净化空气矿棉板的制备及其净化甲醛性能研究

采用光触媒改性的涂料刷涂于矿棉板基板表面,制成一种净化空气矿棉板.以甲醛为去除对象,用静态方法,考察了净化空气矿棉板的净化性能,同时分析了甲醛初始量、相对湿度、温度对净化效率的影响.结果表明,涂料中光触媒的质量分数和涂料的涂刷量都对矿棉板的净化性能有显著影响:在30W日光灯照射下,维持温度21℃,相对湿度60%,甲醛原液注入量为10μL,净化空气矿棉板对甲醛的净化效率可达96.3%;降解效率随甲醛滴入量增加而增大.该矿棉板能有效去除甲醛,且性能稳定,适用于室内有害气体净化.     

温度对刨花板甲醛散发的影响

本文通过实验研究了温度对刨花板甲醛散发的影响。结果表明，随着外界温度升高，刨花板甲醛散发的能力增强。作者就如何从控制温度的观点出发，降低刨花板的甲醛散发量提出了一些建议。     

温度对材料污染散发和室内空气甲醛浓度影响的分析

环境温度对装修引起的室内空气污染浓度有显著的影响。本文通过环境气候箱实验测试温度与甲醛污染释放率的关系,及对材料污染释放特性参数初始可散发浓度C_0、扩散系数D_m和分离系数K的影响;同时通过实际精装住宅工程的室内空气甲醛浓度测试,提出了室内空气甲醛浓度C与温度T的经验关系式,为建筑室内污染物控制设计和验收时考虑温度影响提供可行的计算方法。     

温度变化对板材内VOC散发特性影响的研究

扩散系数及分配系数受温度的影响,为系统地研究温度对VOC散发的影响,本文建立了基于传热传质理论下板材内VOC散发的连续模型,并用该模型对常用板材中VOC的散发进行分析.模拟结果同计算的理论值以及实验数据均能较好的吻合.当温度从18℃升高到50℃时,不论是初始时刻的VOC散发速率还是散发稳定时刻的浓度值,都有明显的升高,散发24小时后,板材在50℃下的散发量约为30℃下散发量的2.5倍;同时本文对环境温度tf波动情况下的VOC散发结果模拟表明:空气中污染物在材料表面表现出沉降与二次挥发的现象.对密闭小室中板材内部VOC分布的模拟结果表明,随着散发时间的推移,材料内部的污染物浓度将逐渐趋于均匀.     

微波处理法降低中密度纤维板甲醛释放量的试验研究

基于响应面法分析了微波处理温度、处理时间及输入功率对中密度纤维板(MDF)试件甲醛释放量下降率(DRF)的影响规律.结果表明:提高微波处理温度以及在高温下延长微波处理时间或在低温下增大输入功率都可以增大试件DRF.但是,当处理温度较高时,输入功率的增加反而会使微波处理效果变差.在处理温度60℃,处理时间40min以及输入功率317W时的微波处理效果最好,此时MDF试件的甲醛释放量下降率为59.31%,且其主要力学性能下降轻微.     

家具甲醛散发量测试研究

建立了一种不同于现行木家具标准的测试方法,利用30m3大型空气质量测试舱,模拟家具的实际使用环境对几类不同材质的家具在散发稳定阶段的单位面积甲醛释放量进行了测试.分析了不同材质的家具的散发规律、稳定阶段的单位面积散发量.最后讨论了本文提出的家具的测试方法及测试指标在实际工程中的应用价值.     

粉煤灰沸石分子筛对室内空气甲醛净化性能的实验研究

沸石分子筛具有吸附效率高、环境友好、使用寿命长等优点,在室内甲醛净化领域中作为吸附剂得到了普遍应用,本文以废弃的粉煤灰为原料,通过碱熔融-水热法自制廉价的粉煤灰沸石分子筛,以此作为吸附材料对室内空气进行甲醛净化性能的测试。研究不同空气温度、相对湿度、空气流动速度及不同甲醛含量对室内空气甲醛净化的影响。结果表明,降低室内空气温度、适当的增加湿度以及合理控制空气流速有利于强化室内甲醛气体净化效果。当吸附温度为12℃时,甲醛的吸附量最大为1.36 mg/g;当相对湿度为40%时,甲醛的吸附量最大为1.25 mg/g;当空气流速为4 m/s时,吸附效率最大为0.675 mg/(g·h);当甲醛含量为0.75 mg/g时,甲醛气体的脱除率最大为83%。     

