZSM-5 catalyst and liquid hourly space velocity(LHSV) on the ethylene *** results show that the relationship between ethylene yield and the three significant independent variables can be approximated by a nonlinear polynomial model,with R-squared of 99.9%and adjusted R-squared of 99.8%.The maximal response for ethylene yield is 93.4%under the optimal condition of 328 ℃,Si/Al ratio 85,and LHSV 3.8 h-1.

关键词： central composite design catalytic dehydration of ethanol ethylene yield modeling optimization

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Enhanced production of thermostable laccases from a native strain of Pycnoporus sanguineus using central composite design

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2014年第4期15卷 343-352页

作者： Leticia I. RAMíREZ-CAVAZOS Charles JUNGHANNS Rakesh NAIR Diana L. CáRDENAS-CHáVEZ Carlos HERNáNDEZ-LUNA Spiros N. AGATHOS Roberto PARRA Centro del Agua para América Latina y el Caribe Tecnológico de MonterreyCampus MonterreyNL 64849Mexico Helmholtz Centre for Environmental Research-UFZ Permoserstra?e 1504318 LeipzigGermany Bioengineering Group Earth and Life InstituteUniversité Catholique de LouvainPlace Croix du Sud2Box L7.05.191348 Louvain-la-NeuveBelgium Laboratorio de Enzimología Facultad de Ciencias BiológicasUniversidad Autónoma de Nuevo LeónAv. Universidad s/nCiudad UniversitariaSan Nicolás de los GarzaNL 64450Mexico

The production of thermostable laccases from a native strain of the white-rot fungus Pycnoporus sanguineus isolated in Mexico was enhanced by testing different media and a combination of inducers including copper sulfate（CuSO4）.The best conditions obtained from screening experiments in shaken flasks using tomato juice,CuSO4,and soybean oil were integrated in an experimental *** levels of tomato juice as the medium,CuSO4and soybean oil as inducers（36.8%（v/v）,3 mmol/L,and 1%（v/v）,respectively） were determined for 10 L stirred tank bioreactor *** combination resulted in laccase titer of 143000 IU/L（2,2＇-azino-bis（3-ethylbenzthiazoline-6- sulfonic acid）,pH 3.0）,which represents the highest activity so far reported for *** in a 10-L *** interesting media resulting from the screening included glucose-bactopeptone which increased laccase activity up to 20000 IU/L,whereas the inducers Acid Blue 62 and Reactive Blue 19 enhanced enzyme production in this medium 10 *** on a partial characterization,the laccases of this strain are especially promising in terms of thermostability（half-life of 6.1 h at 60 °C） and activity titers.

关键词： Enhanced laccase production central composite design Screening media Inducers Tomato juice medium Soybean oil Copper sulfate

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Photocatalytic degradation of carbofuran in TiO_2 aqueous solution: Kinetics using design of experiments and mechanism by HPLC/MS/MS

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Journal of Environmental Sciences 2013年第8期25卷 1680-1686页

作者： Hai Yang Shuolin Zhou Huajie Liu Weiwei Yan Liping Yang Bing Yi College of Chemistry and Chemical Engineering Hunan Institute of Engineering College of Chemistry and Chemical Engineering Hunan Normal University South China Institute of Environmental Sciences Ministry of Environmental Protection

The photocatalytic degradation kinetics of carbofuran was optimized by central composite design based on response surface methodology for the first time. Three variables, TiO2 concentration, initial pH value and the concentration of carbofuran, were selected to determine the dependence of degradation efficiencies on independent variables. Response surface methodology modeling results indicated that the degradation efficiency of carbofuran was highly affected by the initial pH value and the concentration of carbofuran. Then nine degradation intermediates were detected by HPLC/MS/MS. The Frontier Electron Densities of carbofuran were calculated to predict the active sites on carbofuran attacked by hydroxyl radicals and photoholes. Point charges were used to elucidate the chemisorption pattern on TiO2 catalysts during the photocatalytic process. By combining the experimental results and calculation data, the photocatalytic degradation pathways of carbofuran were proposed, including the addition of hydroxyl radicals and the cleavage of the carbamate side chain.

