Calcium hydroxide recycled from waste eggshell resources for the effective recovery of fluoride from wastewater.

In the hunt of waste recovery pathways, eggshells emerged as a potential adsorbent for fluoride because they contain plenty of calcium. However, as the main component, calcite has weak interaction with fluoride. In this study, calcium hydroxide was derived from waste eggshells successfully by an aging treatment with moisture for fluoride recovery from water. The X-ray diffraction (XRD) and infrared spectroscopy (FT-IR) analyses indicate that CaO in calcined egg shells (AEG900) is completely converted to calcium hydroxide. The adsorption experiments showed that the adsorption capacity of AEG900 for fluoride was improved by nearly 29.21% compared with the calcined eggshells without the aging treatment. In the batch experiment, the temperature effect is the most significant for the adsorption process, and nearly a half increment of removal rate is achieved by increasing the temperature by 30 °C. Further research revealed that the adsorption process fitted well with the pseudo-second order model and the Langmuir-Freundlich isotherm model, with a maximum adsorption capacity of 370.15 mg g-1. Moreover, precipitation was regarded as the main step for fluoride removal mechanism based on the calculated results of the surface complexation model. X-ray photoelectron spectroscopy (XPS) results showed that the stable fluorite formed in situ of AEG900 avoids calcium loss in water. Finally, AEG900 was applied in fluoride removal with real-life groundwater and industrial wastewater, and the results showed that the final fluoride concentration could meet the WHO requirement and industrial wastewater discharge standard.

Evaluation on antiosteoporosis of collagen peptides prepared by immobilized protease with eggshell membrane.

Collagen peptides are a potential treatment for osteoporosis due to their antiosteoporosis activity. In this study, we prepared immobilized protease with eggshell membrane as carrier, and then hydrolyzed collagen to obtain collagen peptide. The antiosteoporosis of collagen peptides was confirmed by hBMSC osteogenic differentiation and bone mineralization improvement results. Surprisingly, antiosteoporosis of collagen peptides was related to the molecular weight of collagen peptides. This was derived from the osteoblast marker gene expressions, and mineral elements in P1 treatment were higher than those in P3 treatment. Consequently, these results confirmed that antiosteoporosis of low molecular weight collagen peptides is higher than that of higher molecular weight collagen peptides. Furthermore, the antiosteoporosis activity of P1 was due to its peptide sequences with known antiosteoporosis activity in P1. PRACTICAL APPLICATION: Using eggshell membrane as carrier to prepare immobilized protease was meaningful for solving the problem of resource waste. In addition, the results showed that collagen peptides possessed antiosteoporosis, and the effect of low molecular weight collagen peptides was better. This study provides a theoretical basis for developing high antiosteoporosis collagen peptides able to treat osteoporosis.

The integrated production of ultrathing-C3N4and membrane assisted by edible syrup for the sustained photocatalytic treatment of Cr(VI) and tetracycline.

The exfoliation of bulk raw graphitic carbon nitride (g-C3N4) by edible glucose syrup to produce ultrathing-C3N4nanosheets in concentrations of up to 0.2 mg ml-1was achieved. Detailed characterization through TEM, AFM, FT-IR, XRD, Raman and TGA confirmed the formation of ultrathin structure and improved properties. Compared to rawg-C3N4, the prepared thing-C3N4layers exhibited a 18-fold enhancement in Cr(VI) reduction and a 3-fold enhancement in tetracycline hydrochloride degradation, which is ascribed to their larger specific surface area and more exposed active sites. The layeredg-C3N4membrane was constructed via direct vacuum filtration. The layer-stackedg-C3N4nanosheet membrane exhibited an excellent and sustained photocatalytic performance as the prepared thing-C3N4layers could maintain a layered lamella after stacking in filtration process. The recyclable synthesis of ultrathing-C3N4layers and layer-stackedg-C3N4membrane by our method provides a sustainable strategy to pollution treatment by 2D materials.

Preparation of an Amidated Graphene Oxide/Sulfonated Poly Ether Ether Ketone (AGO/SPEEK) Modified Atmosphere Packaging for the Storage of Cherry Tomatoes.

The shelf life of cherry tomatoes is short so that new and efficient preservation techniques or procedures are required to reduce postharvest losses. This study focused on the development of a sulfonated poly ether ether ketone (SPEEK) film incorporated with amidated graphene oxide (AGO), for the storage of cherry tomatoes in modified atmosphere packaging. The mechanical properties, gas permeability, and moisture permeability were subsequently tested. The evolution of attributes related to shelf life, such as gas composition, physicochemical properties, and sensory properties were also monitored during storage trials. AGO, as an inorganic filler, increases the thermal stability and mechanical properties of SPEEK-based films, while it reduces the water absorption, swelling rate, and moisture permeability. Importantly, all the AGO/SPEEK films exhibited enhanced gas permeability and selective permeability of CO2/O2 relative to the SPEEK film. Moreover, 0.9% (w/w) AGO/SPEEK film showed an enhanced permeability coefficient of CO2, corresponding to an increase of 50.7%. It could further improve the selective coefficient of CO2/O2 to 67.1%. The results of preservation at 8 °C revealed that: 0.9% (w/w) AGO/SPEEK film was significantly effective at maintaining the quality and extending the shelf life of cherry tomatoes from 15 to 30 days, thereby suggesting the potential for applying AGO-incorporated SPEEK films for food packaging materials.

