The Influence of Tartaric Acid in the Silver Nanoparticle Synthesis Using Response Surface Methodology

Silver nanoparticles(AgNPs)synthesized using tartaric acid as a capping agent have a great impact on the reaction kinetics and contribute significantly to the stability of AgNPs.The protective layer formed by tartaric acid is an important factor that protects the silver surface and reduces potential cytotoxicity problems.These attributes are critical for assessing the compatibility of AgNPs with biological systems and making them suitable for drug delivery applications.The aim of this research is to conduct a comprehensive study of the effect of tartaric acid concentration,sonication time and temperature on the formation of silver nanoparticles.Using Response Surface Methodology(RSM)with Face-Centered Central Composite Design(FCCD),the optimization process identifies the most favorable synthesis conditions.UV-Vis spectrum regression analysis shows that AgNPs stabilized with tartaric acid are more stable than AgNPs without tartaric acid.This highlights the increased stability that tartaric acid provides in AgNP ssssynthesis.Particle size distribution analysis showed a multimodal distribution for AgNPs with tartaric acid and showed the smallest size peak with an average size of 20.53 nm.The second peak with increasing intensity shows a dominant average size of 108.8 nm accompanied by one standard deviation of 4.225 nm and a zeta potential of−11.08 mV.In contrast,AgNPs synthesized with polyvinylpyrrolidone(PVP)showed a unimodal particle distribution with an average particle size of 81.62 nm and a zeta potential of−2.96 mV.The more negative zeta potential of AgNP-tartaric acid indicates its increased stability.Evaluation of antibacterial activity showed that AgNPs stabilized with tartaric acid showed better performance against E.coli and B.subtilis bacteria compared with AgNPs-PVP.In summary,this study highlights the potential of tartaric acid in AgNP synthesis and suggests an avenue for the development of stable AgNPs with versatile applications.

Application of response surface methodology in medium optimization for pyruvic acid production of Torulopsis glabrata TP19 in batch fermentation

Response surface methodology (RSM) was used to optimize the fermentation medium for enhancing pyruvic acid production by Torulopsis glabrata TP19. In the first step of optimization, with Plackett-Burman design, ammonium sulfate, glucose and nicotinic acid were found to be the important factors affecting pyruvic acid production significantly. In the second step, a 23 full factorial central composite design and RSM were applied to determine the optimal concentration of each significant variable. A second-order polynomial was determined by the multiple regression analysis of the experimental data. The optimum values for the critical components were obtained as follows: ammonium sulfate 0.7498 (10.75 g/L), glucose 0.9383 (109.38 g/L) and nicotinic acid 0.3633 (7.86 mg/L) with a predicted value of maximum pyruvic acid production of 42.2 g/L. Under the optimal conditions, the practical pyruvic acid production was 42.4 g/L. The determination coefficient (R2) was 0.9483, which ensures adequate credibility of the model. By scaling up fermentation from flask to jar fermentor, we obtained promising results.

Optimization of the Extraction Technology of Chlorogenic Acid from Sunflower Meal Using Response Surface Methodology

[Objective]To optimize the ultrasonic-assisted extraction process of chlorogenic acid from sunflower meal.[Method]Based on the single-factor test,the extraction factors of ethanol concentration,extraction temperature and extraction time were optimized using the response surface methodology with the extraction rate of chlorogenic acid as the response value.[Result]The optimum extraction conditions of chlorogenic acid from sunflower meal were 57% of ethanol concentration,39 min of extraction time,53℃ of extraction temperature,100 W of ultrasonic power,1:14(g/ml)of solid-liquid ratio and one time of extraction.Under these conditions,the extraction rate of chlorogenic acid was 2.25%.[Conclusion]Ultrasonic assisted extraction method has high extraction rate but short time,the study provides a theoretical basis for the industrialized production of chlorogenic acid in sunflower meal.

Modeling and Optimization of Two Clays Acidic Activation for Phosphate Ions Removal in Aqueous Solution by Response Surface Methodology

This work deals with phosphate ions removal in aqueous solution by adsorption carried out using two clays, both in activated form. One, non-swelling clay, rich in kaolinite, is associated with illite and quartz. The other, swelling, richer in montmorillonite, is associated with kaolinite, illite and quartz. Seven factors including these two clays were taken into account in a series of experimental designs in order to model and optimize the acidic activation process favoring a better phosphate removal. In addition to the choice of clay nature, the study was also interested in the identification of the mineral acid, between hydrochloric acid and sulfuric acid, which would promote this acidic activation. Response Surface Methodology (RSM) was used for this purpose by sequentially applying Plackett and Burman Design and Full Factorial Design (FD) for screening. Then, a central composite design (CCD) was used for modeling the activation process. A mathematical surface model has been successfully established. Thus, the best acidic activation conditions were obtained by activating the montmorillonite clay with a 2N sulfuric acid solution, in an acid/clay mass ratio of 7.5 at 100°C for 16H. The phosphate removal maximum rate obtained was estimated at 89.32% ± 0.86%.

