Innovative method of culturing bdelloid rotifers for the application of wastewater biological treatment

• An innovative method of culturing bdelloid rotifer fed on flour was proposed. • Rotifer fed on flour grew faster than that fed on bacteria or Chlorella vulgaris. • The optimum mass culture conditions for rotifer fed on flour were investigated. • The cultured rotifer could improve sludge settleability in the SBR. This study aims to establish a simple and efficient method for the mass culture of bdelloid rotifers, which is the basis for the application of bdelloid rotifers as biological manipulators to improve wastewater biological treatment performance. A common bdelloid rotifer, Habrotrocha sp., in a wastewater biological treatment system was selected as the culture target. Rotifers fed on flour could reproduce faster than those fed traditional food such as Chlorella vulgaris or mixed bacteria. As a rotifer food, flour has the advantages of simple preparation, effortless preservation, and low cost compared to live Chlorella vulgaris or mixed bacteria, so it is more suitable for the mass culture of rotifers. The optimal rotifer culture conditions using flour as food were also studied. According to the experimental results, the recommended rotifer culture conditions are a flour particle size of 1 μm, a flour concentration of 6 × 10⁶ cell/mL, a temperature of 28℃, a pH level of 6.5 and salinity of 100–500 mg/L. In addition, the sludge volume index in the sequencing batch reactor (SBR) with the addition of cultured rotifers was 59.9 mL/g at the end of operation and decreased by 18.2% compared to SBR without rotifer, which indicates that the cultured rotifers still retained the function of helping to improve sludge settling. This function may be related to the rotifer’s role in inhibiting bacteria from producing loosely bound extracellular polymeric substances in the SBR.     

Recyclable Fe3O4@Polydopamine (PDA) nanofluids for highly efficient solar evaporation

Volumetric solar evaporations by using light-absorbing nanoparticles suspended in liquids (nanofluids) as solar absorbers have been widely regarded as one of the promising solutions for clean water production because of its high efficiency and low capital cost compared to traditional solar distillation systems. Nevertheless, previous solar evaporation systems usually required highly concentrated solar irradiation and high capital cost, limiting the practical application on a large scale. Herein, for the first time in this work, polydopamine (PDA)-capped nano Fe3O4 (Fe3O4@PDA) nanofluids were used as solar absorbers in a volumetric system for solar evaporation. The introduction of organic PDA to nano Fe3O4 highly contributed to the high light-absorbing capacity of over 85％in wide ranges of 200–2400 nm because of the existence of numerous carbon bonds and pi (π) bonds in PDA. As a result, high evaporation efficiency of 69.93％under low irradiation of 1.0 kW m-2 was achieved. Compared to other nanofluids, Fe3O4@PDA nanofluids also provided an advantage in high unit evaporation rates. Moreover, Fe3O4@PDA nanofluids showed excellent reusability and recyclability owing to the preassembled nano Fe3O4, which significantly reduced the material consumptions. These results demonstrated that the Fe3O4@PDA nanofluids held great promising application in highly efficient solar evapo-ration.     

Improving the stability,lithium diffusion dynamics,and specific capacity of SrLi2Ti6O14 via ZrO2 coating

SrLi2Ti6O14 (SLTO) coated with different amount of ZrO2 was successfully prepared. The as-obtained composites are stacked by a series of particles with a pure phase structure and a good crystallinity. Furthermore, ZrO2 coating not only enhances the structural stability of the materials but also facilitates the diffusion of lithium through the SEI film. As a result, the redox polarization was reduced, and the reversibility of the electrochemical reaction was enhanced. Particularly, SLTO-ZrO2-2 sample delivers a high initial lithiation capacity of 283.6 mA h g-1, and the values maintain at 251.7, 228.0, 207.4, 175.3, and 147.7 mA h g-1 at the current densities of 0.13, 0.26, 0.54, 1.31, and 2.62 A g-1, respectively. Our experiment also confirmed that SLTO materials coated with ZrO2 are suitable for high power density applications, and the lithiation specific energy efficiency of SLTO-ZrO2-2 is 200％as high as that of pure SLTO at a power density of 1257 W kg-1.     

Construction of MoS2 nanoarrays and MoO3 nanobelts: Two efficient adsorbents for removal of Pb（Ⅱ）, Au（Ⅲ） and Methylene Blue

Toxic heavy metal ions, valuable noble metal ions and organic dyes are significant concerns in wastewater treatment. In this work, MoO₃ nanobelts（MoO₃ NBs） prepared by solvothermal method and MoS₂ nanoarrays（Mo S₂ NAs） constructed using MoO₃NBs precursor were proposed to effectively remove heavy/noble metal ions and organic dyes, such as Pb^（Ⅱ）, Au^（Ⅲ）and Methylene Blue（MB）. The two adsorbents exhibited the excellent adso...