Xyloglucan in the primary cell wall: assessment by FESEM, selective enzyme digestions and nanogold affinity tags.

Xyloglucan has been hypothesized to bind extensively to cellulose microfibril surfaces and to tether microfibrils into a load-bearing network, thereby playing a central role in wall mechanics and growth, but this view is challenged by newer results. Here we combined high-resolution imaging by field emission scanning electron microscopy (FESEM) with nanogold affinity tags and selective endoglucanase treatments to assess the spatial location and conformation of xyloglucan in onion cell walls. FESEM imaging of xyloglucanase-digested cell walls revealed an altered microfibril organization but did not yield clear evidence of xyloglucan conformations. Backscattered electron detection provided excellent detection of nanogold affinity tags in the context of wall fibrillar organization. Labelling with xyloglucan-specific CBM76 conjugated with nanogold showed that xyloglucans were associated with fibril surfaces in both extended and coiled conformations, but tethered configurations were not observed. Labelling with nanogold-conjugated CBM3, which binds the hydrophobic surface of crystalline cellulose, was infrequent until the wall was predigested with xyloglucanase, whereupon microfibril labelling was extensive. When tamarind xyloglucan was allowed to bind to xyloglucan-depleted onion walls, CBM76 labelling gave positive evidence for xyloglucans in both extended and coiled conformations, yet xyloglucan chains were not directly visible by FESEM. These results indicate that an appreciable, but still small, surface of cellulose microfibrils in the onion wall is tightly bound with extended xyloglucan chains and that some of the xyloglucan has a coiled conformation.

Research on a new cationic polyacrylamide (CPAM) with a cationic microblock structure and its enhanced effect on sludge condition and dewatering.

Flocculation is one of the commonly used sludge conditioning methods in water supply plants, which can improve the sludge dewatering performance by reducing the specific resistance of sludge (SRF), decreasing the amount of sludge, and finally lowering the transportation cost and subsequent disposal cost of sludge. Therefore, it is particularly important to develop new and efficient flocculants. In this paper, the template copolymer of acryloxy trimethylammonium chloride (DAC) and acrylamide (AM) was successfully synthesized by microwave-template copolymerization (MV-TP) using sodium polyacrylate (NaPAA) as template. The template copolymer was analyzed by infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), nuclear magnetic resonance hydrogen spectroscopy (1H NMR), and scanning electron microscopy (SEM). It was found that this template copolymer had obvious cationic microblock structure. In addition, the test results of association constant (KM) and polymerization kinetics showed that the MW-TP was assigned to free radical initiated polymerization and the polymerization mechanism was I Zip-up (ZIP). It confirmed the formation of cation fragment structure again. Due to its dense positive charges in this new cationic microblock structure, it greatly improved the functions of electric neutralization, electrical patching, and adsorption bridging. The cationic fragment structure in the template copolymer could help to generate large and dense floc structure and form stable drainage channels. Under external pressure, these large and compact floc structures had greater compressive resistance, which avoided deformation and blockage of drainage channels and voids. It was beneficial to reduce SRF and evidently enhanced sludge dewatering performance.

A versatile CeO2/Co3O4 coated mesh for food wastewater treatment: Simultaneous oil removal and UV catalysis of food additives.

Food waste water is one of the most urgent environmental problems for the close connection between food and our daily life. Herein, we use a simple hydrothermal method to prepare a highly efficient catalyst-CeO2/Co3O4 compound on the stainless steel mesh, aiming for food waste water treatment. Possessing the superhydrophilic property and catalytic ability under ultraviolet light, CeO2/Co3O4 coated mesh has successfully processed three representative contaminants in food wastewater, which are soybean oil (food oil), AR (food dye) and VA (food flavor) simultaneously with an one-step filtration. Besides, the mesh is stable in a wide pH range and performs well in reusability. Therefore, such a multifunctional material with simple preparation method, high processing efficiency and facile operation shows a promising prospect for practical production and application for food wastewater treatment.

A Solvothermal Route Decorated on Different Substrates: Controllable Separation of an Oil/Water Mixture to a Stabilized Nanoscale Emulsion.

A facile solvothermal route is developed to fabricate polydivinylbenzene (PDVB) and decorate the polymer onto porous substrates. "Controllable" separation can be realized by selecting substrates with different pore sizes. The PDVB-modified mesh shows superhydrophobicity/superoleophilicity, and can be used for oil/seawater mixture separation, while the PDVB-modified membrane exhibits high hydrophobicity/superoleophilicity, and is able to separate surfactant stabilized nanoscale water-in-oil emulsions.

Improving the ordering and photovoltaic properties by extending π-conjugated area of electron-donating units in polymers with D-A structure.

A systematic molecular design process from PBDTTT-S to PBDTDTTT-S-T, a high-performance semiconducting polymer for organic photovoltaics, has been achieved by enhancing structural order, self-assembly and carrier mobility. Solar cells made from PBDTDTTT-S-T blended with PC(70) BM show a power conversion efficiency (PCE) of 7.81%, which is 25% higher than that of the parent PBDTTT-S.