酚试剂分光光度法测定低浓度甲醛关键影响因素

甲醛是主要的室内污染物，严重危害人体健康。准确测量甲醛，特别是低浓度甲醛的含量，对于室内甲醛的浓度测量和污染治理，具有不可替代的重要意义。酚试剂分光光度法检测甲醛具有试剂成本低、操作简单等优点，而且检出限、灵敏度、抗干扰程度等综合性能较好，是应用最多的甲醛检测方法。本研究采用国标GB/T 18204.2—2014推荐的酚试剂分光光度法检测甲醛的实验步骤为参考依据，采用控制变量法分别对盐酸、酚试剂、硫酸铁铵等试剂用量，温度、波长、时间等显色条件，以及硫酸铁铵溶液、酚试剂溶液稳定性等关键影响因素进行了系统考察，获得了甲醛检测的最优检测条件。并据此进行多次实验，绘制了代表性曲线，确定了该检测方法的灵敏度，测得该方法测定甲醛的检出限大约为0.061μg。     

TKO和TKB系列增粘剂在橡胶配方中的应用技术

评述了对－叔辛基苯酚甲醛树脂系列和对－叔丁基苯酚甲醛树脂系列增粘剂在干混胶料、胶浆和压敏胶中的配合技术。特别介绍了国际上所进行的操作油，增粘剂，炭黑、硫黄等助剂以及氧，湿度、湿度、温度，混炼等工艺条件对胶料粘性影响的一些研究成果。     

双氰胺甲醛絮凝剂处理印染废水的研究

选用自制的双氰胺甲醛作为絮凝脱色剂处理高浓度印染废水，并与碱性氧化铝和硫酸亚铁作了对比实验。考察了投加量、原水pH值、搅拌时间等因素对絮凝效果的影响。实验结果表明在用量较少并且其它操作条件相同的情况下，双氰胺甲醛具有很好的絮凝脱色效果及COD去除率。在最佳的操作条件下(投加量200mg／L，pH=11～13，搅拌时间1．5min)，双氰胺甲醛脱色率为99％，COD去除率达到73．1％，减轻了后续处理难度。     

干香菇中甲醛含量的测定

利用甲醛与乙酰丙酮生成稳定的黄色化合物,在412nm波长下测定其吸光度,根据吸光度与甲醛浓度之间的线性关系,检测干香菇中甲醛的含量。对乙酰丙酮法测定甲醛含量的最佳试验条件进行了探讨,操作简便,性能稳定。     

用焦化二甲苯合成XF树脂的研究

以焦化二甲苯为原料，甲醛为连接剂可合成线性结构的二甲苯甲醛树脂。试验筛选出了最佳的工艺路线与操作条件，探讨了ＸＦ树脂的分子结构、平均分子量等参数与反应条件的关系，为焦化产品的深加工开辟了新路。     

痕量甲醛快速检测的荧火分光光度法研究

建立了荧光分光光度法快速检测洗涤剂中痕量甲醛的方法，在最佳实验条件下，甲醛浓度在0.1-1.0μg/ml范围内呈良好的线形关系，线形回归方程为F=0.3333 16.9212C.与其它甲醛测定法相比，该法操作简便检测速度快，应用于实际洗洁精样品中甲醛含量的测定，结果令人大满意。     

甲醛法测定大气中二氧化硫方法实验条件的探讨

甲醛缓冲溶液吸收—盐酸副玫瑰苯胺分光光度法(简称甲醛法),该方法具有毒性小、灵敏度高、吸收效率高的优点。但由于甲醛法操作要求严格,步骤繁琐,且测定结果的准确性容易受实验条件控制因素的影响。笔者通过多次反复实验,发现改进部分实验条件,不仅能够保证测定结果的准确性,而且更易操作。本文对甲醛法中显色实验条件等因素进行进一步的探讨。     

碱水浓度对娃娃菜甲醛残留量的影响

研究了不同时间和温度条件下，用自来水浸泡、盐水浸泡和碱水浸泡下对娃娃菜中甲醛残留量的影响。通过实验找出有效、易操作的方法来降低娃娃菜中的甲醛含量。采用高效液相色谱法对经过不同方法处理的娃娃菜中的甲醛残留量进行分析，结果显示：自来水浸泡、盐水浸泡、碱水浸泡均能不同程度地去除娃娃菜中残留的甲醛，从甲醛去除率及营养价值等方面考虑，选择自来水浸泡的料液比为1∶5、盐水浓度为2%、碱水浓度为5%、自来水的浸泡时间为45 min、盐水和碱水的浸泡时间为30 min、温度均为30℃，在此条件下，盐水浸泡和碱水浸泡的效果好于自来水浸泡，且盐水浸泡的效果好于碱水浸泡，其中，盐水浸泡处理的甲醛去除率为98.11%。     