Extraction of seed oil from Diospyros lotus optimized using response surface methodology

Oil from seeds of Diospyros lotus was extracted using a conventional method with two different solvents:hexane and petroleum ether. A central composite design with response surface methodology were used to optimize the process. A second-order polynomial equation was employed, and ANOVA was applied to evaluate the impact of various operating parameters including extraction temperature(x_1; 44.9–70.1 °C), extraction time(x_2;5.0–10.0 h) and solvent to solid ratio(x_3;11.6–28.4 mL g^(-1)), on oil yield. Experiments to validate the model showed decent conformity between predicted and actual values. Extraction conditions for optimal oil yield were 61 °C, 8.75 h extraction duration and 19.25 mL g^(-1) solvent to solid ratio. Under these conditions, the oil yield was predicted to be 5.1340%. Oil samples obtained were then analyzed using gas chromatography. The fatty acid composition revealed the major fatty acids to be oleic acid(C18:1) and linoleic acid(C18:2). The analysis of oil also demonstrated a decent ratio between omega-3 and omega-6 fatty acids. The structure of seeds was imaged using scanning electron microscopy. Oil quality was analyzed thermogravimetrically and by Fourier transform infrared spectroscopy. The assigned nutritional features of the D. lotus oil suggested that it can be used as an edible oil in pharmaceutical and food industry in the future.

Production of octyl levulinate biolubricant over modified H-ZSM-5:Optimization by response surface methodology

The present study highlighted the use of modified H-ZSM-5 （Meso-HZ-5） as heterogeneous catalyst for the synthesis of octyl levulinate biolubricant by catalytic esterification of biomass derived renewable levulinic acid （LA） with n-octanol. The process variables such as catalyst loading （X1）, n-octanol to LA molar ratio （X2） and reaction temperature （X3） were optimized through response surface methodology （RSM）, using Box-Behnken model. Analysis of variance was performed to determine the adequacy and significance of the quadratic model. The yield of octyl levulinate was obtained to be 99% at optimum process parameters. The developed quadratic model was found to be adequate and statistically accurate with correlation value （R2） of 0.9971 to predict the yield of octyl levulinate biolubricant. The study was also extended on the validation of theoretical and experimental data, including catalyst reusability.

Application of response surface methodology(RSM) for optimization of leaching parameters for ash reduction from low-grade coal

Coal is the world's most abundant energy source because of its abundance and relatively low cost. Due to the scarcity in the supply of high-grade coal, it is necessary to use low-grade coal for fulfilling energy demands of modern civilization. However, due to its high ash and moisture content, low-grade coal exerts the substantial impact on their consumption like pyrolysis, liquefaction, gasification and combustion process. The present research aimed to develop the efficient technique for the production of clean coal by optimizing the operating parameters with the help of response surface methodology. The effect of three independent variables such as hydrofluoric acid(HF) concentration(10–20% by volume), temperature(60–100 °C), and time(90–180 min), for ash reduction from the low-grade coal was investigated. A quadratic model was proposed to correlate the independent variables for maximum ash reduction at the optimum process condition by using central composite design(CCD) method. The study reveals that HF concentration was the most effective parameter for ash reduction in comparison with time and temperature. It may be due to the higher F-statistics value for HF concentration, which effects to large extent of ash reduction. The characterization of coal was evaluated by Fourier transform infrared spectroscopy(FTIR) analysis and Field-emission scanning electron microscopy with energy-dispersive X-ray(FESEMEDX) analysis for confirmation of the ash reduction.

Analysis of Metabolic Products by Response Surface Methodology for Production of Human-like Collagen II

Recombinant Escherichia coli BL21 is used to produce human-like collagen. The key constituents of media are optimized using response surface methodology (RSM). Before thermal induction, the highest biomass production and the lowest production of some hazardous by-products, especially acetic acid, were obtained in the media containing 0.085 mol·L-1 glucose and 0.019 mol·L-1 nitrogen (carbon-nitrogen ratio, 4.47:1). After thermal induction, when the concentrations of glucose and nitrogen in the media were 0.065 mol·L-1 and 0.017 mol·L-1 , respectively (carbon-nitrogen ratio, 3.82:1), the productivity of human-like collagen per cell was the highest while that of acetic acid was the lowest. The extended analysis showed that the production of lactic acid and propionic acid increased while that of some intermediate acids of the tricarboxylic acid cycle decreased if the dose of glucose increased.

