The Effect of Ball Milling Time on the Isolation of Lignin in the Cell Wall of Different Biomass

Ball milling technology is the classical technology to isolate representative lignin in the cell wall of biomass for further investigation. In this work, different ball milling times were carried out on hardwood (poplar sawdust), softwood (larch sawdust), and gramineous material (bamboo residues) to understand the optimum condition to isolate the representative milled wood lignin (MWL) in these different biomass species. Results showed that prolonging ball milling time from 3 to 7 h obviously increased the isolation yields of MWL in bamboo residues (from 39.2% to 53.9%) and poplar sawdust (from 15.5% to 35.6%), while only a slight increase was found for the MWL yield of larch sawdust (from 23.4% to 25.8%). Importantly, the lignin substructure of ß-O-4 in the MWL samples from different biomasses can be a little degraded with the increasing ball milling time, resulting in the prepared MWL with lower molecular weight and higher content of hydroxyl groups. Based on the isolation yield and structure features, milling time with 3 and 7 h were sufficient to isolate the representative lignin (with yield over 30%) in the cell wall of bamboo residues and poplar sawdust, respectively, while more than 7 h should be carried out to isolate the representative lignin in larch sawdust.

Graphene-based composite membranes for nanofiltration: performances and future perspectives

Nanofiltration is one of the most widely used membrane processes for water purification with high practical value because of a large number of chemical species that are separated through this process. Usually, for nanofiltration, high energy–consuming operations are involved including the generation of enough pressure for the rejection of jumps and lower molecular weight chemicals at the surface of the membrane. Recent developments in the synthesis of nanocomposite membranes with graphene and graphene derivatives have led to an increase in energy requirements and the increase in membranes performances. In the present review, we have presented the recent advances in the field of graphene-based composite membranes for nanofiltration with applications for both types of based solvents—aqueous solutions and organic solvents. The presentation will be focused especially on the performances of membranes and applications of these materials for the rejection of salts (Na+, Mg2+), heavy metals (Li2+), and lower molecular weight organic compounds (methylene blue, Congo red, Direct Red, Methyl orange, Reactive green 13, etc.). Modern synthesis methods like interfacial polymerization for obtaining thin-film composite nanofiltration membranes are also presented.

Use of an Ultraviolet Light activated Persulfate Process to Degrade Humic Substances: Effects of Wavelength and Persulfate Dose

Natural organic matter (NOM), commonly found in surface and ground waters, form Disinfection by-products in drinking water. Generally, advanced oxidation processes (AOPs) featuring hydrogen peroxide are used to treat water, however, sulfate radical recently has been used to treat recalcitrant organics, because it is associated with a higher oxidation potential and more effective removal than hydroxyl radicals. Hence, in this research, we evaluated persulfate oxidation efficiency in terms of reductions in humic substances levels and investigated the degradation mechanism. The results showed that ultraviolet activated persulfate effectively treated humic substances compared with hydrogen peroxide and direct irradiation. Treatment was dose- and wavelength-dependent; higher persulfate concentrations or shorter UV wavelengths were more effective for treating humic substances as high concentration sulfate radicals were created. The degradation mechanism was similar to that of hydrogen peroxide. Aromatic and chromophore components were more susceptible to degradation than were lower molecular weight components, being initially decomposed into the latter, reducing UV254 absorbance and the SUVA254. Lower molecular weight materials were eventually degraded to end products: NPOC levels fell. And we also treated the inflow of a drinking water treatment plant with persulfate, and humic substances were effectively removed.

A study on the dispersion of I30E nanoclay in epoxy resin and bitumen matrix

Dispersion of nanoclay in Epikote 828 resin is conducted by closed mixing of the liquid composition, mechanical mixing combined with ultrasonic vibration to form masterbatch; meanwhile, nanoclay dispersion in bitumen is processed by melted bitumen mixing. XRD techniques were used to determine the basal d-spacing of nanoclay. The dispersion was performed in Brabender mixer at temperature 40oC, speed 50 rpm, an Epikot/I30E=100/80 masterbatch provided the best dispersion with d001=33.818 Å. After mechanical mixing, an Epikote 828 composition with 4% I30E was sonicated for 5, 10, and 20 minutes. The value d001=41.65 Å achieved after 10 minutes of sonication was deemed optimal. Dispersion of 4% I30E in melted bitumen at 120, 130, 140, 150, and 160oC after 2h reached d001=49.5916 Å for the sample processed at 120oC. At high temperatures, penetration and delamination of bitumen were better than those of Epikote 828 despite the lower molecular weight of Epikote.

