2022, Vol. 7, No. 1
Consumers prefer foods that are healthier with high quality and safety. Food packaging are demanded to effectively extend the shelf-life, preserve the nutrients and decrease the microbial contamination during the transport and storage of food. With the increasing concern on the environmental impacts caused by food packaging wastes, sustainable and green packaging are highly demanded to minimize the harmful effects of food packaging waste on the environment. Bio-based materials are derived from sustainable and renewable biomass, instead of finite petrochemicals. The applications of bio-based materials for food packaging are highlighted in this review. The emphasis is placed on the categories of related biobased materials, their characteristics and advantages for food packaging, as well as the strategies used to improve their performances. Though a lot of trials have been done on biobased materials for food packaging, further attempts to improve their performances, understand the functioning mechanisms and develop greener methods for the production, processing and destiny of these bio-based materials are still highly needed for the future research.
There are significant incentives/pressures on decreasing the use of plastics and their related prod-ucts in the packaging industry, correspondingly, strong demands are emerging for clean, renew-able, recyclable/biodegradable packaging products. In this context, molded fiber/pulp products have attracted increasing attention, due to their green/sustainable advantages, simply because the raw materials used are plant-based and/or recycled fibers. Many companies have switched their packing practices from plastics to more environmentally friendly products, such as molded fiber products, which already have had and will continue to have obvious effect on packaging industries. This paper initially provides an overview on the general concept of molded pulp prod-ucts, and further summarizes the different types of molded fiber products in terms of natural fiber sources, manufacturing processes, current and emerging applications as well as the environmental sustainability of molded products.
Fungal construction materials—substrates colonised by mycelium—are getting increased recog-nition as viable ecologically friendly alternatives to conventional building materials. A function-ality of the constructions made from fungal materials would be enriched if blocks with living mycelium, known for their ability to respond to chemical, optical and tactile stimuli, were in-serted. We investigated how large blocks of substrates colonised with mycelium of Ganoderma resinaceum responded to stimulation with heavy weights. We analysed details of the electrical re-sponses to the stimulation with weights and show that ON and OFF stimuli can be discriminated by the living mycelium composites and that a habituation to the stimulation occurs. Novelty of the results cast in the reporting on changes in electrical spiking activity of mycelium bound composites in response to a heavy loads.
Brønsted acid site (S/Cl)-functional carbon materials were prepared by ball-milling (bm) L-cysteine and ammonium chloride to form chemical complex solids, by post-heat treatment (Q) of the solids at 500 ℃ under a nitrogen gas atmosphere to stabilize and fortify amino and functional group solid structures and by post-oxidative treatment with H2O2 to add Brønsted acidity. The as-prepared carbon materials (S/Cl@bmxQy; x, y in hours) contained Brønsted acid sites (sul-fonates, chlorides), oxygen-containing groups (-COOH, -OH) and amino functional groups. The S/Cl@bmxQy materials were applied as catalysts to promote conversion of fructose in ethanol solvent to 5-hydroxymethylfurfural (5-HMF) and 5-ethoxymethylfurfural (5-EMF). Among the carbon materials, S/Cl@bm3Q1 gave 5-EMF and 5-HMF yields of 67.0% and 22.8%, respectively, in pure ethanol at 140 ℃ for 24 h reaction time, while a reaction time of 18 h gave total 5-EMF and 5-HMF yields of 96.4%. Dimethyl sulfoxide (DMSO) was applied as additive to the ethanol-fructose- S/Cl@bm3Q1 reaction system which showed that 5-HMF product selectivity could be controlled with DMSO concentration. The protocol developed allows simple preparation of func-tional carbon materials that have high catalytic activity and are effective for conversion of fructose to 5-HMF and 5-EMF in ethanol.
