汽车涂料废物挥发性有机物气相释放特征

Gas Phase Emission Characteristics of Volatile Organic Compounds(VOCs) from Automotive Paint Waste

汽车涂料废物作为有机污染物类典型固废,在全过程管理各环节都存在挥发性有机物(VOCs)释放的环境风险.本文选取同一涂装工段下不同漆雾捕集技术产生的漆渣与干式石灰石粉,采用环境测试舱-气相色谱/质谱法,研究涂料废物中VOCs的气相释放特征.结果表明:①相同工艺下漆渣与干式石灰石粉释放的VOCs种类相似,但漆渣中各组分释放速率和累计释放量远高于干式石灰石粉.②漆渣与干式石灰石粉均在1 h左右达到VOCs的释放速率峰值,在检出的7种主要VOCs中,最高者同为正丁醇,分别为245.37、22.67 mg/(m^(2)·h);最低者同为邻-甲乙苯,分别为11.49、2.50 mg/(m^(2)·h).③经过130 h(漆渣)和24 h(干式石灰石粉)的长期散发试验,试验结束时漆渣累计释放量最大的是正丁醇和1,2,4-三甲基苯,分别为4.76×10^(3)、2.86×10^(3) mg/m^(2);干式石灰石粉累计释放量最大的是1,2,4-三甲基苯和正丁醇,分别为77.26、63.75 mg/m^(2);二者累计释放最低的同为邻-甲乙苯,分别为467.91、11.29 mg/m^(2).④两种样品中VOC释放周期均分为释放初始期(峰值期)、过渡期和缓慢衰减期(准稳态期)3个阶段.除漆渣中浓度最高的正丁醇外,其余各组分均具有一致的过渡期(1~9 h)和缓慢衰减期(9 h之后),但干式石灰石粉达到稳态的时间远低于漆渣.研究显示,干式漆雾捕集技术所产生的干式石灰石粉相较传统湿式工艺产生的漆渣,二者所释放的VOCs组分种类相似,存在相同的释放阶段,但释放周期和累计释放量大幅降低,在VOCs减排上具有显著优势.

Automobile paint waste is a typical organic pollutant solid waste,and there are environmental risk of volatile organic compounds(VOCs)emissions in all aspects of the whole process of management.The paint sludge and dry limestone powder produced by different paint mist capture technologies in the same painting section were selected,and the gas phase release characteristics of VOCs in the paint waste were studied by using the environmental test chamber-GC/MS method.The results show that:(1)The VOCs released by paint sludge and dry limestone powder under the same process were similar,but the release rate and cumulative release of each component in paint sludge were much higher than those of dry limestone powder.(2)The release rates of all detected seven main VOCs reached the peak value at about 1 hour,of which the 1-butanol was the highest,the paint sludge and dry limestone powder were 245.37 and 22.67mg/(m^(2)·h),respectively,and the lowest was the same as the o-methyl ethyl benzene,respectively 11.49 and 2.50 mg/(m^(2)·h).(3)At the end of the test,after 130 h(paint sludge)and 24 h(dry limestone powder)long-term emission test,the largest cumulative release of paint residue was 1-butanol and 1,2,4-trimethylbenzene,which were 4.76×10^(3) and 2.86×10^(3) mg/m^(2),respectively.The largest cumulative release of dry limestone powder was 1,2,4-trimethylbenzene and 1-butanol,which were 77.26 and 63.75 mg/m^(2),respectively.The lowest cumulative release of the two was o-methyl ethylbenzene,which were 467.91 and 11.29 mg/m^(2) respectively.(4)The VOCs release cycle of the two samples was divided into three phases:the initial release period,the transition period and the slow decay period.Except for the highest concentration of n-butanol in the paint sludge,the other components had a consistent transition period(1-9 h)and a slow decay period(after 9 h),but the time for the dry limestone powder to reach a steady state was much shorter than that of the paint sludge.The research shows that compared with the paint sludge produced by the traditional wet process,the dry limestone powder produced by the dry paint mist capture technology releases similar VOCs components and has the same release stage,but the release cycle and cumulative release are greatly reduced,which has significant advantages in VOCs emission reduction.