关键词： carbofuran photocatalytic degradation central composite design kinetics mechanism

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Modeling and optimization of the parameters affecting the in-situ microencapsulation process for producing epoxy-based self-healing anti-corrosion coatings

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Particuology 2018年第1期16卷 59-69页

作者： Ali Ebrahiminiya Mohammad Khorram Shadi Hassanajili Mehdi Javidi School of Chemical and Petroleum Engineering Shiraz University Shiraz lran Department of Materials Science and Engineering School of Engineering Shiraz University Shiraz lran

Micro/nanocapsules of urea-formaldehyde resin loaded with linseed oil, which are a self-healing agent in glass flake epoxy anti-corrosion paint, were prepared using a combination of ultrasonic homogenization and in-situ polymerization. The main objective of this study was to model and optimize the microen- capsulation process. Five-level central composite design was used to design, model, and optimize the microencapsulation process. A quadratic model was constructed to show the dependency of the per- centage of encapsulated linseed oil and capsule size, as model responses, on the studied independent variables （the rotational speed of the agitator and the power and duration of sonication）. Analysis of vari- ance showed that all of the variables have significant effects on the encapsulated linseed oil percentage, while the rotational speed of the agitator and sonication time is effective variables for controlling the capsule size. Under the determined optimum conditions, a maximum encapsulated linseed oil percentage （ELO%） of 93.9% and a minimum micro/nanocapsule size of 0.574 μm were achieved at 594 rpm agitation, 350 W sonication power, and 3 min sonication time. Validation of the model was performed. The percent- age relative errors between the predicted and experimental values of the ELO% and micro/nanocapsule size are 1.28% and 3.66%, respectively. The efficacy of the optimum micro/nanocapsules in healing cracks in a glass flake epoxy paint and corrosion protection was investigated by the salt spray test and Tafel polarization technique.

关键词： Urea-formaldehyde Response surface methodology central composite design Ultrasonic homogenization Linseed oil Self-healing coating

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Response surface methodology analysis of the photocatalytic removal of Methylene Blue using bismuth vanadate prepared via polyol route

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Journal of Environmental Sciences 2012年第9期24卷 1694-1701页

作者： Abdul Halim Abdullah Hui Jia Melanie Moey Nor Azah Yusof Advanced Materials and Nanotechnology Laboratory Institute of Advanced TechnologyUniversiti Putra MalaysiaUPM SerdangSelangor 43400Malaysia Department of Chemistry Faculty of ScienceUniversiti Putra MalaysiaUPM SerdangSelangor 43400Malaysia

Visible-light driven photocatalyst bismuth vanadate （BiVO4） photocatalyst was synthesized by the polyol route using ethylene glycol. The precipitate was washed, dried and calcined at 450℃ for 3 hr. The sample was characterized by X-ray diffractometry （XRD）, field emission scanning electron microscopy （FE-SEM）, zeta potential, surface area （BET method） and band gap energy via diffuse reflectance spectroscopy （DRS）. The synthesized BiVO4 has a monoclinic phase with a surface area of 4.3 m2/g and a band gap energy of 2.46 eV. A majority of the particles were in the range of 90-130 nm as obtained from the particle size distribution histrogram. The efficiency of the sample as a visible-light driven photocatalyst was examined by photodegrading Methylene Blue （MB）. The effects of some operational photodegradation parameters such as mass loading, initial dye concentration and pH were also examined. Experimental design methodology was applied by response surface modeling and optimization of the removal of MB. The multivariate experimental design was employed to develop a quadratic model as a functional relationship between the percentage removal of MB and three experimental factors （BiVO4 loading, MB initial concentration and pH）. The percentage removal of MB approached 67.21% under optimized conditions. In addition, a satisfactory goodness-of-fit was achieved between the predictive and the experimental results.

关键词： ethylene glycol photocatalysis zeta potential optimization central composite design

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Optimization of low-temperature alkaline smelting process of crushed metal enrichment originated from waste printed circuit boards

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Journal of central South University 2015年第5期22卷 1643-1650页

作者：郭学益刘静欣 School of Metallurgy and Environment Central South University

A novel low-temperature alkaline smelting process is proposed to convert and separate amphoteric metals in crushed metal enrichment originated from waste printed circuit boards. The central composite design was used to optimize the operating parameters,in which mass ratio of Na OH-to-CME, smelting temperature and smelting time were chosen as the variables, and the conversions of amphoteric metals tin, lead, aluminum and zinc were response parameters. Second-order polynomial models of high significance and3 D response surface plots were constructed to show the relationship between the responses and the variables. Optimum area of80%-85% Pb conversion and over 95% Sn conversion was obtained by the overlaid contours at mass ratio of Na OH-to-CME of4.5-5.0, smelting temperature of 653-723 K, smelting time of 90-120 min. The models were validated experimentally in the optimum area, and the results demonstrate that these models are reliable and accurate in predicting the smelting process.

关键词： low-temperature alkaline smelting waste printed circuit board amphoteric metals central composite design conversion

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