Regulating the aggregation of anionic nanoparticles for size-tunable nanochannels

Mechanically robust carboxymethyl cellulose/graphene oxide composite cross-linked by polyetherimide for fruits packaging and preservation system

Modulating the interactions between biopolymer matrix and nanofillers highly determined the mechanical performances of composite packaging materials. Herein, we innovatively proposed a sort of eco-friendly and mechanically robust carboxymethyl cellulose/graphene oxide/tannic acid/polyetherimide (CMC/GO/TA/PEI, CGTP) composite by employing PEI as cross-linker and TA as proton donor. The amidation reaction between -NH2 and -COOH chemically connected the CMC/GO, CMC/CMC and GO/GO and the physical interaction (e.g. hydrogen bonds and molecular entanglements) was beneficial to form dense structures. The chemical/physical bonds among polymers and nanofillers contributed to dissipate the external energy. The toughness was effectively reinforced from 1.68 MJ/m3 for CGTP0 to 4.63 MJ/m3 for CGTP1.0. Furthermore, the CGTP1.0 composite film also delivered improved gas (moisture and oxygen) barriers, UV protection and antimicrobial features. Originating from these merits, the shelf life of fresh fruits (e.g. strawberries, blueberries and cherry tomatoes) was prolonged at least 5 days under ambient conditions when the packaging box was covered by the fabricated CGTP1.0 film. Our findings not only provided a facial strategy to reinforce the interactions between biopolymer matrix and nanofillers, but also boosted the development of eco-friendly packaging materials with robust structures in the area of food packaging.

Low-Pressure Membrane for Water Treatment Applications

Three ultrafiltration membranes were prepared using phase separation techniques. The membranes were characterized by scan electron microscope, porosity, pore size distribution measurement, and mechanical properties. The membrane performance was carried out using synthetic solutions from humic acid and tap water to express the contaminated drinking water. The polyvinylidene difluoride (M2) has the highest tensile strength 33.2 MPa with elongation of 52.3%, while polyacrylonitrile (M3) has the lowest mechanical properties, tensile strength 16.4 MPa with elongation of 42.7%. Polyethersulfone membrane (M1) provides the highest removal of humic acid, which was 99.5, 98.8, and 98.2% using feed concentrations 0.1, 0.3, and 0.5 g/l, respectively, while M3 provides the highest permeate flux which was 250, 234.4, and 201.4 l/m2 h using feed concentrations 0.1, 0.3, and 0.5 g/l, respectively. Analysis of water samples indicates that the prepared membranes can be used to treat the contaminated drinking water which produced the high quality of drinking water after treatment.