响应面法优化微电解工艺处理PNP废水

试验采用微电解工艺处理模拟对硝基酚(PNP)废水。以铁碳为微电解填料,采用响应面法中Box-Behnken试验设计模型,以铁屑投加量、溶液初始pH值、反应时间等因素为考察指标,研究各因素及其交互作用对PNP废水去除率的影响。结果表明:PNP废水质量浓度为200mg/L、铁屑投加量为50g/L、pH值为2.5、反应时间为120min时,PNP和COD去除率分别达到96.05%和48.69%,与预测值仅相差0.29%和0.18%。可见,响应面法用于优化铁碳微电解工艺处理对硝基酚废水是可行且合适的。     

单层球面网壳中响应面法的交叉项研究

不考虑交叉项的二次超曲面的响应面方法常用于工程结构的可靠性分析中,但在数学上无法证明该响应面构筑是否真实.本文通过对单层球面网壳在竖向简谐荷载下可靠指标的分析,发现了给定失效指标和结构位移响应之间的关系,获得了是否需要考虑交叉项进行可靠性分析的量化指标.     

电气石超细粉吸附水体中Cu、Pb、Zn和Cd

研究了电气石对水中重金属离子Cu(Ⅱ)、Pb(Ⅱ)、Zn(Ⅱ)和Cd(Ⅱ)的吸附性能.电气石能有效去除水中重金属离子,其选择性吸附顺序是Pb(Ⅱ)＞Cu(Ⅱ)＞Cd(Ⅱ)＞Zn(Ⅱ).电气石对重金属离子的吸附量随着溶液中重金属浓度的增加而增加,60 min能达到吸附平衡.电气石能够提高金属溶液的pH值.电气石对Cu(Ⅱ)、Pb(Ⅱ)、Zn(Ⅱ)和Cd(Ⅱ)的饱和吸附量分别是78.86、154.08、67.25和66.67 mg/g.温度为25～55℃时对电气石吸附重金属的影响较小.四种重金属离子的吸附均符合Langmuir吸附等温线.电气石对混合溶液中的Cu(Ⅱ)、Pb(Ⅱ)、Zn(Ⅱ)和Cd(Ⅱ)具有竞争性吸附.试验结果表明,电气石可以作为一种有效的吸附剂去除水中的重金属.     

脉冲电絮凝处理电镀废水的工艺优化与应用

以实际电镀厂废水为研究对象,采用铁电极板电絮凝技术,考察比电流、溶液初始pH值、占空比和曝气强度等参数对废水中镍和铬去除效果的影响,并利用响应面法优化了电絮凝工艺。结果表明,当比电流为122 A/m³、占空比为48%、初始p H值为7. 1、曝气强度为2. 4 L/L时,电解30 min后,对Ni²⁺、Cr⁶⁺和总铬的去除率分别为99. 65%、100%、100%,比能耗为0. 757kW·h/m³,与传统的单因素试验相比,降低了11. 87%。实际工程废水的处理规模为30 m³/h,400多天的运行效果表明,经响应面优化的电絮凝工艺运行稳定,出水水质达标。     

基于响应面法的单层球壳简谐荷载下的破坏形式判别

为了减小单层球面网壳在简谐荷载作用下的破坏形式判别中的计算量,避免反复试算,节约后处理时间,提出了利用响应面法计算结构可靠指标从而判别失效类型的方法:利用响应面法计算单层球面网壳在简谐荷载下基于位移失效模式的可靠指标;建立可靠指标和破坏形式之间的明确对应关系;获得判别单层球面网壳破坏形式的量化指标。研究表明,该方法能够准确地判别出结果,并具有高效率和实用性。     

响应面法优化黑曲霉产葡萄糖氧化酶的发酵条件

运用响应面法对黑曲霉(Aspergillus niger)产葡萄糖氧化酶发酵条件进行了优化。根据单因素试验结果,利用Plackett-Burman进行两因素两水平设计对影响其产酶因素进行评估并筛选出具显著效应的3种因素:葡萄糖、MgSO4·7H2O和转速。用最陡爬坡试验逼近以上三种因素的最大响应面区域后,采用Box-Behnken进行三因素三水平的设计以及响应面分析,获得最佳产葡萄糖氧化酶的培养基和培养条件组成。结果表明,发酵黑曲霉的最佳产酶条件为:葡萄糖241g/L,NaNO33g/L,K2HPO41g/L,FeSO40.01g/L,KCl 0.5 g/L,MgSO4·7H2O 0.36g/L,转速168 r/min,温度30℃。在此条件下进行产酶重复试验5次,酶活力为227.93U/g,比优化前提高了95.9%。     

