近临界水氧化处理模拟核废弃萃取溶剂及响应面优化

使用连续的超临界氧化设备,对模拟放射性废萃取剂在近临界水氧化条件下进行处理,采用响应面法对工艺参数进行优化,建立温度、压力、反应时间、过氧系数与COD去除率的二次回归模型,分析各因素显著性和交互作用。结果表明,温度和反应时间的交互作用对COD去除率影响最为显著,影响反应过程的因素由高到低为:反应温度、停留时间、反应压力和过氧系数。最佳工艺为温度506℃,压力21 MPa,停留时间158 s,过氧系数2.8。实验验证COD去除率达到99.75%⁹9.89%,与预测值99.91%无显著差异,此模型建立切实可行。模拟废液中加入硝酸锶以模拟放射性物质,在最优条件处理过程中,锶离子分离度达到99.92%,分离效果理想。     

亚临界萃取石榴籽油工艺的响应面优化

在单因素试验的基础上,运用响应面法优化石榴籽油的亚临界萃取工艺。结果表明萃取温度、萃取时间及液料比对石榴籽油得率有显著影响。优化得到的最佳工艺条件为:萃取温度38℃,萃取时间42min,液料比6。在此工艺条件下,石榴籽油得率达到21. 07%,与模型预测值21. 15%之间具有良好的拟合性。     

超(近)临界水氧化法降解炸药废水的工艺优化与动力学研究

炸药工业排放废水中含TNT、RDX、HMX等多种剧毒物质,一般难以生物降解甚至不可生物降解,处理非常困难.并且炸药废水的COD很大,对水体污染严重.文中采用超(近)临界水氧化技术,对TNT, RDX和HMX模拟炸药废水进行正交实验及反应动力学研究,在降解TNT, RDX和HMX同时降低废水的COD值.得到最佳氧化降解工艺条件为:反应温度648 K,反应时间5 min,模拟炸药废水:氧化剂(H_2O_2) (体积比)= 10:1,处理后废水的COD=38 mg·L~(-1),COD降解率为98.65%.动力学研究结果表明,在573 K、603 K、623 K、653 K时的表观速度常数k分别为:0.01030、0.02069、0.03709和0.04699.TNT、RDX、HMX氧化反应的活化能、指前因子和平均反应级数分别为:61.31 kJ·mol~(-1),4251,1.56.     

近临界水中4,4′-二溴联苯催化氧化降解的研究

以锰系氧化物作催化剂研究了4,4′-二溴联苯(4,4′-DBB)在近临界水中的氧化降解及反应动力学。确定了适宜的催化氧化工艺条件为物料质量比m(H2O2)∶m(4,4′-DBB)=300∶1、反应温度320℃、反应压力11.9 MPa、反应时间20 min,在此工艺条件下反应后水样的化学需氧量(COD)为32.6 mg/L,达到了GB8978—1996的排放要求。反应动力学结果表明4,4′-二溴联苯氧化反应的级数为1.71,表观活化能为37.89 kJ/mol。     

甲基肼废水的超临界/过热近临界水氧化降解研究

为使肼类燃料废水处理后达标排放,本研究利用超临界水氧化和过热近临界水氧化技术处理推进剂甲基肼废水并对比2种技术的降解效果。以COD和NH₃-N为考察指标,通过正交实验研究了反应温度、压力、时间及过氧系数对甲基肼处理效果的影响,借助高效液相色谱对比分析了不同压力下甲基肼降解率随反应时间的变化过程,探讨了超临界水氧化和过热近临界水氧化状态下水的主要物性参数变化,并从化学平衡的角度探讨了自由基氧化反应速率的变化。结果表明,当温度为550℃、过氧系数为5、反应时间为4 min时,超临界水氧化状态(24 MPa)和过热近临界水氧化状态(18 MPa)下COD和NH₃-N的处理效果均可达标;2种状态的反应进程不同,过热近临界水氧化状态主要受化学反应平衡移动的影响,超临界水氧化状态主要受高效传热和传质的影响,过热近临界水氧化状态处理肼类燃料废水更经济。     

响应面法优化催化超临界水氧化法处理制药废水的研究

采用超临界水氧化法处理制药废水,考察温度、压力、停留时间、过氧量等因素对废水COD去除效果的影响;采用响应面分析法对实验结果进行数据分析和参数优化.结果表明,在最佳操作点温度压力25 MPa,392.54℃,氧化剂过量1.254倍,停留时间52.58 s的条件下,COD去除率达到最高值（98.92％）.     