控制开车条件及甲醛生产“三期”反应温度的探讨

在甲醛实际生产中，就控制开车条件及“三期”反应温度和提高产量、节能降耗、延长触媒使用寿命的关系，提出了可操作方案。     

水蒸汽蒸馏法测定水性胶粘剂中游离甲醛的含量

主要研究用水蒸汽蒸馏法进行样品处理，用乙酰丙酮分光光度法测定样品中游离甲醛的含量。对用水蒸汽蒸馏和未用水蒸汽蒸馏的甲醛标准曲线进行比较，两曲线几乎相同，其线性范围为1—40峭，相关系数为0．9998，在蒸馏水及水性胶粘剂中进行加标回收试验，平均回收率分别为96．2％和96．9％，对水性胶粘剂样品中甲醛含量的测定，结果的相对标准偏差为1．21％，并讨论了该方法的最佳实验条件，在pH=6、波长413nm的条件下，有较好的吸收峰。该方法操作简单、实用性强，具有较高的精密度和准确度。     

Methanol oxidative dehydrogenation in a catalytic packed-bed membrane reactor: experiments and model

Methanol oxidative dehydrogenation to formaldehyde over a Fe-Mo oxide catalyst was studied experimentally in three reactor configurations: the conventional fixed-bed reactor (FBR) and the packed-bed membrane reactor (PBMR), with either methanol (PBMR-M) or oxygen (PBMR-O) as the permeating component. The kinetics of methanol and formaldehyde partial oxidation reactions were determined independently from FBR experiments. A steady state plug-flow PBMR model, utilizing these kinetics and no adjustable parameters, fit the experiments accurately. It is shown experimentally and in accordance with the model that for given overall feed conditions, the reactor performance for methanol conversion and formaldehyde yield is in the order PBMR-M < FBR < PBMR-O.     

球载纳米TiO_2光催化氧化低质量浓度甲醛

采用玻璃珠作为纳米TiO2光催化剂载体,应用填充式光催化反应器,对低质量浓度甲醛进行光催化降解。研究不同甲醛质量浓度、反应温度、湿度下,甲醛转化率及反应速率变化情况。研究结果表明,0.095 g光催化剂即可使20 mg/m3甲醛转化率达到61.3%。随甲醛质量浓度升高,甲醛转化率呈先降低后升高趋势,反应速率随质量浓度的升高而升高,基本符合Langmuir-Hinsherwood模型。随温度升高,甲醛反应速率降低,反应温度对低质量浓度甲醛影响较小。甲醛反应速率随湿度升高先下降,相对湿度高于30%时,基本不再变化。反应产物主要为CO2,温度高于115℃时,参与反应的甲醛可全部转化为CO2。     

Improving selectivity during methane partial oxidation by use of a membrane reactor

A reactant-swept catalytic membrane reactor for partial oxidation of methane to formaldehyde has been modeled. Kinetic parameters were taken from the literature for a V₂O₅/Sio₂ methane partial oxidation catalyst, and membrane parameters characteristic of commercially available materials were used. The models show that the selectivity for formaldehyde can be significantly improved by using a membrane reactor.     

Formaldehyde biodegradation in the presence of methanol under denitrifying conditions

Simultaneous formaldehyde and methanol biodegradation and also denitrification were studied in batch assays and in a continuous laboratory‐scale reactor. In batch assays, high formaldehyde concentrations (up to 1360 mg dm^?3) were removed under anoxic conditions in the presence of methanol. It was found that formaldehyde biodegradation produced methanol and formic acid as products. The denitrification process was affected by the initial formaldehyde concentration. In the continuous reactor, the biodegradation of different concentrations of formaldehyde (1500–275 mg dm^?3) and methanol (153–871 mg dm^?3) took place, maintaining the organic loading rate at 0.84 g COD dm^?3 d^?1 (COD/N 4). However, each increase in the methanol concentration in the influent caused a decrease in the denitrification level. An adaptation period to methanol was necessary before the denitrification percentage could be recovered. In contrast with batch assays, in the continuous reactor methanol and formic acid were not detected in the effluent. Moreover, in the continuous reactor the denitrification percentages were higher and the nitrite accumulation was lower. Copyright © 2005 Society of Chemical Industry     

