Leaching and recovery of zinc from leaching residue of zinc calcine based on membrane filter press

The feasibility of leaching and recovery of zinc from zinc leaching residue （ZLR） based on a membrane filter press （MFP） was investigated. Experimental results show that zinc calcines with particle sizes of less than 106 μm and chambers of widths of 30 mm are appropriate for establishing uniform filter cakes to obtain acceptable leaching and recovery results. The leaching of zinc from ZLR performed via washing at 90 to 96 ℃ for 90 min with spent electrolyte using a MFP results in a zinc extraction rate of 97%, and almost all of the zinc leached are recovered after water washing with MFP, thereby avoiding any loss in the ZLR. Compared with the traditional hot concentrated acid leaching process, the process based on MFP as a leaching reactor is able not only to ensure a high extraction rate but also to reduce the leaching time. Moreover, the thickening, pulping, second leaching, washing, filtering and pressing could be integrated and realized using a single MFP.

Theoretical Study on Dynamic Filtration with the Membrane in Simple Harmonic Motion

A simple harmonic motion is proposed to make the membrane move in a simpleharmonic way so as to enhance the membrane filtration, and minimize the membrane fouling andconcentration polarization. The velocity distribution and pressure distribution are deduced from theNavier-Stokes equation on the basis of a laminar flow when the membrane rotates at the speed of Asin(αt). And then the shear stress, shear force, moment of force on the membrane surface and powerconsumed by viscous force are calculated. The velocity distribution demonstrates that the phase ofmembrane velocity does not synchronize with that of shear stress. The simple harmonic motion canresult in self-cleaning, optimize energy utilization, provide the velocity field with instability,and make the feed fluid fluctuation. It also results in higher shear stress on the membrane surfacethan the constant motion when they consume the same quantitative energy.

Self-assembled Cyclodextrin Metal-Organic Frameworks on Graphene Oxide as Filter Membrane for Tracelevel Naringin Pre-enrichment before Analysis

A green,renewable composite was designed and fabricated based on self-assembly of cyclodextrin metal-organic framework(CD-MOF)on graphene oxide(GO).Then,the GO@CD-MOF was embedded in 0.45μm PTFE membrane to produce a dual-functional membrane which could carry out sample enrichment by capturing naringin molecules.The membrane filter was further improved by investigating the effects of the experimental parameters including amount of GO@CD-MOF,enrichment time and elution solvent on enrichment efficiency of naringin.Further,the present method had been successfully applied to citrus sample and obtained satisfied recovery value(79.7%-100.3%).Moreover,the extraction of naringin can be achieved for 2 min,and GO@CD-MOF loaded membrane can be reused at least for 5 times.The results demonstrate that the fabrication of the novel filter membrane based on GO@CD-MOF is a fast,simple and reliable,and possesses great potential in the determination of naringin from real samples by dual-function of separation and enrichment.

EFFECTS OF FILTER MEMBRANES ADSORBING INFLAMMATORY MEDIATORS IN HEMOFILTRATI ON

Objective In this study, an in vitro hemofiltration model was set up to investigate adsorptive saturati on time of different membrane under different blood flow rate (Q B)and filt rate rate(Q F). Methods Anticoagulated cattle blood (2000 mL per bag) was stimulated with 1μg·mL -1 endotoxin to induce i nflammatory mediators before hemofiltration (HF) using AN69, PS and PMMA filters in vitro. Adsorptive saturation time of membrane was observed using data br idge in different Q B and different Q F. TNF was measured by radioimmu noassays. Results Before the resistance level reached the peak value in the same group, resistance level increased significantly (P<0.01). After the peak value, there was no difference (P>05). It was suggested tha t the resistance level reached plateau at 150,120,90,120, and150 minutes in Q F of 100 mL·minute -1, 200 mL·minute -1, 300 mL·minute -1 , respectively and in Q F of 1L·hour -1, 2L·hour -1, 4L·hour -1, respectively. And with the Q B and Q F increasing, resistanc e level increased significantly (P<0.01) among different groups at the same time point in A, B, C, D and E group. Conclusion Membrane resis tance level online measured by Data Bridge can instantly reflect the degree of m embrane adsorption. Adsorptive saturation time of filter membrane in different f iltration flow rate and blood flow rate are different.

Research on Distribution Regularities of Dust Concentration and Granularity in Large Mining Height Working Face

The key for dust control of coal mine is to clarify the dust concentration distribution and sedimentation in different areas. Both similarity experiment and numerical simulation method have certain restrictions and are quite different from the actual situation on site. In order to study the dust sedimentation regularity of coal mine in large mining height, “filter membrane method” is adopted in this paper, i.e., to dry and weigh the filter membrane before and after sampling, collect the dust of respirable zone on mining face and calculate the dust concentration based on a main airway of 100 m. The result shows that: A large amount of dust will be produced during coal mining, wherein the maximum dust concentration from 6 m upstream to 100 m downstream of coal cutter is 121 mg/m3, while the minimum dust concentration is 61 mg/m3;The dust concentration in return airway is reduced with the distance increases, while the dust concentration at the entrance is 91 mg/m3;A large amount of dust may fall from roof during section advancing and improves the dust concentration of hydraulic support in walking area obviously;The dust granularity of mining face and return airway is 0 - 100 μm, but the amount of respirable dust is higher than 80%, the larger the dust particle size, the higher the dust concentration. Besides, dust in small particle size can be suspended in air flow for longer, but that in large particle size may subside under the action of gravity;To reduce dust exposure, the mining position shall be located in the windward direction of advancing or coal cutter. This research can provide guidance for taking dust prevention measures of working face in large mining height.

