Sieve Size Research Articles

Stiffness evaluation of coarse unbound granular materials using large-scale repeated load triaxial test

This research investigates the effect of downscaling coarse unbound granular material (UGM) for characterization of the resilient modulus with large-scale repeated load triaxial testing. Four open-graded and two dense-graded materials are downscaled based on the particle size distribution curve and upper sieve size for subbase materials of crushed rock (CR) 22/125 mm and CR 0/125 mm as defined by the Norwegian road design regulation.The results were evaluated using the K-θ model and Uzan’s model. The findings for CR 4/22 mm, CR 6/32 mm, CR 8/45 mm, and CR 11/63 mm indicate that downscaling of coarse open-graded UGMs could be applicable for characterization of the resilient modulus. The results for dense-graded UGMs CR 0/22 mm and CR 0/63 mm indicate that downscaling reduces the resilient modulus. Further research should include complementary gradings and rock types.

Fatty acid composition, lipid profile and oxidative stability of meat of broiler chickens fed diet containing bird eye pepper of varying inclusion level and sieve size.

Nutritional modifications to improve meat quality is targeted by farmers. Bird eye pepper (BEP) contains bio-compounds of physiological significance. The potency of BEP of varying inclusion level and sieve size on meat quality [fatty acid (FA), lipid profile and oxidative stability] of broiler chickens was investigated. A total of 246 birds fed diet-containing BEP [inclusion level (0, 0.15 and 0.3%), sieve size (0.05 and 0.1mm)] were randomized to six treatments replicated 4 times in a 2 by 3 factorial layout. After feeding (31 days), forty-eight birds (two per replicate) were slaughtered and breast muscles harvested. Meat lipid profile and 2-thiobarbituric acid reactive substance (TBARs) were determined on day (d) 0, while TBARs was further assessed on d 3 and 5, but FA on d 10 of refrigeration storage. BEP diet (0.15%) increased (p < 0.05) total monounsaturated FA (MUFA), unsaturated FA (UFA) and n-3 FA, while 0.05mm BEP lowered (p < 0.05) meat index of thrombogenicity (TI) but increased meat hypocholesteromic: hypercholesteromic (HH) value. Dietary 0.15% (0.05mm) BEP yielded low (p < 0.05) SFA but high MUFA: SFA, UFA: SFA and NVI, while 0.15% (0.1mm) BEP diet resulted in high total MUFA and higher (p < 0.05) UFA, n-3 and n-3: n-6 FA. Control, 0.15% and 0.05mm BEP diets reduced (p < 0.05) meat cholesterol value. This study has shown that 0.15% (0.05mm) BEP diet had no deleterious effect on the growth of broiler chickens but improved the NVI, IA, TI, HH, TBARs and cholesterol of the meat - a significance to health-conscious consumers.

Experimental investigation on suppression effect of molecular sieve powders on asphalt fume

The tremendous emission of asphalt during pavement construction has been posing significant health hazards and environmental pollution. Molecular sieves such as homogeneous porous powders possess the potential to suppress asphalt fume. However, the effective reduction of asphalt emissions via porous materials is limited owing to the lack of understanding of their absorption mechanism. This study investigated a series of molecular sieve powders (3A, 5A, 10X, 13X, NaY, MCM-41-Al and MCM-41-Si) for fume suppression, including their micromorphology, pore characteristics, pollutants emission concentrations, organic volatile compositions, and rheological properties by comparing pristine asphalt and the molecular sieves modified asphalt. The results indicated that molecular sieves could effectively suppress 69.5–83.2% of volatile organic compounds (VOC) emissions and absorb nearly all the NO, H2S, and SO2. Adsorption mechanism of asphalt fume by molecular sieves was mainly depends on polarity of molecules size and relationship. Pollutants with higher polarity could be well absorbed. Pore size of molecular sieves needed to be slightly larger than the width of targeted pollutant molecules to absorb them and suppress the emissions. This study attributed molecular characteristics of the main pollutants, the adsorption mechanism of porous materials and effective asphalt fume reduction with molecular sieves, which supports future research on practical technologies for asphalt fume suppression.