基于序列响应面法的预应力单双层网壳可靠性研究

预应力单双层网壳是一种新型结构体系,具有较好的室内视觉效果和良好的经济性,在对本结构已有研究基础上,本文对其可靠性进行了研究,指出了应考虑钢索的松弛失效与多种荷载工况。针对有限元分析软件现有的可靠度程序计算量大的不足,提出了一种联合应用有限元软件与数学软件的改进方法,并编制了计算程序SEPR,在保证计算精度的同时,使计算效率明显提高。     

基于响应面法的赤泥烧结砖烧结工艺参数优化

以赤泥、淤泥和高岭土为主要原料制备烧结砖,研究烧结温度、保温时间、坯料粒度3个工艺参数对赤泥烧结砖吸水率的影响。利用响应面法(RSM)建立了3个工艺参数与吸水率之间的数学模型并对统计数据进行了方差分析。结果表明,最佳烧结工艺参数为:烧结温度1180℃、保温时间32 min、颗粒度125μm,样品吸水率为14.9%,与预测值相差4%,测试结果与数学模型拟合度较高,该模型能够较好的预测赤泥烧结砖的吸水率。     

大跨度斜拉桥基于二次响应面法的动力可靠度分析

结合三种方法,构造了一种二次响应面法,通过拟合的多项式函数来近似替代表示结构随机输入与输出变量之间作用关系的功能函数,按照结构的破坏准则及其极限状态方程,计算结构随机问题可靠度的组合响应面法。通过对大跨度苏通桥斜拉桥结构可靠性分析的研究得出,苏通大桥考虑承台固结在随机地震荷载作用下,结构有足够的安全度。同时,不同墩位的可靠度指标是不同的。通过分析发现苏通大桥各截面可靠指标相差不大,说明设计非常合理,两种计算动力可靠指标的方法不尽相同但计算结果比较接近,最大差值为5％左右。     

基于拓扑和响应面法的破拆机器人臂优化分析

臂架是实现破拆作业的最主要部件,其质量约占整车总质量的三分之二,因此在保证足够的强度条件下,进行优化设计就显得格外重要.本文以臂架系统的第一节臂为例,进行了优化过程说明,首先对臂架原始模型进行静力学仿真分析,之后利用拓扑优化方法对应力较大处的第一节臂进行结构优化,并对拓扑优化后的模型校核验证其可行性.最后通过响应面法对破拆机第一节臂典型尺寸进行灵敏度分析与尺寸优化.     

Adsorption of Pb and Cd by amine-modified zeolite

Natural zeolites, known for their excellent sorption properties towards metal cations, are widely used for the purification of wastewaters. The selectivity of clinoptilolite, a common zeolite mineral, for Pb is known to be particularly high, whereas its selectivity for Cd is often lower. Extraordinarily high sorption capacities for soft metal cations were observed in the case of thiol-functionalized silica gels and clays. In order to enhance the zeolites' sorption capacity for Cd, we treated natural heteroionic and Na-clinoptilolite in aqueous suspensions with cysteamine and propylamine solutions and investigated the sorption of Cd and Pb to amine-modified zeolite by a series of batch experiments. Stability constants for amine sorption on all zeolite samples at room temperature and 50 degrees C were obtained. Partial dimerization of cysteamine explains the enhanced sorption of this compound. In contrast, amine treatment did not enhance the adsorption capacity or selectivity of the clinoptilolite towards Cd and Pb. Instead, the amounts of adsorbed heavy metals decreased stoichometrically with increasing sorption of cysteamine and propylamine. This reduction can be explained by the blockage of channels by amine molecules and revealed that the modification of zeolites with mercaptoamines does not enhance the sorption capacity of zeolite for Cd and Pb.     