Extraction Optimization of Polysaccharides from Rhizoma Polygonati by Response Surface Methodology and Content Determination

[Objectives]This study aimed to investigate the water extraction-alcohol precipitation technology and content determination method of polysaccharides in Rhizoma Polygonati.[Methods]Taking the content of polysaccharides in the extract as the indicator,the extraction process was optimized using single-factor tests and Box-Behnken Design.The content of polysaccharides extracted was determined by the anthrone-sulfuric acid method.Among the three factors in the test design,the solid/liquid ratio and extraction time had a significant effect(P<0.05,P<0.01),while the extraction temperature had no effect on the content of polysaccharides extracted(P>0.05).[Results]The optimal extraction process for polysaccharides in Rhizoma Polygonati was as follows:liquid/solid ratio 20∶1(mL/g),extraction time 2 h,and extraction temperature 85℃.Under the optimal extraction process,the content of polysaccharides in the extract reached 12.50%.[Conclusions]The extraction process optimized by response surface methodology for polysaccharides in Rhizoma Polygonati is reliable and has practical value,and can be used to guide production practices.

Utilization of Virgin Coconut Meal (VCM) in the Production of Ready-to-Eat Indian Traditional Sweet Meat Using Response Surface Methodology

Virgin coconut meal (VCM) was used for the development of ready-to-eat Indian traditional sweet meat commonly known as “ladoo” both with and without sorbic acid (0.3%). The different ingredients were optimized following re-sponse surface methodology with three independent variables i.e. sugar, water and VCM and sensory attributes as responses. The changes in the quality of VCM ladoo packed in polypropylene (PP, 75 μ) and laminates of metalized polyester (MP, 75 μ) were monitored during storage to establish the shelf life under ambient temperature conditions (15?C - 34?C). Samples without added potassium sorbate spoiled within three weeks of storage due to mold growth and fermented odour. VCM ladoo containing sorbic acid did not support any microbial growth during storage up to 4 months, however, during storage samples packed in PP lost moisture and became hard and brittle, while those packed in MP remained soft. Peroxide and thiobarbituric acid values were higher in PP packed samples as compared to those packed in MP. Sorbic acid degraded during storage of ladoo and the rate of degradation was higher in PP packed ladoos than that in MP packed ones.

Wastewater-nitrogen removal using polylactic acid/starch as carbon source： Optimization of operating parameters using response surface methodology

Nitrogen removal from ammonium-containing wastewater was conducted using polylactic acid （PLA）/ starch blends as carbon source and carrier for fimctional bacteria. The exclusive and interactive influences of operating parameters （i.e., temperature, pH, stirring rate, and PLA-to-starch ratio （PLA proportion）） on nitrification （Y1）, denitrification （Y2）, and COD release rates （Y3） were investigated through response surface methodology. Experimental results indicated that nitrogen removal could be successfully achieved in the PLA/starch blends through simultaneous mtnncatlon anti clenltnncatlon. The carbon release rate of the blends was controllable. The sensitivity of Y1, Y2, and Y3 to different operating parameters also differed. The sequence for each response was as follows： for Y1, pH 〉 stirring rate 〉 PLA proportion 〉 temperature; for Y2, PH 〉 PLA proportion 〉.temperature.〉 stirring rate; and for Y3, stirring rate 〉pH 〉 PLA proportion 〉 temperature. In this study, the following optimum conditions were observed： temperature, 32.0℃; pH 7.7; stirring rate, 200.0 r · min^-1 and PLA proportion 0.4. Under these conditions Y1 Y2 and Y3 were 134.0 μg-N·g-blend^-1·h^-1, 160.9μg-N-g-blend^-1·h^-1, and 7.6 × 10^3 μg-O·g-blend^-1·h^-1, respectively. These results suggested that the PLA/starch blends may be an ideal packing material for nitrogen removal.

