Respiratory disease caused by the presence of bacteria in the atmosphere seriously threatens human health. Air pollution as harmful suspended particles, like haze, is conducive to bacterial spread and growth; it must be prevented to avoid harming the respiratory tract. Herein, filtration membranes possessing superior antibacterial activity are considered as an effective means to protect humans from atmospheres contaminated with bacteria. The aim of this study is to prepare an environmentally friendly and biodegradable multifunctional biopolymer composite nanofibrous membrane, which can be used as a candidate material for air filtration applications. Since traditional air filtration materials do not degrade in the natural environment, we synthesized a nanofibrous membrane composed of gelatin (GT) and silk fibroin (SF), in which antibacterial agent can anchor via electrostatic spinning. Also, both GT and SF can break down in the natural environment, which avoids secondary pollution of the atmosphere. Preliminary experiments show that GS nanofibrous membranes are excellent carriers of antibacterial agent for antibacterial applications. Several characterizations and testing measurements indicate that resultant nanofibrous membranes are effective against Gram-positive and Gram-negative bacteria. Moreover, a water vapor transmission rate test shows the excellent filtration performance of the materials.

A silver (Ag)-loaded biostructured carbon/cadmium sulfide (CdS) lamellar composite photocatalyst was synthesized using a hydrothermal and photodeposition method. Camellia petals functioned both as a biological layered template and as a source of carbon. The prepared composite photocatalyst demonstrated good absorption under visible light and exhibited excellent photocatalytic degradation performance. The photocatalytic degradation efficiency of the obtained 457 composites substantially improved compared with pure CdS. The 5 wt.-% Ag-loaded C/CdS sample exhibited the highest photocatalytic activity, reaching 96.5 % after 180 min, which was 8.7 times that of pure CdS. Specifically, the biocarbon sheet enhanced the absorption of visible light. Furthermore, the high electrical conductivity of Ag can effectively transfer and separate photogenerated electrons and holes, thus enhancing both photocatalytic performance and stability.