Cellulose nanofibrils (CNF) are steadily gaining attention since this material is a renewable alternative to artificial polymers. Moreover, waste products from cellulose-based industries (e.g. paper mills) or from agriculture can be used as raw material for CNF isolation. However, the up-scaling from the laboratory to the industry can only be achieved if the energy costs are low enough to compete against low-price petroleum derivatives. The objective of this work is to present an energy-related study of the direct fibrillation of cellulose-based materials using a grinding process. Two waste materials, namely wheat straw and recycled newspaper, have been investigated as starting materials, together with bleached wood pulp for comparison purposes. The mechanical properties and specific surface areas of the resulting fibrillated materials are then presented and systematically compared with each other. The properties of the bleached wood-pulp fibres exhibited the highest values that were reached already at low energy inputs. The different properties of CNF isolated out the waste materials could reach values close to their maxima for energy inputs as low as about 5 kWh/kg compared to the ca. 10 kWh/kg needed with high pressure homogenization.

This tutorial review reports on the different numeration methods for evaluating the efficiency of the photocatalytic action on microorganisms. Here we put forward the advantages and drawbacks of the standard methods such as the plate count, the fluorescence techniques and the Most Probable Number method for determining the biocidal photocatalytic activity and thus selecting efficient photocatalytic materials among complex systems. We highlight that bacterial spores are a representative and suitable tool for meeting the restrictive requirements resulting from the complex use of living matter instead of chemical targets.

TNT: Silicon microcantilevers modified with a three‐dimensional layer of vertical titanium dioxide nanotubes (see picture) can be used in micromechanical sensors with optical signal detection to detect low levels of explosives such as 2,4,6‐trinitrotoluene (TNT) in the gas phase, even in the presence of other volatile impurities such as n‐heptane and ethanol.

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