高频感应耦合等离子体降解甲醛

采用外电极式感应耦合放电等离子体对甲醛废气进行处理.实验结果表明:降低甲醛初始体积分数、增大输入功率、降低气体流量将有利于甲醛的降解;在输入功率为100 W、气体流量为l L/min、甲醛初始体积分数为2.55×10-5的条件下,甲醛降解率可达99.3％.     

高频电晕放电等离子体法处理甲醛的研究

采用高频电晕等离子体法进行去除甲醛气体的试验研究.主要考察了甲醛气体处理效果与电源频率和停留时间的关系,并进行了无填料、填加亚硝酸钠填料和钛酸钡填料对甲醛气体处理效果的对比试验.结果表明,高频电晕放电等离子体法可有效地实现对甲醛气体的去除.电源频率越高,停留时间越长,甲醛的去除效果越好;在相同条件下有填料填加对甲醛气体的去除效果优于无填料填加的去除效果;钛酸钡填料优于亚硝酸钠填料的去除效果;在电源频率为55 kHz、流量0.3 m3·h-1、进口浓度12 mg·m-3钛酸钡填料存在的条件下对甲醛的去除效率接近100%.     

室内甲醛污染与控制

甲醛是室内空气污染的主要污染物之一,本文简单介绍了室内空气中甲醛污染的来源及危害,详细介绍了减少室内甲醛污染的净化措施.     

Inter-Laboratory Comparison of No2 and SO2 Generated by Dynamic Dilution System Under Laboratory Conditions: A Technical Discussion

A workshop on analytical quality control (AQC) of ambient air quality measurement methods for nitrogen dioxide (NO₂) and sulphur dioxide (SO₂) was conducted by Central Pollution Control Board (CPCB) for officials involved in National Ambient Air Quality Monitoring (NAAQM) in India. Concentrations of NO₂ and SO₂ were generated by dynamic dilution system under laboratory conditions at low and high levels and measured using static dilution system and wet chemical methods laid down by CPCB under section 16(2)(h) of the air act 1981. CPCB provided the measured values as reference values for comparing the means obtained by the officials participated from thirteen organizations. A tolerance limit of ±15% of the reference values was specified to accept the results. Generated concentrations, which were unknown to the participants, were measured using gaseous sampling assembly (Envirotech APM 411, New Delhi, India), and wet chemical methods laid down by CPCB i.e. the same methodology which is used by the organizations to generate the data of NO₂ and SO₂ in ambient air. Simultaneously, concentrations were checked by CPCB using automatic analyzers as a check on reference concentration. It is observed that results of automatic analyzers for NO₂ and SO₂ were within a tolerance of ±5% with %RSD below 3. On the other hand, results of most of the participants showed variability in the measurements with %RSD ranging between ±0.8 and ±88.6 and exceedences of means from the tolerance limit with bias ranging between 1.4 and −59%. To check the cause of high variability in the measurements obtained under identical conditions, duplicate sampling was performed by one of the participants for SO₂ at low concentration level. In this study, results of wet chemical methods, automatic analyzers and results of duplicate sampling are analysed statistically to assess the cause of high variability in the measurements. Analysis of t-test and analysis of variance (ANOVA) showed highly significant results for NO₂ and SO₂ at high concentration levels (α 0.05) and for SO₂ at both the levels (α 0.01) respectively indicating some bias is existing either in the sampling or in analytical technique. Duplicate sampling performed to check precision in parallel measurements showed high %RSD indicating the presence of systematic error in sampling technique as the same calibration factor (CF) was used to measure the concentration of duplicate samples. Statistical analysis of flow rates of duplicate sampling showed that the sampling assembly could not maintain the constant flow rate within the ±10% with that measured at the start of the sampling. This resulted in high %RSD and deviation from the reference values for the results of most of the participants, even after accepting ±15% tolerance limit. There is a need to improve and evaluate this gaseous sample collection device under laboratory conditions to generate reliable database of NO₂ and SO₂ in ambient air.     

