用甲基异丁基甲酮从电子废料中萃取金及条件优化

以电子废料中的金为研究对象,用统计学方法对甲基异丁基甲酮(MIBK)萃取电子废料中金的影响因素进行了探讨和分析.同时,通过Plackett-Burman实验设计筛选出相比、萃取时间和萃取温度为主要影响因素,并应用响应面方法分析得到了这3个因素的优化结果.数据统计分析结果表明,最佳的萃取条件为相比0.58、萃取时间9.0min、萃取温度20℃,在此条件下金的萃取率最高可达98.36%.萃取液经质量分数5%的草酸溶液还原,反萃金的回收率可达到96.2%.     

响应面法优化海洋细菌MP-2酯酶发酵条件

采用响应面法(Response surfsce methodology)对海洋细菌MP-2酯酶的发酵条件进行了优化.首先采用了Placken-Burman方法对影响酯酶发酵的因素进行评价,筛选出了3个显著因素为豆饼粉、花生粕和种龄,并利用DesignExpert 7.0.3软件完成RSM法对显著性因素的进一步优化从而确定最佳条件.当花生粕0.9%;豆饼粉2.29%;接种量5·98%时,此时预测的最大酯酶活力为334.46 U/mL.在最佳发酵条件下,优化后该酯酶活力由258.8 U/mL提高到318.2 U/mL.实际酶活力达到理论预测值的95%,十分接近.     

Isolation and identification of a bioflocculant-producing strain and optimisation of cultural conditions via a response surface model

A bioflocculant-producing strain named MY6-2 was isolated from a mixed activated sludge by a nitrogen-free medium. Based on 16S rDNA sequence, biochemical and morphological characteristics, the strain MY6-2 was identified as Bacillus mucilaginosus. The chemical analysis indicated that the flocculant MY6-2 was mainly composed of extracellular polysaccharide. The result of the composition of the medium showed that MY6-2 was able to generate bioflocculant in a nutrient-poor medium that consisted of 5?g?L^?1 sucrose and no nitrogen source. Response surface methodology (RSM) was used to optimise the fermentation condition of MY6-2 for maximum flocculating activity by using central composite design (CCD). Based on the result, the optimum conditions were as follows: 100?mL of broth in a 250?mL Erlenmeyer flask, initial pH 8.0 and inoculum concentration 10%, respectively. The highest flocculating rate of 90% was achieved under these conditions by adding 0.5?mL fermentation supernatant to 95?mL of Kaolin suspension.     

Co-pyrolysis of paper waste and mustard press cake in a semi-batch pyrolyzer—optimization and bio-oil characterization

Under the present research study, the co-pyrolysis of paper waste and mustard press cake was conducted in a 50 mm diameter and 640 mm long semi-batch pyrolyzer in the temperature range of 673 to 1173 K in nitrogen atmosphere and synergistic relationship between the pyrolysis of two feed stocks has been observed. The paper wastes were composed of local packing paper, newspaper-based food packets of grocery, and printing paper in the ratio of 6:3:1. During co-pyrolysis, response surface methodology (RSM) technique has been employed using Design Expert Version 7.0.0 to determine the collective effects of factors, namely, A: ratio of paper waste to mustard press cake and B: pyrolysis temperature, on the yield of bio-oil, energy yield, and oxygen content of bio-oil. Optimization has been done by using RSM to identify the individual sets of values of independent parameters corresponding to maximum bio-oil yield (A: 9.0:1, B: 874.75 K), energy yield (A: 8.80:1, B: 812 K), and minimum oxygen content of bio-oil (A: 2.75:1, B: 883.06 K). Bio-oil obtained at maximum energy yield condition has been characterized using the Gas chromatography–mass spectrometry (GC-MS) and Fourier transform infrared spectroscopy (FTIR) spectroscopic analyses. The array of compounds present in the bio-oil compounds has been compared with literature data available on pyro-oil obtained from similar feed stocks.     