Hydrothermally rearranged cellulose membranes for controlled size sieving

Biodegradable polymers are important for reducing pollution and promoting sustainability as they break down more easily than traditional petroleum-based polymers. One such polymer is regenerated cellulose (RC), which is widely used in water purification and pharmaceuticals due to its chemical resistance and hydrophilicity. Since its direct use of cellulose is limited by its insolubility, derivatives like cellulose acetate (CA) are first converted through a regeneration process back into RC to make use of its functional properties. During this process, however, the membrane structure may be compromised, impairing its separation performance. Here we show that simply soaking CA membranes in hot water before regeneration significantly improves the structural integrity of RC membranes, retaining the sieving properties. The pretreatment causes planar shrinkage without disrupting the general characteristics of cellulose, allowing for sole adjustment of pore size. This straightforward approach enables precise tuning of membrane pore properties to suit specific application, such as adjusting pore size for efficient sieving of materials with particular molecular masses, all while maintaining high water permeance. Our findings suggest that hydrothermal processing has the potential to enhance the filtration performance of RC membranes and broaden their range of applications.

Polyelectrolyte-modified covalent organic framework membranes for multivalent cation removal

Covalent organic framework (COF) has become a promising membrane material in chemical separations. However, the application of COF membranes for ion separation is still challenging, due to the mismatch between the pore size of COFs (1–5 nm) with the diameter of hydrated ions (<1 nm). Herein, a cationic polyelectrolyte surface modification strategy of COF membranes was proposed, by assembling a cationic polyelectrolyte (PEI, PDDA, PAH) layer on the surface of an anionic COF (TpPa-SO3H) membrane via dip coating. The cationic polyelectrolytes on the membrane surface offered abundant positive charges and reduced the surface pore size, leading to the synergistic enhancement of the size sieving and the electrostatic repulsion. Accordingly, effective rejection of multivalent cations was realized with a significantly increased rejection rate of 97.1 % for MgCl2, compared to that of TpPa-SO3H membrane (10.3 %). Furthermore, the polyelectrolyte-modified COF membrane exhibited desirable separation performance for heavy metal ions in water. The rejection rates for heavy metal salts, including CrCl3, CdCl2, CuCl2, PbCl2 and NiCl2, reached 98.5 %, 97.3 %, 97.0 %, 96.2 %, and 96.0 %, respectively, and remained above 95 % during the 7-day long-term operation test.

Elucidating the separation role of C3N slit-pore on N2/CH4 in coalbed methane

A hybrid approach integrating molecular dynamics (MD) and Grand Canonical Monte Carlo (GCMC) simulations was employed to investigate the separation efficacy of N2/CH4 across various C3N slit apertures. MD simulations enabled the determination of separation selectivity and diffusion coefficients of N2/CH4, thereby aiding in the elucidation of the separation mechanism. On the other hand, GCMC simulations provided insights into the adsorption isotherms and isosteric heats of N2 and CH4 within the C3N slit. These findings reveal that the highest selectivity of N2 over CH4 occurs at the zigzag-edge C3N with a pore size of 6.2 Å. However, this selectivity is accompanied by the smallest diffusion coefficient, attributable to size sieving effects. As the pore diameter increases, more gas molecules can permeate into the pores, leading to a rise in both the maximum adsorption capacity and the isosteric heat of methane adsorption. With increasing pressure, gas molecules tend to reach saturation at higher pressure levels. Our study primarily centers on examining the separation of N2/CH4 across various C3N slit-pores, encompassing both adsorption and diffusion phenomena. These findings offer theoretical insights and comprehension for the experimental separation of coalbed methane utilizing cheaper carbon-based materials.

Characterization and acid leaching beneficiation studies of Anka (Zamfara State, Nigeria) copper ore deposit

The chemical and mineralogical characterization of the Anka copper was examined and its susceptibility to H2SO4 acid leaching was assessed. A crude sample of the ore, weighing 5 kg, was sourced from the mines, communiated, homogenized, and characterised the crude sample. A 100 g fraction of the crushed sample was subjected to fractional sieve analysis and each sieve retained was chemically analysed. The leaching process was carried out on 100 g of -125+90 µm sieve size fraction using H2SO4 acid and the resulting product was chemically analyzed. The characterization result reveals 42.271% CuO using the energy dispersive x-ray fluorescence spectrometer and the x-ray diffractometer shows that the ore is mainly composed of Cu-carbonate hydroxide in the form of malachite mineral. The scanning electron microscope micrograph suggests that the ore contains dispersed grains of sodium aluminium silicate and copper carbonate hydroxide in a silica-dominated matrix. The ore's liberation size was determined to be at the sieve size of -125+90 μm. Finally, the ore was discovered to be responsive to the H2SO4 acid leaching operation, leading to an enrichment of the feed from 42.27% Cu to a pregnant solution of 52.51% Cu and the residue from the leaching was analyzed to be 4.69% Cu.