便携式红外气体分析仪的检测

介绍了便携式红外气体分析仪的检测方案。其检测项目与指标、检测方法可为各级环境监测站及行业监测站检测同类仪器时借鉴使用。     

普通壁纸与防火壁纸热解特性的对比研究

利用热重分析仪对市场上两种壁纸(普通壁纸和防火壁纸)在不同气氛、不同升温速率条件下的热解特性进行了研究。实验结果表明:空气气氛下壁纸的失重温度区间相对N2气氛向低温区移动,总失重率增加,残碳量减少,热解更完全。随升温速率提高,壁纸的热解曲线有向高温区移动的趋势,增大升温速率使主要热解阶段初始热解温度升高,最大失重速率增加,总失重率增加,热解更完全。防火壁纸与普通壁纸相比不易分解燃烧,更有利于防火。     

VOCs走航监测:技术方法与案例应用

挥发性有机物(VOCs)来源广泛、组成复杂,是臭氧(O3)和二次有机气溶胶(SOA)的重要前体物,且其中一些组分对人体健康存在潜在威胁。VOCs的主要排放方式包括点源、面源和无组织源排放,排放过程具有瞬时性,难以控制和监测。与传统的离线监测和在线监测相比,走航监测技术具有监测范围大、响应快速、机动性强的特点,但中国VOCs的走航监测研究还鲜有报道。该研究通过使用装载了单质谱分析仪与便携式气相色谱-质谱联用仪(GC-MS)的走航车对珠三角沿海城市某工业集聚区进行VOCs走航监测,走航过程中对环境空气中的TVOCs进行快速监测并对TVOCs质量浓度高值点进行采样及VOCs组分的成分和浓度分析。该次走航共监测到32种优控污染因子和CW加油(加气)站、JH加油站、G空调电器生产企业的两器车间及南门货场等多个TVOCs质量浓度高值点,并通过分析进一步判断VOCs排放源。结合监测结果和实地调研推断:加油站的VOCs高值主要来源于油气挥发及机动车尾气排放;G空调企业的VOCs高值则主要来源于两器车间的喷涂、烘干、洗网工序及厂区内的机动车尾气排放。尽管VOCs走航监测技术目前还存在一定不足,该方法的应用能够为掌握区域VOCs污染现状及分布特征提供新的技术手段,为实现VOCs精细化管控提供新的思路。     

北京市公共场所室内甲醛浓度水平分析

为了解北京市公共场所室内甲醛污染水平及影响因素,在工作日和周末上下午对北京市内家具市场、综合商场和服装批发市场3类公共场所不同功能区的室内甲醛浓度进行监测和分析。结果表明:家具市场中包含木质家具的功能区甲醛浓度最高;服装批发市场中包含外贸针织功能区的甲醛浓度最高;综合商场中包含化妆品功能区的甲醛浓度最高;服装批发市场和家具市场整体的甲醛浓度已超过《商场(店)、书店卫生标准》(GB 9670—1996)规定的限值0.12mg/m3。3类公共场所甲醛点位超标率服从显著性水平p0.05的χ2双侧检验,具有统计学意义。长期暴露在服装批发市场和家具市场内的工作人员和顾客,可能存在健康风险,应对家具市场、服装批发市场的甲醛污染进行控制。     

谷胱甘肽对甲醛所致Hela细胞毒性的影响

为研究还原型谷胱甘肽(GSH)对甲醛所致Hela细胞毒性的影响,采用体外染毒方式,应用KC1-SDS法和MTT法分别检测GSH对甲醛引起Hela细胞DNA-蛋白质交联(DPC)和细胞活性的影响.结果表明,250μmol·L-1浓度下,DNA-蛋白质交联实验中甲醛染毒组所致的DPC显著高于对照组(p＜0.01),GSH+...     

MetalSafe便携式分析仪快速测定水中重金属

以镉和铅为例,采用MetalSafe便携式分析仪快速测定水中重金属,介绍了基于阳极溶出伏安法的测定原理及仪器操作步骤和技术参数.采用标准加入法,镉和铅的校准曲线线性良好,检出限分别为0.022μg/L和0.025μg/L,两个质量浓度水平的镉和铅标准溶液平行测定的RSD≤0.6%,相对误差＜5%.与火焰原子吸收光谱法作...