响应面法优化Fenton氧化处理高浓度废乳化液

采用Fenton氧化法对高浓度废乳化液处理进行了研究,基于Box-Behnken响应面法,考察了初始pH、FeSO_4·7H_2O加入量、H_2O_2加入量的单独作用和交叉作用,并建立了COD去除率数学模型,结果表明:影响因子显著性FeSO_4·7H_2O加入量初始pHH_2O_2加入量,初始pH与H_2O_2加入量的交叉作用显著;数学模型回归性较好,预测最佳COD去除率为89.46%。确定了Fenton氧化最佳条件为:初始pH为4.1,FeSO_4·7H_2O加入量为22 mmol/L,H_2O_2加入量为636 mmol/L,验证试验结果为89.11%,与拟合的二次回归模型预测值基本相符。     

亚临界水萃取紫草中左旋／右旋紫草素的工艺优化

研究了亚临界水萃取技术富集紫草中左旋/右旋紫草素的工艺过程,采用响应曲面法对影响紫草素提取率的工艺参数进行分析优化.考察了萃取温度、萃取时间和固液比对紫草素提取率的影响,结果发现三个因素在各自考察的实验范围内均有显著影响.采用可见分光光度法对亚临界水提取液中紫草素的浓度进行分析,在510 nm波长下测得的标准线性方程为y=24.77x+0.0311,相关系数为0.9905,紫草素浓度的线性范围是0.0084～0.0540 mg·mL-1.响应曲面分析模型预测的最佳提取条件是:固液比为7.875 g·L-1,在20 MPa、117.5℃下提取18 min,此时紫草素最大提取率是2.02 mg·g-1,与模型预测值基本相符.采用亚临界水萃取紫草素具有高效、环保、操作简便等优势,利用响应曲面设计能够有效地优化萃取过程,为该技术的推广提供了一定的理论支持.     

SCWO处理轮胎裂解脱硫废液的响应面法优化

采用超临界水氧化(SCWO)法处理废旧轮胎热解过程中产生的脱硫废液,利用响应面法对处理过程中的主要影响因素进行了优化,并通过中心复合设计(CCD)建立了COD去除率的二次回归模型。将实测值与根据模型计算的预测值进行对比,结果表明,以模型代替真实实验点对实验结果进行分析具有较高的可靠性。     

响应面法优化丁香精油的超临界萃取工艺

采用单因素试验及响应面法对超临界CO2萃取丁香精油进行工艺优化.选取萃取温度、萃取压力及萃取时间作为考察因素,以丁香精油收率为考察指标进行单因素试验.依据单因素试验结果确定最佳萃取温度、萃取压力及萃取时间,采用响应面法进行3因素3水平试验,考察3因素及其交互作用对丁香精油收率的影响.结果表明:超临界CO2萃取丁香精油的最优工艺为萃取温度49℃、萃取压力36 MPa、萃取时间105 min、CO2流量为10 kg·h-1,最优工艺下丁香精油平均收率为20.1％.通过试验验证,此法可靠,可以用于超临界CO2萃取丁香精油工艺的初步分析及优化.     

Waste water treatment by solvent extraction

A review is presented of the application of solvent extraction to the treatment of waste waters. Methods of extraction, solute-solvent separation and water — solvent separation are described. Phenol removal, oily water treatment, desalination, metal recovery by “liquid ion exchange” and miscellaneous other applications are described/ Available economic data are discussed. Possible future applications are outlined and it is suggested that greatest potential is in the treatment of oily waste water and of relatively concentrated streams containing valuable or noxious materials     

Anodic oxidation of phenol for waste water treatment

The electrochemical oxidation of phenol for waste water treatment applications was investigated on lead dioxide packed-bed anodes. Cells were operated in both batch and continuous modes with feed streams up to 1100 nig/1 phenol dissolved in aqueous solutions of Na₂SO₄ and H₂SO₄ or NaOH. All the phenol in solution could be readily oxidized but complete total organic carbon (T.O.C.) removal was more difficult. The percent phenol oxidized increased with increasing current density, and decreased as initial phenol concentration, electrolyte flow rate, pH and anode particle size were increased. Results are compared to simple mathematical models.     

