环境测试舱自吸附甲醛重释放规律与影响因素研究

广泛用于板材污染物释放量测试、空气净化产品净化效果测试等实验中的环境测试舱,往往由于其内壁黏附性杂质而对目标测试物产生不可忽视的自吸附作用,自吸附污染物将作为二次释放源出现重释放,研究目标测试物的自吸附消耗量及重释放规律,探索有效控制措施,有利于对环境测试舱实验应用及室内污染控制提出指导性实际意义。分别选取0.2%甲醛溶液、大芯板作为同一自制玻璃环境测试舱2期实验(I期、Ⅱ期)的不同甲醛释放源,通过近90 d追踪测试,经不同释放源、不同控制条件下舱内壁自吸附甲醛的多次重释放实验,结合非线性拟合分析方法,总结出舱内壁自吸附甲醛重释放甲醛浓度变化符合一阶递增指数函数:y=A1×exp(-x/t1)+y0,(A1<0、t1>0)。曲线参数y0值可用于评价实验条件下测试舱内自吸附甲醛残余量;y0值与环境舱舱体材质、环境温湿度、舱外甲醛浓度及空气交换手段有关,而与释放源及其释放平衡浓度高低无明显关系。大开舱门短时间抽气式空气交换对舱内自吸附甲醛残余有适度清除效果,使y0值降低,同时有利于再次平衡状态的快速建立;而长时间的无动力空气交换,或者自来水洗及去离子水洗等处理手段对舱内壁自吸附甲醛残余无明显清除作用。

Research of re-releasing rules and influencing factors of formaldehyde self-adsorbed on surface of environmental test chamber

Environmental test chamber is widely used to determinate the pollutant emission value of wood-based panels and testing the purificatory effect of indoor environment decontamination product.But the particles adhered to the wall of the test chamber also adsorbe formaldehyde from the formaldehyde emission source and form re-releaseing source of formaldehyde and affect the subsequent testing.So it is necessary to investigate the re-releasing rules and its influencing factors in order to improve the subsequent testing and proposed guidance opinion on the control of indoor pollution.In this project,0.2% formaldehyde solution and the wood-based panels was selected as formaldehyde emission source in the glassing test chamber for the two group experiments respectively.Trough 90 days experiment under the condition of different formaldehyde emission source and different controlling methods,a lot of experimental data were obtained.The experimental data were processed with integrate nonlinear fitting,and it was found that the re-releasing value of formaldehyde concentration of self-adsorbed formaldehyde in the chamber was changed accord with a first order increment exponential function: y=A1×exp(-x/t1)+y0,(A1<0、t1>0).The y0 value can be used to evaluate the residue value of formaldehyde in the chamber.It also can be found that the y0 value is connection with the material of the chamber,the temperature,the relative humidity,and the means of the air ventilation.But it is independent to the release source of formaldehyde and the releasing steady-state concentration of formaldehyde.Opening the chamber door and extracting air ventilation in a short time will benefit reduction of the residual formaldehyde in the chamber.But it is no visible effects to reduction of the residual formaldehyde in the chamber with unpowered air ventilation,furthermore it also can be found that is useless to reducte the residual formaldehyde washed with deionized water.