Nanocomposite packaging regulates extracellular ATP and programed cell death in edible mushroom (Flammulina velutipes).

Our previous study indicated that nanocomposite packaging material (Nano-PM) containing nano-Ag, nano-TiO2, nano-SiO2 and nanoattapulgite alleviated postharvest senescence of Flammulina velutipes by regulating respiration and energy metabolism. In this study, extracellular ATP (eATP) and programmed cell death (PCD) were employed as critical factors to further investigate the senescence mechanism of postharvest F. velutipes. Results demonstrated that Nano-PM delayed apyrase activity decrease and stimulated critical oxidative phosphorylation-related gene expression to inhibit eATP content increase, which is a crucial signaling molecule related to delaying senescence. The regulation of eATP resulted in alleviating PCD including chromosomal concentration, DNA fragmentation, Ca2+ influx, high caspase-1 activity and cytochrome c content and leading to high cell viability. Overall, Nano-PM alleviated PCD and postharvest senescence of F. velutipes by regulating extracellular ATP.

Ultrahigh-Pressure Liquid Chromatography-Quadrupole-Time-of-Flight Mass Spectrometry-Based Metabolomics Reveal the Mechanism of Methyl Jasmonate in Delaying the Deterioration of Agaricus bisporus.

Conquering rapid postripeness and deterioration of Agaricus bisporus is quite challenging. We previously observed that methyl jasmonate (MeJA) pretreatment postponed the deterioration of A. bisporus, but the mechanism is unknown. Here, a nontargeted metabolomics analysis by ultrahigh-pressure liquid chromatography-quadrupole-time-of-flight tandem mass spectrometry (UHPLC-QTOF-MS/MS) revealed that MeJA increased the synthesis of malate by inhibiting the decomposition of fumarate and cis-aconitate. MeJA maintained energy supply by enhancing ATP content and energy charge level and improving hexokinase and glucose-6-phosphate dehydrogenase activities as well. These results promoted ATP supply by maintaining glycolysis, the TCA cycle, and the pentose phosphate pathway. In addition, we revealed that the delayed deterioration was attributed to MeJA treatment which stimulated the energy status of A. bisporus by reducing the respiration rate and nutrient decomposition, thus maintaining energy production. Our results provide a new insight into the role of MeJA treatment in delaying deterioration of A. bisporus through ATP production and supply.

Effect of nanocomposite-based packaging on microstructure and energy metabolism of Agaricus bisporus.

Rapid deterioration of postharvest Agaricus bisporus is a serious problem. Measures to improve the shelf-life are of great importance. Therefore, we used a nanocomposite-based packaging material (Nano-PM) containing nano-TiO2, nano-SiO2, nano-Ag and attapulgite to study its effect on microstructure and energy metabolism of A. bisporus. Nano-PM reduced the oxidation of lipids and proteins by activating antioxidant enzyme activities and inhibiting the accumulation of ROS, thereby maintained high level of energy status. Meanwhile, ATP content and energy charge of A. bisporus in Nano-PM increased through the energy metabolism system. This was attributed to the lower respiration rate and higher mitochondrial respiratory enzyme activities. These results indicated that Nano-PM could maintain the dense and intact microstructure of A. bisporus thus improve its shelf-life.

Effect of nanocomposite packaging on postharvest senescence of Flammulina velutipes.

A polyethylene based packaging material containing nano-Ag, nano-TiO2, nano-SiO2, and attapulgite has been prepared. The effect of nanocomposite packaging material (Nano-PM) on the senescence of Flammulina velutipes during 15 days of postharvest storage at 4 °C and a relative humidity of 90% were analyzed. The results showed that compared with normal packaging material (Normal-PM) and no packaging (No-PM), Nano-PM improved the appearance quality, reduced weight loss and cap opening. The degree of maturity and increase in molecular weight of F. velutipes polysaccharides (FVP) were delayed. The content loss of proteoglycan protein was less and degree of oxidation was lower. The storage with Nano-PM reduced the fibrosis of texture, cellulase activity, the accumulation of hydrogen peroxide (H2O2) and superoxide radical (O2-) by 18.9%, 48.3%, 26.6% and 27.8%, respectively (P < .05). The Nano-PM effectively delayed the postharvest senescence of F. velutipes, hence prolonged its shelf life and increased its preservation quality.