Optimization of succinic acid fermentation with Actinobacillus succinogenes by response surface methodology(RSM)

Succinic acid is considered as an important platform chemical.Succinic acid fermentation with Actinobacillus succinogenes strain BE-1 was optimized by central composite design(CCD)using a response surface methodology(RSM).The optimized production of succinic acid was predicted and the interactive effects between glucose,yeast extract,and magnesium carbonate were investigated.As a result,a model for predicting the concentration of succinic acid production was developed.The accuracy of the model was confirmed by the analysis of variance(ANOVA),and the validity was further proved by verification experiments showing that percentage errors between actual and predicted values varied from 3.02%to 6.38%.In addition,it was observed that the interactive effect between yeast extract and magnesium carbonate was statistically significant.In conclusion,RSM is an effective and useful method for optimizing the medium components and investigating the interactive effects,and can provide valuable information for succinic acid scale-up fermentation using A.succinogenes strain BE-1.

Optimization of lychee wine fermentation process using response surface methodology to reduce acetic acid content

Acetic acid is the main component of the volatile acid in the wine.However,excessive amounts of acetic acid negatively affect wine quality.The study aimed to decrease acetic acid content produced by Saccharomyces cerevisiae fermentation after adding metal ion at different temperatures.Response surface methodology(RSM)was used to predict the optimum conditions for acetic acid removal.A central composite design was employed for the experiments and results were analyzed to obtain the best possible combination of fermentation temperature(X1:16℃-24℃)and concentrations of potassium(X2:0-12.0 mM),magnesium(X3:0-8.0 mM),and calcium ions(X4:0-0.2 mM)that would generate the minimum acetic acid in lychee wine at an initial acetic acid concentration of 1.5 g/L.Experimental data were fitted to a second-order polynomial equation using multiple regression analysis and analyzed using analysis of variance(ANOVA).During fermentation under pre-established conditions,the correlation coefficients R2 and Adj-R2 of the models for acetic acid removal were 0.9487 and 0.9007,respectively.After testing,the optimum conditions for acetic acid removal were determined as follows:fermentation temperature of 20℃;potassium,magnesium,and calcium ion concentrations of 10.1 mM,6.1 mM,and 0.2 mM,respectively.The experimental acetic acid content of lychee wine under optimal conditions was found to be 0.309 g/L,which agreed well with the model-predicted value of 0.314 g/L.

Adsorption property of direct fast black onto acid-thermal modified sepiolite and optimization of adsorption conditions using Box-Behnken response surface methodology

The adsorption of direct fast black onto acid- thermal modified sepiolite was investigated. Batch adsorp- tion experiments were performed to evaluate the influences of experimental parameters such as initial dye concentra- tion, initial solution pH and adsorbent dosage on the adsorption process. The three-factor and three-level Box- Behnken response surface methodology （RSM） was utilized for modeling and optimization of the adsorption conditions for direct fast black onto the acid-thermal modified sepiolite. The raw sepiolite was converted to acid-thermal modified sepiolite, and changes in the fourier transform infrared spectrum （FTIR） adsorption bands of the sample were noted at 3435 cm] and 1427 cm1. The zeolitic water disappeared and the purity of sepiolite was improved by acid-thermal modification. The decoloriza- tion rate of direct fast black adsorbed increased from 68.2% to 98.9% on acid-thermal modified sepiolite as the initial solution pH decreased from 10 to 2. When the adsorbent dosage reached to 2.5 g. L-1, 2.0 g. L-~, 1.5 g. I,I and 1.0g.L-1, the decolorization rate was 90.3%, 86.7%, 61.0% and 29.8%, respectively. When initial dye concen- tration increased from 25 to 200 rag. L-l, the decolorization rate decreased from 91.9% to 60.0%. The RSM results showed that the interaction between adsorbent dosage and pH to be a significant factor. The optimum conditions were as follows： the adsorbent dosage 1.99 g.L-1, pH 4.22, and reaction time 5.2 h. Under these conditions, the decolor- ization rate was 95.1%. The three dimensional fluores- cence spectra of direct fast black before and after treatment showed that the direct fast black was almost all adsorbed by the acid-thermal modified sepiolite.

Response Surface Optimization of Nigella glandulifera Freyn Seed Oil Yield by Supercritical Carbon Dioxide Extraction

