No abstract

Gaseous formaldehyde emission from synthetic rubbers was simulated using a 60-L environmental chamber to explore the effect of different rubbers on formaldehyde emission. The formaldehyde emission factor (EF) of synthetic rubbers was more likely to exceed the limit for mixed type, which was mainly attributed to the quality of the adhesives in raw materials. Furthermore, the emission characteristics of mixed-type rubbers in small chambers were obtained. EF rapidly increased, especially during the inception stage, and then its rate of increase slowed, reaching a peak at approximately 4-5 h. The relative standard deviations of EF were within 5% when the measurement was extended to 13 h. This method can be used to monitor volatile hazardous substances emanating from synthetic rubbers, providing a theoretical basis for corresponding supervision. In addition, to degrade the background values in chambers, the photo-induced reactions were catalyzed with S-doped TiO2 under visible light, as this helped to shorten the pre-treatment time of the air in the chamber.

Carbon disulfide (CS2) emitted from rubber surfaces was determined by TD-GC-MS. Simulated with 60 L environmental chambers, the emission characteristics of CS2 from rubber surfaces were investigated. The quantitative approach was confirmed using a dynamic recovery experiment. The emission factors of CS2 presented a rapid increase especially in the inception phase, and an equilibrium status was obtained while the relative standard deviations were within 5% after 6 h. This method was quite appropriate for the emission characteristic research of sulfide, which provided a theoretical basis for the corresponding environmental supervision of rubber surfaces.

In this study, γ-Al2O3 was synthesized using a hydrothermal method and its morphology and chemical composition was characterized by transmission electron microscopy (TEM), energy dispersive X-ray (EDX) and X-ray diffractometer (XRD). The TEM images, EDX and XRD spectrum highlight good crystallization and multi-slice feathery microstructure, involving relatively pure crystal sintering. The Pb(II) concentration analysed by inductively coupled plasma mass spectrometry (ICP-MS) after centrifuging is linked to the γ-Al2O3 adsorption, and a removal method for Pb(II) from water passing through kitchen faucets is proposed. The Pb(II) value below 0.06 mg g−1 relative to the γ-Al2O3 value reveals 94% adsorption. Further assessment of the alumina separation effect for faucets shows Pb(II) precipitation from the downstream of the valve spool is below 0.16 μg L−1. About 0.12 g adsorbent is mixed with 1.0 L tap water to produce a suspension for effective soaking. The proposed method produced satisfactory results, providing a theoretical basis for authorities to exploit on heavy metal removal from kitchen faucets.