原子吸收光谱法测定活性污泥中Cu、Zn、Pb、Cd、Ni

采用微波消解技术消解城市污水处理厂污泥样品,用火焰原子吸收光谱法测定Cu、Zn,石墨炉原子吸收光谱法测定Pb、Cd、Ni。通过测定国家标准参考物质和加标回收试验,对方法进行了验证,方法的精密度和准确度均能满足污泥环境样品的测试要求。在试验条件下,测定样品中Cu、Zn、Pb、Cd、Ni的加标回收率在95.2%～103%之间,相对标准偏差<3%。     

微波消解-原子吸收光谱法测定酵母中铁、铜、锰、铅、镉

采用微波消解-原子吸收光谱法测定了高活性干酵母中铁、铜、锰、铅及镉5种微量元素含量。用微波消解法处理样品,具有简便、快速的优点。方法的标准曲线线性关系良好(r=0.995~0.999),方法加标回收率在96.0%~103.0%,相对标准偏差(RSD,n=6)在2.0%~4.9%。表明方法具有较好的准确性和重复性,用于实际酵母样品的测定,获得了满意的结果。     

响应曲面法优化Anammox-MBR工艺及膜表征

针对膜生物反应器(MBR)的厌氧氨氧化(Anammox)工艺常面临反应参数难以调控、污泥菌种难以富集等问题,基于Box-Behnken响应曲面法对Anammox-MBR影响因素进行了研究,并模拟得到总氮去除率的二次回归方程。结果表明:在最佳总氮去除条件(温度为36℃、HRT为10.01 h、无机碳源浓度为0.90 mg/L)下,响应曲面优化后的实测总氮去除率(88.98%)与响应曲面拟合所得模型的预测值(89.29%)基本吻合,该模型可用于优化Anammox-MBR对总氮的去除效能。经响应曲面优化后,PVDF中空纤维膜的热力学稳定性下降,活化能降低;膜丝表面官能团发生了变化,增加了醛羰基、羧酸羰基、酯羰基和酮羰基等基团;中空纤维膜表面在调控优化过程中附着污泥、微生物等物质而导致粗糙度增加,总体上有向膜污染发展的趋势。     

Sources of Cd,Cu, Pb and Zn in biowaste

Biowaste, the separately collected organic fraction of municipal solid waste, can be reused for soil conditioning after composting. In this way, environmentally harmful waste management strategies, such as landfilling or incineration, can be reduced. However, frequent application of composts to soil systems may lead to the accumulation of heavy metals in soils, and therefore legal criteria were laid down in a decree to guarantee the safe use of composts. The heavy metal content of biowaste-composts frequently exceeds the legal standards, and thus raises a conflict between two governmental policies: the recycling of solid waste on the one hand, and the protection of natural ecosystems and public health on the other hand. In this study, the heavy metal content (Cd, Cu, Pb and Zn) of biowaste was compared with the natural background content of Cd, Cu, Pb and Zn in the different constituents of biowaste. For this, the physical entities of biowaste were physically fractionated by wet-sieving and subsequent water-elutriation. In this way, organic and inorganic fractions of different particle sizes were obtained and the content of Cd, Cu, Pb and Zn and the organic matter content of the different fractions were determined. On the basis of particle size, density and visual appearance, the particle-size fractions were assigned to various indoor and outdoor origins of the biowaste. It was found that a large amount of biowaste was not organic, but over 50% was made up of soil minerals due to the collection of biowaste constituents from gardens. The heavy metal content of the various fractions in biowaste was compared with the natural background contents of heavy metals in the constituents of biowaste, i.e. food products, plant material, soil organic matter and soil minerals, by collecting literature data. The heavy metal content in the fractionated physical entities of biowaste corresponded with the natural background concentration of its constituents and indicated that biowaste was not contaminated by other sources. However, the natural background content of biowaste constituents will result in heavy metal contents for biowaste-compost that will exceed the legal standards. It is advised that the legal standards for composts should be critically re-examined. The protection of soil systems could be better guaranteed if the input of heavy metals was evaluated for all inputs of fertilisers and soil conditioners, i.e. animal manures, various types of compost and artificial fertilisers.     