Highly selective removal of thallous ions from wastewater using Prussian Blue biochar composite

Thallium, a highly toxic pollutant, shows greater toxicity to human than other common heavy metals such as mercury, lead, cadmium and its effective removal from wastewater gains great attention. The main restriction for the Tl+ removal is the interference of a high concentration of co-existing ions in wastewater. Therefore, the goal of the current work was to synthesis adsorbent with high selectivity for the Tl+ removal. Herein, the pore size sieving strategy was proposed and Prussian blue-impregnated biochar (BC@PB) particles was synthesized. More than 95% Tl+ can be removed even the concentrations of the coexistence ions (Na+, Cd2+, and Zn2+) 1,000 higher than the initial concentration of Tl+ (500 μg/L). BC@PB also showed large adsorption capacity (9365 μg/g) and more than 99% Tl+ (initial concentration, 500 μg/L) were removed in just 1 min. The BC@PB had excellent and stable Tl+ removal ability (> 99%) over a range of pH from 3 to 9, which covered the pH range of common thallium-containing wastewater. The density functional theory (DFT) calculation confirmed that not only hydrated volume but also the hydration free energy of ions, which governed the energy barrier for ions entering into narrow channels of BC@PB, played essential roles on the selectivity removal of Tl+. Overall, due to its high selectivity, high adsorption capacity and easy preparation process, the synthesized BC@PB particles based on the pore sizing sieving strategy, can be a promising candidate for the removal of thallium from wastewater.

Ionic Covalent Organic Framework Membrane as Active Separator for Highly Reversible Zinc-Sulfur Battery.

Zinc-sulfur (Zn-S) batteries exhibit a high theoretical energy density, nontoxicity, and cost-effectiveness, demonstrating significant potential for integration into large-scale energy storage systems. However, the phenomenon of polysulfide (including dissolved S8 and Sx2-) shuttling is a major issue that results in rapid capacity decay and a short lifespan, limiting the practical performance of sulfur-based batteries. Herein, we fabricated an ionic covalent organic framework (iCOF) membrane as an active separator for the Zn-S battery. Sulfonic acid groups were introduced to the COF membrane, providing abundant negative charge sites in its pore wall. By combining size sieving and charge interaction between the polysulfide and pore wall, the iCOF membrane inhibited the crossover of polysulfides to the Zn metal anode without affecting the transport of metal ions. The Zn-S battery with the iCOF membrane as the separator shows a high-performance and low attenuation rate of 0.05% per cycle over 300 cycles at 2.5 A g-1. This study emphasizes the significance of separator design in enhancing Zn-S batteries and showcases the potential of functionalized framework materials for the development of high-performance energy storage systems.

Multifunctional membranes with super-wetting interface and in-situ Fenton-like sites for efficient oil-in-water emulsion separation

The surge in oil-in-water (O/W) emulsions poses a threat to the ecological environment. Membrane separation technology can achieve complete O/W emulsion separation through size sieving; however, its efficiency is limited by membrane fouling. In this study, an efficient O/W separation membrane with passive and positive anti-fouling properties was fabricated using Fe3O4 functionalized attapulgite (ATP) nanofibers. The anti-fouling mechanism of the multifunctional membranes for the separation of various O/W emulsions was studied. During separation process, a hydration layer, which mitigates oil adhesion with binding energy as low as −169 kcal·mol−1, forms on the interface of Fe3O4-ATP. When a cationic surfactant is present, positively charged oil droplets are attracted to the membrane surface, where they compress against each other, leading to demulsification and escape. Synergistic effects including electrostatic shielding, interaction energy, and steric hindrance were demonstrated through characterization and simulation. Our findings showed that the membrane exhibited a high filtration efficiency with an oil rejection of over 99 % and a steady flux of over 73 % of its initial value. After filtration, oil fouling degraded into smaller sizes and escaped from the membrane structure through the Fenton-like catalytic function of Fe3O4, resulting in a flux recovery ratio of up to 90 %. This study provides a reference for the construction of multifunctional membranes for efficient separation processes and advancing anti-fouling research on membrane interfaces.