铜绿微囊藻生长条件优化模拟研究

采用Plackett Burman实验设计与响应曲面法(RSM)相结合,研究了环境因子对铜绿微囊藻生长的影响。首先采用Plackett-Burman设计对影响藻细胞生长的环境因子进行筛选,结果表明:温度、NaNO3、K2HPO4、Ferric.Citrate对铜绿微囊藻的生长有重要影响,各因子影响值大小为E温度EK2HPO4ENaNO3EFerric.Citrate。在此基础上,用Box-Behnken设计对铜绿微囊藻的生长条件进一步优化,通过对藻细胞最大现存量与各考察因子之间的输入响应关系进行分析,结果表明:铜绿微囊藻的最佳生长条件是:温度为29℃,NaNO3为1.059 mmol/L,K2HPO4为0.057 mmol/L,Ferric.Citrate为0.024mmol/L,此时藻细胞的最大现存量为10.8293×105cells/mL。     

响应面法优化Fenton预处理干法腈纶废水

采用Fenton法预处理难降解干法腈纶废水,选取H2O2用量、Fe2+用量、初始pH和反应温度4个因素为变量,COD去除率为响应值进行中心组合设计。利用响应面法对实验结果进行分析,建立了以COD去除率为响应值的二次多项式模型并进行了显著性检验,分析了各因素单独及交互作用对COD去除率的影响,确定了最佳反应条件,并考察了最佳条件下处理前后废水可生化性和毒性变化。结果表明,所选取的4个因素影响COD去除率的主次顺序依次为:H2O2用量、Fe2+用量、初始pH和反应温度;在H2O2浓度为90.0 mmol/L、Fe2+浓度为23.9 mmol/L、初始pH值为3.4、温度为38.5℃的最佳条件下,COD去除率为53.8%,与模型预测值51.9%吻合度较高,偏差仅为3.66%;最佳条件下处理后废水可生化性显著提高,生物毒性明显降低,适宜于后续的生化处理。     

响应面法优化UV／H2O2光氧化法处理高浓度LAS废水

采用响应面法对UV／H2O2光氧化法处理高浓度LAS废水的工艺参数进行了系统研究。根据Box—BehnkenDesign（BBD）设计原理,以初始pH与H2O2投加量、反应时间和温度为主要影响因素,设计4因素3水平共29个实验点的实验方案,并建立了二次响应面拟合模型。方差分析表明,初始pH与H2O2投加量、反应时间和温度以及初始pH和H2O2投加量、H2O2投加量和温度之间的交互作用,对实验结果具有显著性影响。实验得到的光氧化高浓度LAS废水最佳工艺条件,pH为4．0,H2O2投加量为40mmol／L,反应时间为90min,温度为25℃,在此条件下,LAS的平均去除率为98．1％。     

响应面法优化聚磷硫酸铁的制备及其应用

采用单因素实验方法,针对制备聚磷硫酸铁(PPFS)的主要影响因素加以分析,包括酸度(nH2SO4/nFe2+、碱化度和nPO34-/nFe2+等。以生活污水中总磷(TP)的去除率为考察对象,采用Box-Behnken中心组合实验和响应面分析方法对主要影响因素加以优化,得到了二次响应曲面模型以及优化的水平值。结果表明,当把PPFS用于生活污水中TP的去除时,其最佳制备参数如下所列:酸度为0.1017,碱化度为12.21%,nPO34-/nFe2+为0.0560。通过回归分析,模型拟合性良好,在优化制备条件下得到的TP去除率预测值与实验值接近,误差为1.26%。     

响应面方法优化Fenton试剂处理甲萘酚废水

利用响应面方法(RSM)对Fenton试剂处理甲萘酚废水工艺过程进行优化,考察了Fe2+浓度、H2O2浓度和初始p H 3种工艺条件对甲萘酚废水处理效果的影响,并提出Fenton试剂降解甲萘酚废水的数学模型及优化后的工艺参数。Fenton试剂降解甲萘酚废水的数学模型可以较好地模拟真实的曲面,方程的F值为24.90,相关系数(R2)为0.9573,调整相关系数(R2adj)为0.9188。通过优化得到最佳的工艺参数Fe2+浓度为0.89 g/L,H2O2浓度为0.79 g/L,p H为4.00。在此条件下,COD去除率的预测值为91.15%,与实测值90.78%接近。说明建立的模型能真实地反映各主要因素的影响,模型与实际情况吻合。