X-射线荧光光谱法测定锌铝铜合金中的铝、铜、铁、硅、镍、铅和镉

建立了X射线荧光光谱法测定锌铝铜合金ZnAl6Cu1中铝、铜、铁、硅、镍、铅和镉的分析方法。探讨了各元素的分析条件,比较了不同制样方式及不同放置时间对铝强度的影响。在最佳的仪器分析条件下,测定了微量元素的检出限及主、次元素的精密度和准确度。检出限结果表明:各微量元素的检出限均满足标准要求,Cd和Pb元素的定量限稍高。精密度和准确度结果表明,铝、铜、铁元素的测量相对标准偏差在2.1%~5.9%,分析结果与国家标准方法一致。     

Influence of surfactants on the determination of Cu, Pb and Cd by ASV

In anodic stripping voltammetric studies using a thin film Hg electrode and an acetate buffered base solution containing NaCl, peak currents were found to be influenced by the presence of surfactants of different charge types. The addition of mg l⁻¹ amounts of di-stearyl dimethyl ammonium chloride, lauryl dimethyl-benzyl ammonium chloride, sodium alkyl-benzene sulfonate, sodium salt of sulfonated lauryl alcohol polyoxyethylene condensate, coconut mono-ethanol-amide ethoxylate or octa-decylamine ethoxylate caused enhancement of Cu (20%) and Pb (10%) peaks and suppression of Cd response. The magnitude of the induced changes was not directly related to surfactant type, or experimental parameters, and as a result it is recommended that when analysing waters suspected of containing surfactants, extra care should be taken in the calibration stage.     

响应面法优化棘孢木霉产厚垣孢子发酵工艺

采用响应面法(Box-Benhnken Design)对影响棘孢木霉(Trichoderma asperellum)ZJSX5003菌株产厚垣孢子的4个主要因素(黄豆饼粉-玉米粉用量,甘油添加量,装液量,初始pH)进行了研究。通过对试验数据进行方差分析考察了各因素及其交互作用对厚垣孢子产量的影响;进行回归分析并建立基于统计学的回归方程,计算获得最佳发酵条件:大豆饼粉-玉米粉用量33.25g/L、甘油添加量8.86ml/L、装液量99.35ml/500ml、初始pH值3.26,此时预测的厚垣孢子产量为9.56×10⁷个/ml。在此条件下,实际测得厚垣孢子产量为9.84×107个/ml。在此条件下,实际测得厚垣孢子产量为9.84×10⁷个/ml,达到理论预测值的97.07%,且比优化前提高了69.07%,进一步采用10L发酵罐进行适用性验证,厚垣孢子产量达到1.75×107个/ml,达到理论预测值的97.07%,且比优化前提高了69.07%,进一步采用10L发酵罐进行适用性验证,厚垣孢子产量达到1.75×10⁸个/ml,比摇瓶发酵的产量高,为木霉菌厚垣孢子菌剂开发提供了理论依据。     

Box-Behnken效应面法优化玄参的提取工艺

目的:应用Box-Behnken效应面法优化玄参的提取工艺。方法:以乙醇体积分数、溶媒比、提取时间为自变量,以总评"归一值"(包括安格洛苷C、哈巴苷、哈巴俄苷的含量及浸膏率)作为因变量,对自变量的各个水平采用二项式拟合,用Box-Behnken效应面法对提取工艺进行优化。结果:玄参的最优提取工艺为:提取时间75min,溶媒比为8倍,82%的乙醇,提取2次。二项式拟合复相关系数高(r=0.9777),回归模型的预测值与测定值的偏差率为-2.51%。结论:Box-Behnken效应面法优选的玄参提取工艺,合理可行,操作简便。     

微波消解AAS、AFS法测定不同产地红花中As、Hg、Pb、Cd、Cu含量

目的:测定云南4个产地红花的重金属含量,了解4份红花样品中重金属元素的蓄积情况。方法:采用微波消解法进行样品前处理,双道原子荧光光度法测定砷(As)、汞(Hg)的含量,石墨炉原子吸收光谱法测定镉(Cd)、铅(Pb)的含量,空气-乙炔火焰原子吸收光谱法测定铜(Cu)的含量。结果:不同产地红花的重金属含量有一定的差异,但各产地红花药材中砷(As)、汞(Hg)、镉(Cd)、铅(Pb)、铜(Cu)的含量均符合限量标准。结论:本研究所建立的重金属检测方法,既可用于质量控制,也可为不同种类中药材中重金属含量测定提供参考。