Synthesis and cure kinetics of liquefied wood/phenol/formaldehyde resins

Wood liquefaction was conducted at a 2/1 phenol/wood ratio in two different reactors: (1) an atmospheric three‐necked flask reactor and (2) a sealed Parr reactor. The liquefied wood mixture (liquefied wood, unreacted phenol, and wood residue) was further condensed with formaldehyde under acidic conditions to synthesize two novolac‐type liquefied wood/phenol/formaldehyde (LWPF) resins: LWPF1 (the atmospheric reactor) and LWPF2 (the sealed reactor). The LWPF1 resin had a higher solid content and higher molecular weight than the LWPF2 resin. The cure kinetic mechanisms of the LWPF resins were investigated with dynamic and isothermal differential scanning calorimetry (DSC). The isothermal DSC data indicated that the cure reactions of both resins followed an autocatalytic mechanism. The activation energies of the liquefied wood resins were close to that of a reported lignin–phenol–formaldehyde resin but were higher than that of a typical phenol formaldehyde resin. The two liquefied wood resins followed similar cure kinetics; however, the LWPF1 resin had a higher activation energy for rate constant k₁ and a lower activation energy for rate constant k₂ than LWPF2. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

净化室内甲醛污染的研究进展

甲醛作为室内污染物,严重危害人体健康。主要分析比较了几种常见的甲醛治理方法,为进一步研究甲醛降解提供理论依据,也为高效甲醛净化反应器的研制奠定研究基础。     

Aflatoxin inactivation: Treatment of peanut meal with formaldehyde and calcium hydroxide

A peanut meal contaminated with ca. 600 ppb aflatoxins was treated with formaldehyde alone and in combination with calcium hydroxide in a benchscale reactor, operated both sealed and at atmospheric pressure. In general, thin layer chromatographic assays revealed that addition of calcium hydroxide to formaldehyde caused greater inactivation of the toxins than did formaldehyde alone. With the reactor sealed and 25% moisture in the meal, treatments for 1 hr with 0.5% and 1.0% formaldehyde plus 2.0% calcium hydroxide yielded products having 3 and 1 ppb aflatoxins, respectively, whereas under reflus at atmospheric pressure with 20% meal moisture, 1 hr treatment with 1.0% calcium hydroxide yielded a product with 5 ppb aflatoxins. Deceased.     

催化转化-生物降解法处理高浓度甲醛废水

提出了催化转化-生物降解法处理高浓度甲醛废水的新方法。研究发现,在温度为70℃,催化转化剂与甲醛摩尔比为1∶5,反应30 min,废水中甲醛去除率可达99.96%。预处理后的甲醛废水BOD5/CODcr值由0.12升至0.50,甲醛浓度<3 mg/L,大大提高了废水的可生化性。实验结果还表明,在采用生物降解法处理预处理后的甲醛废水过程中,当温度为35~40℃,pH值为7.0~7.5,水力停留时间(HRT)为9~12 h时,厌氧反应器有机负荷(OLR)为8.0~10.0 kg/(m3.d),好氧反应器OLR为1.0~2.0 kg/(m3.d),CODcr总去除率达到98.81%,出水COD<100 mg/L。该方法具有工艺简单、处理效率高和成本低等特点,有极高的实际应用价值。     

甲缩醛氧化制甲醛固定床反应器的数学模拟

依据甲缩醛氧化制甲醛的宏观动力学模型和固定床拟均相二维模型，采用正交配置法模拟固定床单管反应器，模拟结果与试验数据基本一致，表明该反应器数学模型具有一定的可靠性和实用性。用此模型进一步考察了主要操作条件，催化剂稀释比和床展稀释长度对甲醛收率和热点温度的影响，为该过程的工业放大和反应器设计提供了依据。     

Selective Oxidation of Methanol to Formaldehyde Using Modified Iron-Molybdate Catalysts

Methanol selective oxidation to formaldehyde over a modified Fe-Mo catalyst with two different stoichiometric (Mo/Fe atomic ratio = 1.5 and 3.0) was studied experimentally in a fixed bed reactor over a wide range of reaction conditions. The physicochemical characterization of the prepared catalysts provides evidence that Fe₂(MoO₄)₃ is in fact the active phase of the catalyst. The experimental results of conversion of methanol and selectivity towards formaldehyde for various residence times were studied. The results showed that as the residence time increases the yield of formaldehyde decreases. Selectivity of formaldehyde decreases with increase in residence time. This result is attributable to subsequent oxidation of formaldehyde to carbon monoxide due to longer residence time.