家具甲醛散发量测试研究

建立了一种不同于现行木家具标准的测试方法，利用30m。大型空气质量测试舱．模拟家具的实际使用环境对几类不同材质的家具在散发稳定阶段的单位面积甲醛释放量进行了测试。分析了不同材质的家具的散发规律、稳定阶段的单位面积散发量。最后讨论了本文提出的家具的测试方法及测试指标在实际工程中的应用价值。     

2010—2014年祁连山老虎沟流域高寒草甸蒸散发变化特征

为估算祁连山老虎沟流域高寒草甸的蒸散发量,利用2010—2014年老虎沟流域自动气象站观测数据,采用Penman-Monteith(P-M)公式首先计算了单点的蒸散发量,再利用Landsat8遥感数据,结合能量平衡系统(SEBS)模型估算了典型晴天条件下流域的蒸散发量,并将估算结果与P-M公式估算结果进行了对比分析。结果表明:研究区高寒草甸5a年蒸散发总量变化幅度较大,平均为205.4mm;各生长阶段蒸散发总量与日均值大小顺序均表现为生长中期>生长后期>生长初期;蒸散发量在7月中旬之前较低,7月中旬之后直到8月下旬最高,8月下旬到生长期结束下降。整个流域的典型晴天遥感日平均蒸散发呈现冰川表面<草地<裸土裸岩石砾地<水域的特征。敏感性实验显示,蒸散发量对相对湿度、净辐射较敏感。     

高密度人造木地板的VOCs散发实验研究

针对目前室内装修常用的高密度人造木地板，采用大环境舱模拟实际室内空气环境研究了甲醛的散发，并对处于稳定散发期的木地板研究了环境因素对其甲醛及VOCs散发的影响，同时作了VOCs化学成分的检测。研究结果发现：高密度人造木地板的甲醛散发具有规律性，甲醛散发在几小时内达到最大值后逐渐衰减直到趋于稳定值；环境因素对稳定散发期的术地板的甲醛及VOCs的散发有较大影响；受试木地板除散发甲醛外还散发多种VOCs，它们主要是芳香族挥发性有机化合物。     

Formaldehyde and acetaldehyde exposure mitigation in US residences: in‐home measurements of ventilation control and source control

Measurements were taken in new US residences to assess the extent to which ventilation and source control can mitigate formaldehyde exposure. Increasing ventilation consistently lowered indoor formaldehyde concentrations. However, at a reference air exchange rate of 0.35 h^?1, increasing ventilation was up to 60% less effective than would be predicted if the emission rate were constant. This is consistent with formaldehyde emission rates decreasing as air concentrations increase, as observed in chamber studies. In contrast, measurements suggest acetaldehyde emission was independent of ventilation rate. To evaluate the effectiveness of source control, formaldehyde concentrations were measured in Leadership in Energy and Environmental Design (LEED)‐certified/Indoor airPLUS homes constructed with materials certified to have low emission rates of volatile organic compounds (VOC). At a reference air exchange rate of 0.35 h^?1, and adjusting for home age, temperature and relative humidity, formaldehyde concentrations in homes built with low‐VOC materials were 42% lower on average than in reference new homes with conventional building materials. Without adjustment, concentrations were 27% lower in the low‐VOC homes. The mean and standard deviation of formaldehyde concentration was 33 μg/m³ and 22 μg/m³ for low‐VOC homes and 45 μg/m³ and 30 μg/m³ for conventional.     

Effects of Climatic Parameters on Formaldehyde Concentrations in Indoor Air

The results of measurements of indoor air formaldehyde concentrations in occupational and private residences are presented for the period 1986 to 1993, based on requests of persons who complained about irritations. In many cases, climatic parameters such as the air exchange rate, temperature and relative humidity were also monitored. Calculated mean values for temperature and humidity were 22°C and 45% respectively. The average air exchange rate was 0.36 h^?1, which is well below a recommended guideline value of 0.8 h?' and it was evident that the ventilation is clearly insufficient in many rooms. The average formaldehyde concentration was 119 μg/m ^?3 (252 data), which is only slightly below the German guideline value of 125 μg/m ^?3. In 31% of the cases this guideline was exceeded. As expected, a clear relation between formaldehyde concentrations and the air exchange rate was found. The highest levels result at AE≤0.8 h^?1, but only a single value exceeds 125 μg/m ^?3 at AE≥0.8 h^?1. The association of law ventilation rates with high formaldehyde levels is also evident from a comparison with theoretical data after normalization to AE=0.8 h^?1, using the Hoetjer-equation. It was also observed that the calculated annual mean concentrations decreased from 1986 to 1993.     