Palm fatty acid distillate (PFAD), a by-product of refining process of crude palm oil can be used as a potential feedstock for biodiesel production. However, the application of palm oil-based biodiesel is often hinder by its poor cold flow properties (CFP). Biodiesel fuel with poor CFP may crystallize and result in clogging of fuel lines, filters and injectors that cause engine operability problems. For that, a vacuum distillation method was designed and its feasibility and efficiency in improving the CFP was examined. A total of 13.60wt% of total saturated fatty acid methyl esters were successfully removed from the PFAD biodiesel, resulting in the improvement of the cloud point (CP), cold filter plugging point (CFPP) and pour point (PP) of PFAD biodiesel from 20 ℃, 19 ℃, and 15 ℃ to 13 ℃, 11 ℃, and 9 ℃, respectively. It is remarkable that the improved CFPP satisfied the requirements for grade C summer biodiesel for temperate climates in EN 14212 standard. Additionally, Sarin (UFAME) empirical correlation was evaluated and it was found to have a good prediction of CFP for PFAD biodiesel, with lower than 2 ℃ deviation.
The aerial parts of Haplophyllum tuberculatum (H. tuberculatum) have traditionally been used by local communities to treat fever, gastrointestinal disorders, worms, malaria and fractures, however, the responsible ingredients of the selected medicinal plant have not been identified. In the present study, antibacterial and antioxidant ingredients were isolated and characterized from the plant parts of locally grown H. tuberculatum, and their biological activity was evaluated. The powder aerial parts were extracted with methanol and the extract was successively fractionated with different polarities of solvents. All polarities of extracts (hexane, chloroform, ethyl acetate, butanol, methanol and water) were used to determine their antibacterial and antioxidant activity by established in-vitro method. The disk diffusion and free radical scavenging 2, 2-diphenyl-1-picrylhydrazyl (DPPH) methods were used to evaluate antibacterial and antioxidant activities of the prepared extracts and pure isolated compounds at different concentrations against three strains of Gram-positive and three Gram-negative bacteria. The antibacterial activity results showed that all prepared fractions and isolated pure compounds of the plant species gave significant activity against all Gram (+ and -) bacterial strains with the range of inhibition 0-20 mm. The antioxidant activity of the prepared extracts at all concentrations also showed substantial activity. Based on the highest activity, ethyl acetate and chloroform extracts were selected for the separation and isolation of antioxidant and antibacterial compounds by thin layer chromatography (TLC), column chromatography (CC), and preparative thin layer chromatography (PTLIC). The structure of the isolated antioxidant and antibacterial compounds from the ethyl acetate and chloroform extracts were determined on the basis of nuclear magnetic resonance (NMR) and mass spectra. The isolated pure compounds and active extracts could be used as a medicine for various infectious related diseases.
The application of porous carbon microspheres derived from pure biomass in supercapacitors is restricted due to their limited reactive groups. MXene owns a combination of redox Faradic surface with good metallic conductivity and hydrophilicity, which assists to obtain high pseudocapacitance and energy density. Herein, Ti3C2Tx MXene was introduced to chitosan-based porous carbon microsphere (CPCM) to fabricated sandwich-like structure (CPCM/MXene) through electrostatic interaction. The Ti3C2Tx protected the spherical structure of CPCM. Meanwhile, CPCM hindered the reaggregation of Ti3C2Tx by inserting in the Ti3C2Tx layers, promoting the electrolyte migration kinetics. The synergistic effect endowed CPCM/MXene high specific capacitance of 362 F/g at current density of 0.5 A/g and acceptable cycling stability with 93.87% capacitance retention at a high current density of 10 A/g after 10, 000 cycles. Furthermore, CPCM/MXene displayed a high energy density of 27.8 W/(h·kg) at 500.0 W/kg of power density. These satisfactory performances prove that combining Ti3C2Tx MXene nanosheets with porous carbon microspheres is a considering method to construct a new generation electrode material of supercapacitor.
Environmental problems have attracted much attention in recent years, especially for papermak-ing wastewater discharge. To reduce the loss of effluence discharge violation, quality-related multivariate statistical methods have been successfully applied to achieve a robust wastewater treatment system. In this work, a new dynamic multiblock partial least squares (DMBPLS) is proposed to extract the time-varying information in a large-scale papermaking wastewater treatment process. By introducing augmented matrices to input and output data, the proposed method not only handles the dynamic characteristic of data and reduces the time delay of fault detection, but enhances the interpretability of model. In addition, the DMBPLS provides a capability of fault location, which has certain guiding significance for fault recovery. In comparison with other mod-els, the DMBPLS has a superior fault detection result. Specifically, the maximum fault detection rate of the DMBPLS is improved by 35.93% and 12.5% for bias and drifting faults, respectively, in comparison with partial least squares (PLS).