Application of activated carbon derived from bacterial cellulose for mesoporous HZSM-5 catalyst synthesis and performances of catalyst in bioethanol dehydration

Bacterial cellulose-derived activated carbon (BC-AC) was used as a hard template for mesoporous HZSM-5 zeolite synthesis. HZSM-5 zeolites were then applied as a catalyst for bioethanol dehydration. HZSM-5 zeolite catalyst obtained at the ratio of BC-AC to SiO2 of 0.4 (HZSM-5-0.4) exhibited very high catalytic performances and stability, in which the bioethanol conversion at 95.5-100%, with ethylene selectivity of 97.2-100% was obtained at the reaction temperature of 250-400 °C; whereas, the bioethanol conversion at 52.1%, with diethyl ether selectivity of 97.8% was obtained at 200 °C. The highly ordered mesoporous structure of HZSM-5-0.4 catalysts was found to promote mass transfer diffusion, resulting in the improved conversion and selectivity as well as the reduction of coke deposits. Consequently, BC-AC has an excellent potential to be used as a hard template for highly efficient and stable mesoporous HZSM-5 zeolite catalyst synthesis

Green composite sponge of natural rubber reinforced with cellulose filler using alginate as a dispersing agent

Composite sponges of natural rubber and cellulose fiber (NR-C) using sodium alginate (SA) as a dispersing agent were successfully fabricated by the Dunlop process. The aim of this work was to develop a green composite NR-C sponge with high mechanical properties and efficient water absorption capacity (WAC). The addition of SA could promote cellulose fiber dispersion in NR matrix and NR-cellulose interactions; accordingly, it resulted in highly macro-porous sponges with improved mechanical properties and higher hydrophilicity. NR-C sponge supplemented with cellulose at 45 parts per hundred rubbers (phr) and SA at 1 phr revealed significantly higher compressive stress and higher modulus of elasticity of about 5 times those of NR sponge. The maximum WAC at around 400 % was obtained from NR-C sponge supplemented with 30–45 phr cellulose and 1 phr SA. The initial water absorption rate and WAC of NR-C sponges were increased up to 5.6 and 1.8 times those of NR sponges, respectively. In addition, NR-C reinforced with high content of cellulose and SA could be sufficiently biodegraded in soil for about 21–27 % in120 days, which was considerably higher than that of NR sponges. According to their improved properties, NR-C composite sponges could be used an adsorbent or supporting material in many applications, including agriculture applications, such as a seed germination sponge or a hydroponic planting material and could also be further developed for biomedical applications as wound dressing

Synthesis of mesoporous MFI zeolite via bacterial cellulose-derived carbon templating for fast adsorption of formaldehyde

Mesoporous ZSM-5 (MFI) zeolite was synthesized by using bacterial cellulose-derived activated carbon (BC-AC500) with a high surface area as a hard template. Different ratios of BC-AC500 and zeolite precursor gel were prepared in a Teflon-lined autoclave and crystallized at 180 ºC for 48 h in a rotating oven. The physicochemical properties of the samples were characterized by x-ray diffraction (XRD), scanning/transmission electron microscopies (SEM/TEM), and N2 physisorption techniques. It was found that the mesoporous ZSM-5 zeolites have a specific surface area of 184-190 m2/g, a high mesopore volume of 0.120-0.956 ml/g and a wide pore size distribution ranging from 5 to 100 nm with a maximum at approximately 25.3 nm. The successfully made mesoporous ZSM-5 was tested as an adsorbent for formaldehyde adsorption in batch mode. The mesoporous ZSM-5 zeolite made from bacterial cellulose-derived activated carbon showed significantly faster adsorption kinetics than conventional ZSM-5 (0.0081 vs. 0.0007 g/mg min, respectively). The prepared material has an adsorption capacity of 98 mg/g and is highly reusable. The reported mesoporous ZSM-5 zeolites can be deployed for the rapid removal of toxic organics from wastewater when urgently needed, e.g., under breakthrough conditions

Ionic Silver and Electrical Treatment for Susceptibility and Disinfection of Escherichia coli Biofilm-Contaminated Titanium Surface

In this work, surface disinfection and biofilm susceptibility were investigated by applying ionic silver of 0.4–1.6 µg/mL and cathodic voltage-controlled electrical treatment of 1.8 V and a current of 30 mA to Escherichia coli (E. coli) ATCC 25922 biofilm-contaminated titanium substrates. Herein, it is evident that the treatment exhibited the potential use to enhance the susceptibility of bacterial biofilms for surface disinfection. In vitro studies have demonstrated that the ionic silver treatment of 60 min significantly increased the logarithmic reduction (LR) of bacterial populations on disinfectant-treated substrates and the electrical treatment enhanced the silver susceptibility of E. coli biofilms. The LR values after the ionic silver treatments and the electric-enhanced silver treatments were in the ranges of 1.94–2.25 and 2.10–2.73, respectively. The treatment was also associated with morphological changes in silver-treated E. coli cells and biofilm-contaminated titanium surfaces. Nevertheless, the treatments showed no cytotoxic effects on the L929 mouse skin fibroblast cell line and only a slight decrease in pH was observed during the electrical polarization of titanium substrate