Neuroprotection mediated by ST266 requires full complement of proteins secreted by amnion-derived multipotent progenitor cells

ST266 is the biological secretome of cultured Amnion-derived Multipotent Progenitor cells containing multiple growth factors and cytokines. While intranasally-administered ST266 improves the phenotype in experimental optic neuritis, specific ST266 components mediating these effects are not known. We compared the effects of ST266 with and without removal of large molecular weight proteins both in vitro and in the multiple sclerosis model experimental autoimmune encephalomyelitis (EAE) in C57BL/6J mice. Mice were treated daily with intranasal vehicle, ST266 or lower molecular weight fraction of ST266. Retinal ganglion cells were counted in isolated retinas, and optic nerves were assessed for inflammation and demyelination. ST266 treatment significantly improved retinal ganglion cell survival and reduced optic nerve demyelination in EAE mice. The lower molecular weight ST266 fraction significantly improved optic nerve demyelination, but only showed a trend towards improved retinal ganglion cell survival. ST266 fractions below 50kDa increased Schwann cell proliferation in vitro, but were less effective than non-fractionated ST266. Demyelination attenuation was partially associated with the lower molecular weight ST266 fraction, but removal of higher molecular weight biomolecules from ST266 diminishes its neuroprotective effects, suggesting at least some high molecular weight proteins play a role in ST266-mediated neuroprotection.

HEMOGLOBIN ISOFORMS AND ERYTHROCYTE HETEROGENEITY

The work shows changes in the ratio of blood hemoglobin isoforms and of bone marrow their distribution by types of erythrocytes. One erythrocytes carries two isoforms of hemoglobin. Erythrocytes with a lower molecular weight contain a lower percentage of acid- and alkali-resistant properties.

Optimization of Degradation Conditions with PRG, a Polysaccharide from Phellinus ribis, by RSM and the Neuroprotective Activity in PC12 Cells Damaged by Aβ25–35

In the previous work, we found PRG, a polysaccharide from Phellinus ribis, exhibited neurotrophic activity. To obtain an active structural unit with lower molecular weight, PRG was degraded to prepare the degraded PRG (DPRG) using ascorbic acid and H2O2. The aim of the paper was to obtain DPRG by optimizing the degradation conditions using response surface methodology (RSM) and to study its protective effects of PC12 cells induced by Aβ25–35. The optimum conditions were as follows; the concentration of H2O2-Vc was 17 mM and degradation temperature was 50 °C; when degradation time was 1.6 h, the experimental response value of PC12 cell viability was 83.4 ± 0.15%, which was in accordance with the predicted value (83.5%). We also studied the protective effects of DPRG against the Aβ25–35-induced neurotoxicity and explored the underlying mechanism. The results showed that treatment with DPRG could attenuate PC12 cells death. The mechanism was relative to the inhibition of cell apoptosis by increasing the MMP level and decreasing the protein expression of cytochrome C (Cytc) in PC12 cells. In conclusion, DPRG with lower molecular weight was obtained successfully. It possessed neuroprotective properties and might be a candidate for neurodegenerative disease treatment.

The Influence of Graft Length and Density on Dispersion, Crystallisation and Rheology of Poly(ε-caprolactone)/Silica Nanocomposites

Different techniques of grafting polymer chains to filler surfaces are often employed to compatibilise filler and polymer matrices. In this paper the influence of graft length and graft density on the state of dispersion, crystallisation and rheological properties of poly(ε-caprolactone) (PCL)/silica (SiO2) nanocomposites are reported. Grafted silica nanoparticles were prepared through polymerisation of PCL from the nanoparticle surface. Graft length was controlled by the reaction time, while the grafting density was controlled by the monomer-to-initiator ratio. Grafted nanoparticles were mixed with PCL of different molecular weights and the state of dispersion was assessed. Different matrix-to-graft molecular weight ratios resulted in different states of dispersion. Composites based on the higher molecular weight matrix exhibited small spherical agglomerates while the lower molecular weight matrix revealed more sheet-like microstructures. The state of dispersion was found to be relatively independent of graft length and density. Under quiescent conditions the grafts showed increased nucleation ability in the higher molecular weight PCL, while in the lower molecular weight matrix the effect was less pronounced. Rheological experiments showed an increase in viscosity with increased filler content, which was beneficial for the formation of oriented structures in shear-induced crystallisation.