Computational fluid dynamics simulation of formaldehyde emission characteristics and its experimental validation in environment chamber

We investigated the effect of supply air rate and temperature on formaldehyde emission characteristics in an environment chamber. A three-dimensional computational fluid dynamics （CFD） chamber model for simulating formaldehyde emission in twelve different cases was developed for obtaining formaldehyde concentration by the area-weighted average method. Laboratory experiments were conducted in an environment chamber to validate the simulation results of twelve different cases and the formaldehyde concentration was measured by continuous sampling. The results show that there was good agreement between the model prediction and the experimental values within 4.3% difference for each case. The CFD simulation results varied in the range from 0.21 mg/m3 to 0.94 mg/m3, and the measuring results in the range from 0.17 mg/m3 to 0.87 mg/m3. The variation trend of formaldehyde concentration with supply air rate and temperature variation for CFD simulation and experiment measuring was consistent. With the existence of steady formaldehyde emission sources, formaldehyde concentration generally increased with the increase of temperature, and it decreased with the increase of air supply rate. We also provided some reasonable suggestions to reduce formaldehyde concentration and to improve indoor air quality for newly decorated rooms.     

氮掺杂TiO2改性涂料的制备及其对甲醛光催化降解性能研究

以Ti（SO4）2为原料,采用氨水水解法制备氮掺杂二氧化钛前驱体,煅烧得到氮掺杂二氧化钛纳米粉体,作为功能活性组分．利用FT-IR红外光谱和激光粒度等方法对所制备的活性组分进行表征．将功能活性组分分散到水性乳胶涂料体系中,通过高速搅拌使其均匀分散,制得改性乳胶涂料．以30w日光灯管为光源,用甲醛降解反应考察了复合乳胶涂料的光催化活性．结果表明,复合了该活性组分的乳胶涂料具有优良的光催化净化空气的性能．N掺杂量对其光催化活性有较大的影响,当氮的掺杂量为0．7wt％,七天后光催化甲醛降解率达到最高92％．     

改性三聚氰胺甲醛树脂的合成

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固体酸催化合成亚甲基双丙烯酰胺的实验研究

在固体酸催化剂和阻聚剂存在下,反应温度55-60℃,水解的丙烯腈与甲醛溶液作用,合成N．H^1—亚甲基双丙烯酰胺,讨论了各种因素对产品收率和纯度的影响,该法产品的收率高达88％,大大缩短了反应周期,减少了副产物的生成。     

When Glass and Metal Corrode Together,VI: Chalconatronite

ABSTRACT

Chalconatronite, Na₂[Cu(CO₃)]₂·3H₂O, is formed as a corrosion product when copper alloys are exposed to sodium carbonate solutions in the air. This also happens when metals come into contact with corroding soda glass which forms alkaline surface films in reaction with humidity from clean air. More often, substantial amounts of formaldehyde are present indoors which react to formate via the Cannizzarro reaction and accumulate over time in the films. Twenty cases of chalconatronite (including two mentioned in the literature) are reported as occurring on heritage objects with glass in contact with copper alloys: Baroque reliquaries with set glass gems, enamel on metal (sixteenth century and a modern replica of intentionally unstable composition), Christmas tree glass baubles with wires, glass buttons with metal shanks, a glass figure with a wire support, miners’ lamps, and a glass framed daguerreotype. These confirmed identifications might help conservators in investigating similar cases to shed more light on the formation conditions.     

食品中甲醛的存在及危害

简要介绍了食品中甲醛含量，尤其是在食品中人为添加甲醛的危害及控制。     

甲醛等挥发性物质对大鼠的亚慢性毒性实验

文章研究了不同剂量甲醛等挥发性物质对发育期大鼠体重、血液常规指标、肝肾功能的影响。研究结果表明：甲醛等挥发性物质的混合物能显著降低大鼠体重,而对肝、肾重量无明显影响;可明显提高大鼠血液中血小板（PLT）和嗜酸性粒细胞（EOS）的含量,但对血液中其它常规指标无明显影响;能明显提高大鼠血清中的谷丙转氨酶（ALT）和天冬氨酸氨基转移酶（AST）的活性．对血清中碱性磷酸酶（ALP）、γ-谷氨酰转肽酶（GGT）、血尿素氮（BUN）和肌酐（Cr）无明显影响。     

耐水和低游离甲醛脲醛树脂的合成与改性

为寻求合适的工艺条件以提高脲醛树脂胶粘剂的综合性能,采用了降低甲醛/尿素物质的量比、改进合成工艺、加入改性剂等3种途径优化了脲醛树脂的合成方法.实验结果表明:以甲醛和尿素为单体,添加适量的聚乙烯醇和三聚氰胺改性剂,甲醛和尿素最佳物质的量比约为1.5:1,尿素分3次(11.4 g、0.5 g、0.2 g)投料,反应温度控制在(35℃-85℃),反应时间约60min,用聚乙烯醇和三聚氰胺进行改性,可制得综合性能较好的低毒耐水脲醛树脂胶粘剂.产品质量达到国家相关规定指标.     

催化动力学荧光法测定痕量甲醛

在稀硫酸介质中,甲醛对溴酸钾氧化中性红的反应具有较强的催化作用,使其荧光强度降低.据此,建立了催化动力学荧光法测定痕量甲醛的新方法.其检出限为6.59×10-8g.L-1,线性范围为0~0.128mg.L-1.该法简便、快速,可用于测定未知溶液中的甲醛.     

中低氮呋喃树脂的合成

根据实际生产的需要研究合成了含氮3％以下的脲醛改性呋喃树脂,确定了工艺条件,经筛选加入的添加剂不仅降低树脂中游离甲醇的含量,而且使树脂的强度有所增加．