Supercritical carbon dioxide （SC-CO2） extraction was employed to extract oil from Nigella glandulifera Freyn seed in this study. Response surface methodology （RSM） was applied to evaluate the effects of the process parameters （pressure, temperature, and CO2 flow rate） on oil yield of N. glandulifera seed. A Box-Behnken design was used to optimize the extraction parameters. The analysis of variance indicated that the linear coefficients of pressure and CO2 flow rate, the quadratic term coefficients of pressure and temperature and the interactions between pressure and temperature, as well as temperature and CO2 flow rate, had significant effects on the oil yield （P〈0.05）. The optimal conditions to obtain the maximum oil yield from N. glandulifera seed were pressure 30.84 MPa, temperature 40.57°C, and CO2 flow rate 22.00 L h-1. Under these optimal conditions, the yield of oil was predicted to be 38.19%. The validation experiment results agreed with the predicted values. The fatty acid composition of N. glandulifera seed oil extracted using SC-CO2 was compared with that of oil obtained by Soxhlet method. The results showed that the fatty acid compositions of oil extracted by the two methods were similar. Identification of oil compounds with gas chromatography-mass spectrometry （GC-MS） showed that the contents of unsaturated fatty acids linoleic acid （48.30%）, oleic acid （22.28%） and saturated fatty acids palmitic acid （16.65%）, stearic acid （4.17%） were the most abundant fatty acids in seed oil from N. glandulifera.

Recovery of Li, Ni, Co and Mn from spent lithium-ion batteries assisted by organic acids: Process optimization and leaching mechanism

The proper recycling of spent lithium-ion batteries(LIBs)can promote the recovery and utilization of valuable resources,while also negative environmental effects resulting from the presence of toxic and hazardous substances.In this study,a new environmentally friendly hydro-metallurgical process was proposed for leaching lithium(Li),nickel(Ni),cobalt(Co),and manganese(Mn)from spent LIBs using sulfuric acid with citric acid as a reductant.The effects of the concentration of sulfuric acid,the leaching temperature,the leaching time,the solid-liquid ratio,and the reducing agent dosage on the leaching behavior of the above elements were investigated.Key parameters were optimized using response surface methodology(RSM)to maximize the recovery of metals from spent LIBs.The maxim-um recovery efficiencies of Li,Ni,Co,and Mn can reach 99.08%,98.76%,98.33%,and 97.63%.under the optimized conditions(the sulfuric acid concentration was 1.16 mol/L,the citric acid dosage was 15wt%,the solid-liquid ratio was 40 g/L,and the temperature was 83℃ for 120 min),respectively.It was found that in the collaborative leaching process of sulfuric acid and citric acid,the citric acid initially provided strong reducing CO_(2)^(-),and the transition metal ions in the high state underwent a reduction reaction to produce transition metal ions in the low state.Additionally,citric acid can also act as a proton donor and chelate with lower-priced transition metal ions,thus speeding up the dissolution process.

响应面法优化南瓜风味发酵乳酸菌饮料的研制

为了研制出一款风味独特兼具营养的南瓜风味发酵酸乳饮料,本研究以自制南瓜发酵酸乳为原料,通过单因素实验和响应面试验设计,以感官评分为评价指标,确定了南瓜风味发酵乳酸菌饮料的最佳配方为:水料和酸奶体积比为4,柠檬酸添加量0.12%,糖添加量为8%。以《食品安全国家标准食品酸度的测定》(GB5009.239—2016)以及《含乳饮料》(GB/T21732—2008)为标准,测定南瓜风味发酵乳酸菌饮料的酸度为45°T,乳蛋白含量为0.71g/100g,乳酸菌活菌数为2.8×10^(6)CFU/g。以上所述,均符合国家标准。该南瓜风味发酵乳酸菌饮料口感较好,味道醇厚,有较多的乳酸菌含量,具有较好的市场开发前景。

双水相协同超声法提取枇杷叶中绿原酸的工艺研究

试验采用响应面法优化双水相协同超声法提取枇杷叶中绿原酸的工艺,探讨提取液中乙醇体积分数、超声温度、超声时间、磷酸氢二钾用量和超声功率对绿原酸提取率的影响。结果显示,双水相协同超声法提取枇杷叶中绿原酸最佳提取工艺条件为乙醇体积分数61%、超声温度61℃、超声时间25 min、磷酸氢二钾用量4.6 g,此条件下绿原酸提取率1.53%,与预测值相接近。研究表明,双水相协同超声法提取枇杷叶中绿原酸的提取工艺稳定可行,可为枇杷叶的资源化开发与利用提供参考。

响应曲面法优化废旧三元锂电池黑粉酸浸工艺

使用盐酸直接浸出废旧三元锂电池黑粉中的锂、镍、钴、锰,采用基于Box-Behnken设计的响应曲面法,考察反应温度、酸浓度、时间对4种元素浸出率的影响。结果表明,直接酸浸法最佳工艺条件为:酸浓度6 mol/L,固液比250 g/L,反应温度60℃,反应时间7 h,2次浸出后,锂浸出率为99.96%,镍浸出率为99.73%,钴浸出率99.90%,锰含量为99.82%。