Enhancement of anaerobic digestive efficiency by the use of exchange resin to remove cations in sewage sludge

<p>Hydrolysis is considered as the rate-limiting stage of anaerobic digestion which is one of the most applied stabilization processes in the disposition of sludge. It is urgent to accelerate the hydrolysis of the sludge particles and improve its biodegradability. This study utilized cation-exchange resin (CER) to adsorb divalent cations in the supernatant of activated sludge with the purpose of making the sludge floc disintegrated. The results showed that the biopolymers incorporated in the tightly bound extracellular polymeric substances can be released to the bulk using CER to remove cations. However, the lack of essential elements led to a much lower methane yield of treated sludge than that of activated sludge. The treated sludge got a higher methane production rate constants after added Fe²⁺. It is necessary to add Fe²⁺ or regenerated liquid of resin-containing essential elements in order to maintain the activities of microbial life.</p

Reprogrammable Logic Gate and Logic Circuit Based on Multistimuli-Responsive Raspberry-like Micromotors

In this paper, we report a polymer-based raspberry-like micromotor. Interestingly, the resulting micromotor exhibits multistimuli-responsive motion behavior. Its on–off–on motion can be regulated by the application of stimuli such as H₂O₂, near-infrared light, NH₃, or their combinations. Because of the versatility in motion control, the current micromotor has great potential in the application field of logic gate and logic circuit. With use of different stimuli as the inputs and the micromotor motion as the output, reprogrammable OR and INHIBIT logic gates or logic circuit consisting of OR, NOT, and AND logic gates can be achieved

Effect of Increasing Total Solids Contents on Anaerobic Digestion of Food Waste under Mesophilic Conditions: Performance and Microbial Characteristics Analysis

<div><p>The total solids content of feedstocks affects the performances of anaerobic digestion and the change of total solids content will lead the change of microbial morphology in systems. In order to increase the efficiency of anaerobic digestion, it is necessary to understand the role of the total solids content on the behavior of the microbial communities involved in anaerobic digestion of organic matter from wet to dry technology. The performances of mesophilic anaerobic digestion of food waste with different total solids contents from 5% to 20% were compared and the microbial communities in reactors were investigated using 454 pyrosequencing technology. Three stable anaerobic digestion processes were achieved for food waste biodegradation and methane generation. Better performances mainly including volatile solids reduction and methane yield were obtained in the reactors with higher total solids content. Pyrosequencing results revealed significant shifts in bacterial community with increasing total solids contents. The proportion of phylum <i>Chloroflexi</i> decreased obviously with increasing total solids contents while other functional bacteria showed increasing trend. <i>Methanosarcina</i> absolutely dominated in archaeal communities in three reactors and the relative abundance of this group showed increasing trend with increasing total solids contents. These results revealed the effects of the total solids content on the performance parameters and the behavior of the microbial communities involved in the anaerobic digestion of food waste from wet to dry technologies.</p></div

Polymer Single Crystal As Magnetically Recoverable Support for Nanocatalysts

In this Letter, we report, for the first time, using polymer single crystal as magnetically recoverable support for nanoparticle catalysts. This catalyst system is composed of polymer single crystal, platinum nanoparticles, and iron oxide nanoparticles, which act as support, catalysts, and magnetic responsive materials, respectively. Platinum nanoparticles and iron oxide nanoparticles were bonded onto thiol groups and hydroxyl groups on a tailor-designed polymer single-crystal surface. Because of its quasi 2D nature, polymer single crystal possesses high surface area to volume ratio (2.5 × 10⁸ m^–1), which is ∼40 times higher than its nanosphere counterpart of the same volume. This high surface to volume ratio facilitates the high loading of both nanoparticles, which ensures efficient catalytic reaction and reliable nanoparticle recycling. Synergetic interactions between platinum and iron oxide nanoparticles also led to further improvement in catalytic activity

Schematic of oxygen microprofiles around submerged macrophyte leaves with periphyton.

<p>Schematic of oxygen microprofiles around submerged macrophyte leaves with periphyton.</p

Microprofiles of pH around <i>Potamogeton malaianus</i> stems and leaves with and without periphyton.

<p>A, C, and E, indicate thick periphyton; B, D, and F indicate periphyton removed; G indicates young leaves with a little periphyton. Microprofiles were measured at three different points under quantum flux density of 300 µmol photons·m^–2·s^–1 on <i>P. malaianus</i> stems and leaves. The outer surfaces of the periphyton layer are indicated by horizontal bars. The leaf surfaces are indicated by 0. The microprofiles of pH around young leaves were not markedly different between the presence of little periphyton and periphyton removed.</p

Taxonomic compositions of bacterial communities at phyla level in each sample retrieved from pyrosequencing.

<p>Taxonomic compositions of bacterial communities at phyla level in each sample retrieved from pyrosequencing.</p

In Situ Generation of Copper Species Nanocrystals in TiO₂ Electrospun Nanofibers: A Multi-hetero-junction Photocatalyst for Highly Efficient Water Reduction

Engineering the multi-hetero-junctions in semiconductor photocatalysts has been recognized as a promising way to achieve highly efficient photocatalytic solar-fuel generation, because the photoinduced heterointerfacial charge transfer can greatly hinder the recombination process of charge-carrier in photocatalysts. In this work, we fabricated copper species nanocrystals/TiO₂ multi-hetero-junction photocatalysts through in situ reduction of CuO nanocrystals in CuO/TiO₂ electrospun nanofibers by a hydrothermal method assisted by glucose. By changing the concentration of glucose, the composition ratio of copper species nanocrystals, including CuO, Cu₂O, and Cu, can be adjusted in multi-hetero-junction nanofibers. Upon simulated sunlight irradiation, the optimal copper species nanocrystals/TiO₂ multi-hetero-junction nanofibers exhibited an H₂ evolution rate of ∼10.04 μmol h^–1, a 17.3 times increase over that of bare TiO₂ nanofibers (∼0.57 μmol h^–1)

Reprogrammable Logic Gate and Logic Circuit Based on Multistimuli-Responsive Raspberry-like Micromotors

In this paper, we report a polymer-based raspberry-like micromotor. Interestingly, the resulting micromotor exhibits multistimuli-responsive motion behavior. Its on–off–on motion can be regulated by the application of stimuli such as H₂O₂, near-infrared light, NH₃, or their combinations. Because of the versatility in motion control, the current micromotor has great potential in the application field of logic gate and logic circuit. With use of different stimuli as the inputs and the micromotor motion as the output, reprogrammable OR and INHIBIT logic gates or logic circuit consisting of OR, NOT, and AND logic gates can be achieved

Characteristics of the substrates and inoculums.

<p>–Not determined.</p>a<p>FW: food waste.</p>b<p>TS: total solids.</p>c<p>VS: volatile solids.</p>d<p>TAN: total ammonia nitrogen.</p