Emission behavior of formaldehyde and TVOC from engineered flooring in under heating and air circulation systems

Formaldehyde and volatile organic compounds (VOCs) from the adhesive, flooring, and flooring with adhesive were measured using a desiccator, a 20-L chamber and a field and laboratory emission cell (FLEC). Flooring with an adhesive is similar to that used in construction was applied to a floor heating system and an air circulation system, and the surface temperature of the flooring was set to 20 °C, 26 °C and 32 °C. The rate of formaldehyde emission from the flooring was the highest at 32 °C using a desiccator and decreased with time. The formaldehyde and aldehyde emissions from the samples using a 20-L chamber and FLEC showed a similar tendency. The VOCs emission trends with the 20-L chamber and FLEC were similar. The rate of formaldehyde and TVOC emission determined using FLEC was higher than that determined using the 20-L chamber method. The flooring emitted primarily benzene, toluene, ethylbenzene, styrene, xylene, as well as some unknown VOCs. There was a strong correlation between formaldehyde and TVOC emission for the 20-L chamber and FLEC. Samples using a floor heating system showed higher formaldehyde emission than those using an air circulation system. The level of TVOC emission was higher from the samples using an air circulation system than those using the floor heating system.     

Comparison of formaldehyde emission from building finishing materials at various temperatures in under heating system; ONDOL

The objective of this research was to investigate the effect of various temperatures, room, 37 and 50 degrees C, on formaldehyde emission from floor materials, such as laminate and plywood floorings, and furniture materials, such as MDF and particleboard veneered with decorative paper foil, by desiccator's method. The temperature conditions were set up by, measuring the temperature in a Korean under heating system. To maintain an indoor air temperature of 20 degrees C, the temperature of the flooring surface was about 37 degrees C and the temperature of the cement mortar was 50 degrees C. The initial formaldehyde emission of the laminate flooring and plywood flooring was 1.44 and 0.63 mg/l, and for MDF and particleboard it was 4.73 and 4.95 mg/l, respectively. Floor materials were under E1 grade while furniture materials were under E2 grade in terms of formaldehyde emission. Because of the under heating system, the flooring materials were exposed to 37 and 50 degrees C, while the furniture materials mostly existed at room temperature. At 37 and 50 degrees C, the formaldehyde emission level of the flooring materials was already under 0.3 ppm (F level by JIS A 1460, application possibility without area limit) after 10 days and the emission had decreased further (0.03-0.10 mg/l) after 28 days. These levels are not injurious to the human body and will not cause sick house syndrome (SHS). The problem, however, is the furniture materials such as MDF and particleboard. As these materials are not exposed to high temperature (50 degrees C in this experiment) in living condition, it was still E2 grade of formaldehyde emission level at room temperature remained even after 28 days. Although there will be variations with the volume of furniture materials and the indoor conditions, furniture materials are the principal cause of indoor air quality pollution in Korean with the under heating system. PRACTICAL IMPLICATIONS: Koreans spend most of their time sitting on ONDOL (heated) floors, with their buttocks always in contact with the floor surface. The flooring materials are exposed to high temperatures (37-50 degrees C) why the effect of bake-out is rapid. The emission of formaldehyde from furniture materials are more important for the IAQ because usually MDF and particleboard of E2 grade are being used as furniture materials in Korea.     

TVOC and formaldehyde emission behaviors from flooring materials bonded with environmental-friendly MF/PVAc hybrid resins

Polyvinyl acetate (PVAc) was added as a replacement for melamine-formaldehyde (MF) resin in the formaldehyde-based resin system to reduce formaldehyde and volatile organic compound (VOC) emissions from the adhesives used between plywoods and fancy veneers. A variety of techniques, including 20-l chamber, field and laboratory emission cell (FLEC), VOC analyzer and standard formaldehyde emission test (desiccator method), were used to determine the formaldehyde and VOC emissions from engineered flooring bonded with five different MF resin and PVAc blends at MF/PVAc ratios of 100:0, 70:30, 50:50, 30:70 and 0:100. Although urea-formaldehyde (UF) resin had the highest formaldehyde emission, the emission as determined by desiccator method was reduced by exchanging with MF resin. Furthermore, the formaldehyde emission level was decreased with increasing addition of PVAc as the replacement for MF resin. UF resin in the case of beech was over 5.0 mg/l, which exceeded E2 (1.5-5.0 mg/l) grade. However, MF30:PVAc70 was 相似文献   

