Removal of hydrophobic volatile organic compounds with sodium hypochlorite and surfactant in a co-current rotating packed bed.

A co-current flow rotating packed bed was applied to remove volatile organic compounds (VOCs) by sodium hypochlorite (NaClO) and surfactant (sodium dodecyl benzene sulfonate, SDBS) from air stream. Xylene was used as a model VOC herein. The effect of pH, concentration of NaClO and SDBS solution, liquid flow rate, gas flow rate and rotational speed on xylene removal efficiency and overall mass transfer coefficient (KGa) were discussed. Then, a correlation for KGa of the co-current rotating packed bed was proposed by fitting the experimental data of KGa and independent variables of liquid/gas ratio, rotational speed, pH, NaClO concentration and treatment time, which was in good agreement with the experimental data (the deviation≤±30%).

Determination of time- and size-dependent fine particle emission with varied oil heating in an experimental kitchen.

Particulate matter (PM) from cooking has caused seriously indoor air pollutant and aroused risk to human health. It is urged to get deep knowledge of their spatial-temporal distribution of source emission characteristics, especially ultrafine particles (UFP<100nm) and accumulation mode particles (AMP 100-665nm). Four commercial cooking oils are auto dipped water to simulate cooking fume under heating to 265°C to investigate PM emission and decay features between 0.03 and 10µm size dimension by electrical low pressure impactor (ELPI) without ventilation. Rapeseed and sunflower produced high PM2.5 around 6.1mg/m3, in comparison with those of soybean and corn (5.87 and 4.65mg/m3, respectively) at peak emission time between 340 and 460sec since heating oil, but with the same level of particle numbers 6-9×105/cm3. Mean values of PM1.0/PM2.5 and PM2.5/PM10 at peak emission time are around 0.51-0.66 and 0.23-0.29. After 15min naturally deposition, decay rates of PM1.0, PM2.5 and PM10 are 13.3%-29.8%, 20.1%-33.9% and 41.2%-54.7%, which manifest that PM1.0 is quite hard to decay than larger particles, PM2.5 and PM10. The majority of the particle emission locates at 43nm with the largest decay rate at 75%, and shifts to a larger size between 137 and 655nm after 15min decay. The decay rates of the particles are sensitive to the oil type.

[Particle Size Distribution and Diffusion for Simulated Cooking Fume].

Studying particle size distribution and dispersion characteristics of cooking oil fume can help to analyze the influence of the particles on indoor air quality and the health of the residents.Electrical low pressure impactor (ELPI) was employed to measure the number and mass concentration of the particles size range of 0.03-10 µm at two different locations in the kitchen space with smoke exhaust on and off,respectively.The cooking particles were mostly located at below 655 nm.The smoke exhaust with open condition could remarkably decrease the kitchen's cooking fume.The number concentration of particles decreased from 2.8×106 cm-3 to 2.3×105 cm-3,and PM2.5(aerodynamics diameter ≤2.5 µm particulate matter) mass concentrations decreased from 85.9 mg·m-3 to 6.2 mg·m-3.The sucking efficiency of smoke exhaust for PM10 was higher than PM2.5.The number concentration of particles could be declined by 65%,and the cooking fume of PM2.5 could be declined by 75% during the diffusion process detected at the area of 3 m far away from the area where cooking took place.The distribution of PM2.5 mass concentration field of oil fume was simulated by computational fluid dynamics.The temperature field distribution of oil fume was monitored by infrared camera,presenting sector diffusion with the temperature decreasing from 70℃ to room temperature.

Self-assembly of linear [Mn(II)2Mn(III)] units with end-on azido bridges: the construction of a ferromagnetic chain using ST = 7 high-spin trimers.

The controlled organization of high-spin complexes into 1D coordination polymers is a challenge in molecular magnetism. In this work, we report a ferromagnetic Mn trimer Mn3(HL)2(CH3OH)6(Br)4·Br·(CH3OH)2 1 (H2L = 2-[(9H-fluoren-9-yl)amino]propane-1,3-diol) with the ground spin state of ST = 7 that can be assembled into a one-dimensional coordination chain [Mn3(HL)2(CH3OH)2(Br)4(N3)(H2O)·CH3OH]∞ 2 using azido bridging ligands. Interestingly, the ferromagnetic nature of 1 is well retained in 2. However, due to the negligible magnetic anisotropy in 1, both 1 and 2 do not show slow-relaxation of magnetization, which indicates that during the process of molecular assembly not only the intratrimer magnetic interaction but also the magnetic anisotropy of the trimer can be reserved.