Anodic oxidation of aniline for waste water treatment

The electro-oxidation of dilute aqueous solutions of aniline was studied on a lead dioxide packed bed anode. The anolyte consisted of 400 ml of 5.5 mM aniline in dilute sulphuric acid. The anolyte was recirculated through a packed bed electrochemical reactor with an anode compartment volume of 5.0, at various flowrates. The concentrations of aniline, benzoquinone, maleic acid and carbon dioxide were measured against time for experiments ranging from 0.5 to 5.0h in duration. The effects of applied current, pH, flowrate and initial aniline concentration on the percentage of aniline oxidized and carbon dioxide produced are discussed. Aniline in the solution oxidized readily, but further oxidation of intermediates to carbon dioxide was more difficult. The percentage of aniline oxidized increased with increasing current density, while it decreased with increasing initial aniline concentration and pH. Current efficiencies ranged from 15 to 40% for complete oxidation of aniline to CO₂.     

Anodic oxidation of phenol for waste water treatment

The electrochemical oxidation of phenol for waste water treatment was studied at a platinum anode. Analysis of reaction intermediates and a carbon balance has shown that the reaction occurs by two parallel pathways; chemical oxidation with electrogenerated hydroxyl radicals and direct combustion of adsorbed phenol or/and its aromatic intermediates to CO₂.     

Anodic oxidation of phenol for waste water treatment

The electrochemical oxidation of phenol for waste water treatment applications was investigated on lead dioxide packedbed anodes. Cells were operated in both batch and continuous modes with feed streams up to 1100 mg/l phenol dissolved in aqueous solutions of Na₂SO₄ and H₂SO₄ or NaOH. All the phenol in solution could be readily oxidized but complete total organic carbon (T.O.C.) removal was more difficult. The percent phenol oxidized increased with increasing current density, and decreased as initial phenol concentration, electrolyte flow rate, pH and anode particle size were increased. Results are compared to simple mathematical models.     

Subcritical water extraction of bioactive compounds from Radix Puerariae and optimization study using response surface methodology

Subcritical water extraction (SWE) of bioactive extracts from Radix Puerariae (RP) was firstly optimized by response surface methodology (RSM) and its extraction efficiency was compared with two traditional volatile isolation methods including hot water extraction (HWE) and ethanol reflux extraction (ERE). The optimal SWE parameters were as follows: extraction temperature of 141?°C, extraction time of 58?min, and liquid-solid ratio l of 23:1?mL/g. Under these conditions, yield of bioactive extracts was 28.9?±?0.2%, which was slightly higher than that obtained by ERE, and more than two-fold the value obtained by HWE respectively. Isoflavones and polysaccharide content in SWE was significantly higher than that of HWE and slight lower than that of ERE. The results indicated that SWE could be a productive and environmental friendly technique for extracting bioactive extracts from RP.     

催化氧化法处理含硫废水的研究

硫化物是煤化工废水常见的污染物之～,现有多种处理方法,其中空气氧化法以成本低、效果较好而备受重视,但存在反应速率慢、硫化氢逸出等缺点。从3种非均相催化剂中选出效果最佳的PT-OC01催化剂,以硫化物的去除率和硫化氢逸出率为指标,设计正交实验,找出最佳的工艺条件。实验结果表明,硫化物去除率可达87．3％,硫化氢逸出率仅为0．25％。     

Catalytic supercritical water oxidation of tri-n-butyl phosphate: Process optimization by response surface methodology and cytotoxicity assessment

Catalytic supercritical water oxidation (SCWO) of an organophosphate flame retardant, namely tri-n-butyl phosphate (TNBP) was studied. Firstly, copper oxide nanoparticles (NPs) were synthesized in SCW and their properties were characterized by various analyses. Afterwards, their catalytic performance was investigated under different conditions including reaction temperature (400–500 °C), TNBP volume percentage in the feed (1–4%), oxidant ratio (0–2) and reaction time (50–150 min) based on response surface methodology (RSM). The synthesized CuO NPs had an average particle size of 30 nm with a narrow distribution. According to RSM analysis, the reaction temperature and time are the most significant factors; whereas, the impact of the other factors, especially TNBP volume percentage in the feed, was found to be negligible. Overall, excellent performance was achieved under optimal conditions found by the RSM, which was reaction temperature of 500 °C, TNBP volume percentage of 4%, oxidant ratio of 1.5, and reaction time of 90 min. The TOC removal efficiency as an indicator of TNBP degradation was about 99%. Finally, in vitro cell viability assays for the cytotoxicity evaluation of fresh and SCW-treated solution were applied. The results of MTT showed that SCWO converts TNBP into by-product that did not induce any cytotoxicity.