Determination of formaldehyde emission with field and laboratory emission cell (FLEC)--recovery and correlation to the chamber method

The formaldehyde emission from wood-based building materials is usually determined in large chambers at a defined temperature, humidity and ventilation rate. In this article, a simpler method, the Field and Laboratory Emission Cell (FLEC), is described for determination of the formaldehyde emission and it is compared with the traditional chamber method. The formaldehyde from FLEC is collected on a silicagel cartridge impregnated with 2,4-dinitrophenylhydrazine (DNPH) and analysed with HPLC. The FLEC is easier to operate, requires a smaller sample, fewer analyses and is also more flexible than the chamber method. The emissions from different parts of a sample can be measured. Another advantage is that the equipment can be used to determine the volatile organic compounds (VOCs) emission at the same time. The FLEC method gives a good correlation to the chamber method for different building products. It also gives a good recovery. An average recovery of 98% was achieved, when two different FLEC-cells were tested with known formaldehyde sources with emissions of 0.06-0.7 mg/m2h.     

浅议光度法测量人造板甲醛释放量

结合日常检测工作,着重讨论了GB/T17657-1999中光度法测量人造板中甲醛释放量的化学分析过程;标准中应明确甲醛释放量平行试验结果之间的比对值以利于实验室内部和实验室之间的比对,以及甲醛释放量试件应进行预处理,在一定温度和湿度条件下达到恒重之后再进行试验。     

Effects of moisture content on formaldehyde emission and mechanical properties of plywood

Wood is a hygroscopic material and has ability to exchange its moisture content with air. Many mechanical properties are affected by changes in moisture content below the fiber saturation point of wood. This study evaluates the formaldehyde emission and some mechanical properties of poplar and spruce plywood panels manufactured from rotary cut veneers having different moisture content by using urea–formaldehyde (UF) and modified urea formaldehyde by melamine (M+UF). Rotary cut veneers obtained from poplar and spruce logs were classified into three groups and veneers in each group were then conditioned in a climate chamber to either 4–6%, 10–12% or 16–18% moisture content. Plywood panels with three plies and in 6 mm thickness were manufactured for each group. Formaldehyde emission, shear strength, bending strength and modulus of elasticity values of plywood panels were determined. Best bonding results were obtained in plywood panels with veneers having 4–6% moisture content. Lowest mechanical properties were found for plywood panels manufactured from veneers conditioned to 16–18% moisture content. Formaldehyde emission values of poplar and spruce plywood panels decreased with increasing veneer moisture content for both glue types. Formaldehyde emission content of panels decreased with melamine addition into the urea formaldehyde glue mixture.     

The reduction of indoor air pollutant from wood-based composite by adding pozzolan for building materials

The purpose of this study was to investigate the physico-mechanical properties and characteristics on reduction of formaldehyde and total volatile organic compound (TVOC) emission from medium density fiberboard (MDF) as furniture materials with added volcanic pozzolan. Pozzolan was added as a scavenger to urea formaldehyde (UF) resin for MDF manufacture. The moisture content, density, thickness swelling, water absorption and physical properties of MDFs were examined. Three-point bending strength and internal bond strength were determined using a universal testing machine. Formaldehyde and TVOC were determined by desiccator and 20 L small chamber methods as Korean standards method. With increasing pozzolan content the physical and mechanical properties of the MDFs were not significantly changed, but formaldehyde and TVOC emissions were decreased. Because pozzolan has a rough and irregular surface with porous form, it can be used as a scavenger for MDFs without any detrimental effect on the physical and mechanical properties.     

某住宅室内装修污染物分析与控制

对当前室内装修所用到的装修材料进行了介绍,分析了室内装修材料带来的室内污染物和对人体的危害。以一套经过新装修的住宅为例,主要对卧室内的污染物种类与含量进行了测量,给出室内污染物浓度随着时间的变化情况,测量发现室内主要污染物甲醛的浓度受温度、相对湿度、天气状况等影响。针对室内污染物的散发特点与分布,合理的对装饰装修引起的室内空气污染进行控制。