The current pandemic caused by COVID-19 has intensively triggered the development of high-performance air filters. Polypropylene (PP) is widely used as the raw material of meltblown nonwoven materials and is the core layer in air filters, such as masks. In this study, an electret PP meltblown nonwoven with antibacterial activity was developed, and nano boehmite (AlOOH) and nano-ZnO were employed as electret and antibacterial agents, respectively. AlOOH (0.5–2.0 wt%) and ZnO (1.0 wt%) were doped into the PP matrix using a twin-screw extruder, and the resulting masterbatches were applied as raw materials to produce nonwoven materials via a meltblown process. The as-prepared nonwoven samples were characterized by means of SEM, IR and DSC/TG. After corona charging, the filtration efficiency was determined by a filtration tester, charge decay was measured by an infrared electrostatic tester, and the antibacterial properties were evaluated (evaluation method: AATCC 100–2012). A dosage of AlOOH greater than 1.0 wt% endowed the nonwoven material with high filtration efficiency, and 1.0 wt% ZnO brought about antibacterial activity. Corona charging was an effective means to charge the nonwoven electret, and the charges were quicker to decay in air than in a sealed bag. The as-prepared meltblown nonwoven filter is a remarkably promising filter for air filtration. Electronic Supplementary Material (ESM) The online version of this article (doi: 10.1007/s12221-022-4786-8) contains supplementary material, which is available to authorized users.

Meltblown (MB) nonwovens as air filter materials have played an important role in protecting people from microbe infection in the COVID-19 pandemic. As the pandemic enters the third year in this current global event, it becomes more and more beneficial to develop more functional MB nonwovens with special surface selectivity as well as antibacterial activities. In this article, an antibacterial polypropylene MB nonwoven doped with nano silicon nitride (Si3N4), one of ceramic materials, was developed. With the introduction of Si3N4, both the average diameter of the fibers and the pore diameter and porosity of the nonwovens can be tailored. Moreover, the nonwovens having a single-side moisture transportation, which would be more comfortable in use for respirators or masks, was designed by imparting a hydrophobicity gradient through the single-side superhydrophobic finishing of reactive organic/inorganic silicon coprecipitation in situ. After a nano/micro structural SiO2 precipitation on one side of the fabric surfaces, the contact angles were up to 161.7° from 141.0° originally. The nonwovens were evaluated on antibacterial activity, the result of which indicated that they had a high antibacterial activity when the dosage of Si3N4 was 0.6 wt%. The bacteriostatic rate against E. coli and S. aureus was up to over 96%. Due to the nontoxicity and excellent antibacterial activity of Si3N4, this MB nonwovens are promising as a high-efficiency air filter material, particularly during the pandemic.

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The determination of trace metals in seawater is an important project of marine environmental monitoring. However, the presence of many alkali metal ions with high concentration, such as sodium ion, seriously interferes with the detection limit and accuracy of atomic absorption spectrometry (AAS, flame/graphite furnace integrated). The conventional chemical methods for the enrichment of trace metals are complex, and low boiling point organic solvents are used. In this paper, a kind of commercial cross-linked polystyrene resin microspheres was chloromethylated and aminated to introduce EDTA-type amino polycarboxylic groups and then loaded in a column as the absorption filler. A set of seawater pretreatment and enrichment devices was designed and assembled. The enriching process and conditions of trace Cu, Zn, Pb, and Cd in standard seawater were studied. 10 g of the modified resin could enrich the equivalent seawater and remove successfully the light metal ions. pH = 5∼9 and 0.2 mL/min of the flow rate were the suitable conditions for preconcentration. The enriched metal ions in the eluent were analyzed on the AAS. Compared with the conventional solvent method, the novel material and enrichment device have high preconcentration efficiency, strong anti-interference ability, and low cost and could be directly applied for routine seawater detection.