A mini-review on building insulation materials from perspective of plastic pollution: Current issues and natural fibres as a possible solution.

As plastic pollution is eroding our ecological environment at an alarming rate around the world, tracking the origins is a necessity for putting forward effective measures to prevent it. The building industry, as an important sector consuming plastic products and producing plastic wastes, is increasing application of thermal insulations to improve energy efficiency. However, most insulation materials have negative impact on the environment. With the strategies to boost sustainability of buildings, natural fibres have occurred in the market as promising raw materials for thermal insulations. This mini-review aims to describe the extent building insulations contributed to plastic pollution, and a possible solution to plastic pollution from natural fibres and their current shortcomings. Hopefully, the mini-review could advance the current knowledge on contribution of building materials, especially thermal insulations to the ubiquitous plastic pollution, and the potential of natural fibres for replacing the plastic insulations, which could accordingly help future development of sustainable green insulations.

Preparation and Performance of Lignin-Based Multifunctional Superhydrophobic Coating.

Superhydrophobic coatings have drawn much attention in recent years for their widespread potential applications. However, there are challenges to find a simple and cost-effective approach to prepare superhydrophobic materials and coatings using natural polymer. Herein, we prepared a kraft lignin-based superhydrophobic powder via modifying kraft lignin through 1H, 1H, 2H, 2H-perfluorodecyl-triethoxysilane (PFDTES) substitution reaction, and constructed superhydrophobic coatings by direct spraying the suspended PFDTES-Lignin powder on different substrates, including glass, wood, metal and paper. The prepared lignin-based coatings have excellent repellency to water, with a water contact angle of 164.7°, as well as good friction resistance, acid resistance, alkali resistance, salt resistance properties and quite good self-cleaning performance. After 30 cycles of sand friction or being stayed in 2 mol/L HCl, 0.25 mol/L NaOH and 2 mol/L NaCl solution for 30 min, the coatings still retain super hydrophobic capability, with contact angles higher than 150°. The superhydrophobic performance of PFDTES-Lignin coatings is mainly attributed to the constructed high surface roughness and the low surface energy afforded by modified lignin. This lignin-based polymer coating is low-cost, scalable, and has huge potential application in different fields, providing a simple way for the value-added utilization of kraft lignin.

Cellulose-based colorimetric sensor with N, S sites for Ag+ detection.

A novel cellulose-based colorimetric sensor (DAC-Tu) with N, S sites for Ag+ was prepared. The DAC-Tu exhibited excellent selectivity and sensitivity for Ag+ with a naked eyes color change from white to black in mixed metal ions aqueous solutions. The naked-eye in-situ detection limit of DAC-Tu for Ag+ was 10-6 mol/L within 10 min. The cellulose matrix and the grafted functional groups (CS, NH2) of DAC-Tu all contributed to the low naked-eye in-situ detection limit. The mechanism of the visual recognition of DAC-Tu sensor for Ag+ was proposed, the N and S atoms of DAC-Tu preferentially coordination chelated with Ag+ to form NAg, SAg, and Ag2S, and enriched on the cellulose matrix, thus the DAC-Tu presented different color change in response to different concentrations of Ag+. The as-prepared DAC-Tu colorimetric sensor showed a great application prospect for in-situ naked eyes detection of Ag+.

Facile preparation of iron oxide doped Fe-MOFs-MW as robust peroxydisulfate catalyst for emerging pollutants degradation.

A novel catalyst (Fe-MOFs-MW) was facilely synthesized under microwave-assisted with NaOH as modulator for activating peroxydisulfate (PDS). The accelerated nucleation process was confirmed by Johnson-Mehl-Avrami (JMA) model. There were abundant reactive sites on prepared Fe-MOFs-MW while maintaining high Space-Time-Yield value up to 2300 kg/m3·d. Degradation performance of Fe-MOFs-MW as PDS catalyst on sulfamethoxazole (SMX) removal was evaluated. Results indicated that Fe-MOFs-MW with more Fe element anchored (10%) exhibited excellent catalytic capacity for PDS. Besides, the fantastic stability and reusability were confirmed through recycle experiment. After recycled for 4 times, the removal efficiency of SMX and TOC was 88% and 31.3% compared to 98% and 38% without recycling, respectively. An accurate prediction model on the degradation effect with water matrices coexisted was established by response surface methodology (RSM) method. Moreover, SO4·-, O2·- and ·OH were confirmed as the main reactive species through chemical quenching and EPR tests. The mechanism of Fe-MOFs-MW/PDS process mainly based on electron circulation theory was proposed. As the robust PDS catalyst, facile prepared Fe-MOFs-MW was promising in the treatment of emerging pollutants.

A kinetic model for oxidative degradation of bagasse pulp fiber by sodium periodate.

In this paper, some key parameters, such as the system pH, the periodate concentration, and the reaction temperature, on the influence of the bagasse fiber degradation were studied based on the oxygenant of periodate. And the feasible reaction mechanism was also discussed through the FTIR characterization for bagasse fiber before and after the oxidizing reaction. As the results shown, the crystallinity of bagasse fiber decreased with the oxidation level increasing. It was interesting that the aldehyde content of the reaction system rose gradually along with cellulose degradation. Based on this result, the selective oxidation kinetics was constructed by introducing of variable factor R (the ratio of aldehyde content to the degradation of cellulose fiber), and the results shown that there was a better correlation between the dynamic model and the experimental data, so the oxidation degree of bagasse fiber oxidized by periodate can be quantitative evaluated based on this model.