Phytoremediation of Formaldehyde in Indoor Environment With Common House Plants and Pseudomonas Chlororaphis

Low light survivor house plants were assessed for their formaldehyde removal capacity from indoor environment. Low ventilation leading to poor air circulation in indoor environment has become a matter of grave concern as it leads to health issues. Phytoremediation technology is being studied in such situations. The capacity of plants in absorbing indoor pollutants can be enhanced through use of bacteria helping phytoremediation process. The gaseous formaldehyde of about 5 ppm was released into the static chamber of volume 1 m3 . Selected test plants were Aglaonema commutatum, Chlorophytum comosum, Sansevieria trifasciata and Epipremnum aureum. Medium in which plants were growing was inoculated with Pseudomonas chlororaphis, which helps the process of phytoremediation. Activated charcoal was also added in the medium, to increase the absorptive surface. The exposure given was for 24 hours. Experiment was replicated for three times. Air quality in the chamber was monitored on advanced Formaldehyde meter, at the start of the experiment and after 24 hours. Leaves of the plants were analysed by DNPH on LCMS method for quantification of Formaldehyde. Quantification of Formaldehyde from leaves ranged between 0.03–4.7 ppm. Formaldehyde meter showed reduction in formaldehyde quantity ranges from 1.999 to 0 ppm in 24 hours. This clearly indicates that selected plants have enhanced limited capacity of formaldehyde absorption in synergy with Pseudomonas chlororaphis.

Enhanced formaldehyde-removal over modified cryptomelane catalysts

M-OMS-2 materials (M = K+, Cu2+, Co2+) were prepared by an uncomplicated reflux method, and the cryptomelane crystalline structure was confirmed by X-ray diffraction patterns. Element analysis recorded ~56 - ~59 wt.% of Mn in the three synthesized samples and ~2.8 wt.% loadings of dopants over Co-OMS-2 and Cu-OMS-2 materials. A titration method valued the average oxidation states of manganese at 3.60, 3.71 and 3.77 for K-OMS-2, Co-OMS-2 and Cu-OMS-2, respectively. In comparison with K-OMS-2, Co and Cu dopants depicted a significant enhancement catalytic activity in removal of formaldehyde at low (5%) and high (65 %) relative humidity (RH). Cu-OMS-2 showed the highest catalyst performance with ~90 % of formaldehyde conversion at 150 °C, 65% RH, whereas only ~40 % (for Co-OMS-2) and ~26 % (for K-OMS-2) of that were observed. The finding results promised a potential Cu-OMS-2 material for designed low-costly catalyst in formaldehyde removal at a wide range of RH.

Preliminary experimental research of metal-organic frameworks (MOFs) for formaldehyde dynamic adsorption

Formaldehyde is a common emission from furniture and indoor decorations. Although the concentration of formaldehyde gas is not too high in the indoor environment, it is highly toxic and carcinogenic. The formaldehyde removal potential of a novel type of green and safe nano-porous materials, Metal-Organic Frameworks (MOFs), with a high surface-to-volume ratio, strong adsorption capacity, and low regeneration temperature was investigated. To date, researchers are mainly focusing on formaldehyde selectivity and detection using MOFs in low moisture circumstances. This study carried out a series of experiments to compare breakthrough curves of formaldehyde dynamic adsorption on MIL-100(Fe), MIL-160(Al), and aluminum fumarate with activated carbon. In experiments, the formaldehyde was evaporated from diluted formalin solution, dried to 30±5 % RH, and driven through different adsorbents by nitrogen. The results indicated that MOFs showed great potential for indoor air formaldehyde removal.

Simulation study on effects of purifier positions on formaldehyde removal under the condition of vehicle air supply

In order to further improve the interior air quality and comfort of the vehicle, CFD method is used to simulate the different airflow distribution caused by car-mounted air purifiers at different positions. Combined with the change of formaldehyde concentration field in car, the influence of car-mounted air purifiers on the formaldehyde dilution and removal under the condition of air conditioning air supply is analyzed. The simulation results are verified by actual measurement, and the trend of the simulation results is basically consistent with the measured results. When the car air purifier placed in the middle of the car roof, it can effectively dilute and purify the formaldehyde gas in the car, and reduce the concentration of formaldehyde in the breathing area of the driver and passengers. The adsorption and degradation of formaldehyde by the purifier, together with the dilution of formaldehyde by air supply, can improve the air quality in cars more effectively than using only one of the air purification methods.

Improving Formaldehyde Removal from Water and Wastewater by Fenton, Photo-Fenton and Ozonation/Fenton Processes through Optimization and Modeling

This study aimed to assess, optimize and model the efficiencies of Fenton, photo-Fenton and ozonation/Fenton processes in formaldehyde elimination from water and wastewater using the response surface methodology (RSM) and artificial neural network (ANN). A sensitivity analysis was used to determine the importance of the independent variables. The influences of different variables, including H2O2 concentration, initial formaldehyde concentration, Fe dosage, pH, contact time, UV and ozonation, on formaldehyde removal efficiency were studied. The optimized Fenton process demonstrated 75% formaldehyde removal from water. The best performance with 80% formaldehyde removal from wastewater was achieved using the combined ozonation/Fenton process. The developed ANN model demonstrated better adequacy and goodness of fit with a R2 of 0.9454 than the RSM model with a R2 of 0. 9186. The sensitivity analysis showed pH as the most important factor (31%) affecting the Fenton process, followed by the H2O2 concentration (23%), Fe dosage (21%), contact time (14%) and formaldehyde concentration (12%). The findings demonstrated that these treatment processes and models are important tools for formaldehyde elimination from wastewater.