Integration of filter membrane and Ca_(2)Nb_(3)O_(10) nanosheets for high performance flexible UV photodetectors

We report that the integration of filter membrane and Ca_(2)Nb_(3)O_(10)nanosheets(FM@CNO) UV photodetector(UV PD) shows high performance and excellent flexibility. The Ca_(2)Nb_(3)O_(10)nanosheets were prepared by a facile solid-state reaction and liquid exfoliation process. The Ca_(2)Nb_(3)O_(10)nanosheets can be integrated into the pores of a filter membrane via a simple vacuum filtration method. The FM@CNO UV PD shows high performance under 300 nm light illumination at 5 V bias, including high responsivity(0.08 AW^(-1)), high detectivity(1.1 × 10^(12)Jones), high UV/visible rejection ratio(3.86 × 10^(3)) and fast speed(0.12/1.24 ms). Furthermore, the FM@CNO device exhibits excellent flexibility after many bending cycles.In addition, the FM@CNO array device was used as a pixel array detector for UV imaging. This work provides a novel approach to achieve high performance flexible PDs based on filter membrane and two dimensional materials.

A Self-supporting,Surface Carbonized Filter Paper Membrane for Efficient Water-in-Oil Emulsion Separation

Due to the important role of oil source in our life,the separation of water-in-oil emulsion is urgent and necessary.Membrane seperation technology has been an efficient and widely used method in separating oil-water separation.Herein,we report a versatile approach to fabricate surface carbonized membranes with self-standing property from biomass-derived precursor by synergistic charring of phytic acid,arginine and filter paper.The obtained membrane exhibited superhydrophobicity in oil,excellent fouling resistance,and self-supporting ability.The membrane can be cycle-used at least 12 times with high permeation flux(up to 1380 L·m^(-2)·h^(-1))and separation efficiency(up to 99.4%).

Extraction of 17β-estradiol in water using non-imprinted polymer submicron particles in membrane filters

17β-Estradiol （E2） is an endocrine disrupting chemical of harm to both animals and human beings at a low concentration level （ng/L）. It cannot be completely removed by wastewater treatments, and is often detected in both environment and drinking waters. The purpose of this feasibility study, towards environmental engineering in the field of water analysis and treatment, was to remove E2 by extraction using non-imprinted polymer （NIP） submicron particles. Experimental results showed that 0.5 mg/L of E2 could be completely extracted by adding 10 mg of NIP particles directly into 10 mL of water. However, the extraction efficiency decreased to 64% for 100 mL of water. prefilling the NIP particles inside a membrane filter showed a potential for water treatment of a large volume, requiring no effort to distribute the particles uniformly in the water. High extraction efficiency （80 ± 10）% for E2 was achieved for 100 mL of water. A total mass of 0.29 mg E2 was extracted from 1000 mL of water containing 0.8 mg/L E2 （by using only 10 mg of NIP particles）. Both efficiency and mass capacity can be increased, by scaling up the amount of NIP particles, towards environmental engineering applications.

Robust nanoporous Cu/TiO_(2) ceramic filter membrane with promoted bactericidal function

Filter membrane technology has been extensively used for water purification.However,due to their high brittleness and biological fouling,filter membranes will gradually deteriorate.Here we develop a robust Cu/TiO_(2) ceramic filter membrane for water treatment,which has excellent inherent antibacterial activities both in the dark and under visible light irradiation.Onedimensional nanobelt TiO_(2) can be sintered into a nanoporous membrane structure by overlapping and interweaving with each other,thereby achieving high flux simultaneously and solving the problem of high brittleness of inorganic ceramics.Meanwhile,such one-dimensional TiO_(2) nanostructures can provide more deposition sites for Cu nanoparticles with inherent antibacterial activity in the dark.To realise the surface plasmon resonance-enhanced antibacterial activity under visible light,Cu/TiO_(2) heterostructures are used.

High Q reflection filter using a gradient-index membrane with a grating surface

High Q reflection filter using a gradient-index(GI) membrane with a grating surface is proposed. The thickness of GI membrane is very small comparing with the traditional multilayer reflection filter or the GI reflection filter, and the GI membrane can also break the restriction of the resonant excitation condition of the conventional guided-mode resonance(GMR) filter. High Q filtering features can be maintained even on the high-index substrate. The grating thickness of the GI membrane filter can be used to select the resonance wavelength with different quality factors(QFs), the reflection peak is blue-shifted, and the QF is decreased from 554.4 to 207.8 as the grating thickness is increased from 50 nm to 150 nm. The gradient coefficient of the GI membrane filter can be used to tailor the number of the reflection channels. The resonant excitations of high order waveguide modes confined in the GI membrane are responsible for the high Q filtering properties with multiple channels.