Preparation of robust superhydrophobic stainless steel mesh for Oil-Water separation through Mn-Assisted control of one-step electrodeposited Zn growth

Removing oil spills from water presents a significant challenge in environmental remediation. Among various separation materials available, superhydrophobic materials have emerged as promising solutions, notable for their efficiency, cost-effectiveness, and eco-friendliness. The precise control of micro/nanostructure synthesis plays an essential role in creating superhydrophobic surfaces. Herein, the present study demonstrates controlled growth of well-defined hexagonal platelet-like micro/nanostructures of zinc crystals. This is achieved through deliberate manipulation of the electrodeposition crystal growth process, a facet frequently disregarded in previous studies. Notably, the present work, based on the distinctive properties of the Zn hexagonal close-packed structure (hcp), focuses on the effects of incorporating Mn and deposition parameters on the performance of Zn coatings. These findings offer valuable insights into selectively constructing Zn crystal planes for future electrodeposition endeavors. The resulting zinc/manganese stearate (SZM) coating on stainless steel mesh (SSM) shows remarkable water contact angles, reaching an impressive 163.1 ± 2.4°, in accordance with the Cassie-Baxter theory. This feature facilitates highly efficient oil–water separation. Coupled with size sieving of SSM, SZM coatings exhibit an oil–water separation efficiency of up to 99.86 % and a flux as high as 55.58 kL/m2h. Furthermore, the SZM coating exhibits long-lasting superhydrophobicity and exceptional corrosion resistance, even when subjected to challenging conditions such as high temperatures up to 200℃, pressure reaching 7 kg/cm2, or exposure to chemical and mechanical stresses. These enduring properties make SZM coatings suitable for constructing gravity-based and continuous oil–water separation systems, establishing them as a practical solution for diverse oil–water separation applications.

Size sieving and electrostatic exclusion synergetic strategy for high efficiency recovery of superbase-derived ionic liquids via nanofiltration from the spinning process

Superbase-derived ionic liquids (SILs) as the promising green solvents for cellulose spinning process should be urgently and deeply evaluated with respect to their recyclability. Herein, size sieving and electrostatic exclusion synergetic strategy was adopted for recycling four SILs ([DBUH][CH3CH2OCH2COO], [DBUH][CH3OCH2COO], [DBNH][CH3CH2OCH2COO], and [DBNH][CH3OCH2COO]) from aqueous solutions by the nanofiltration membranes (NF270 and NF90) at the first time. NF270 with larger pore and more negative charge was conducive to recycle SIL on account of a higher volume flux and the remarkably high IL rejection (＞95 %) compared to NF90. Rising the pressure and temperature played the positive role in the permeate flux of the membranes, whereas the elevated SIL concentration markedly decreased the electrostatic exclusion, leading to a decline in the recovery efficiency. Benefiting from the size sieving effect, the [DBNH][CH3OCH2COO] with small cation and anion structure could be recovered efficiently due to the high energy gap and big IL aggregates. Conversely, the strong electrostatic attraction was appeared between [DBUH][CH3CH2OCH2COO] (low energy gap and high positive charge density) and the membranes, leading to a decline in recovery efficiency. Furthermore, the combination of nanofiltration and evaporation to recover SIL from spinning wastewater effectively reduced the total recovery cost (1.51 $/Kg) in comparison with the evaporation only. Insight gained from this work suggested a high-efficiency and economical approach could be used in the recovery of SILs with small cations and anions size via large pore nanofiltration membranes during the industrialized cellulose spinning process.

Grain and flour physical and functional characteristics of Tef [Eragrostis tef (Zucc) Trotter] varieties of Ethiopia

Tef, a nutritious gluten-free cereal essential for making Ethiopia's traditional injera, varies in quality due to varieties and growing conditions. This study examined 35 tef varieties, revealing how variety, location, and season affect grain attributes and flour quality. Insights from growing tef in diverse Ethiopian agro-ecologies enhance understanding of its adaptability and quality. Physical and functional properties, including grain size, density, and flour absorption capacities, were analyzed, offering a comprehensive view of tef's potential in varying environments. Variety significantly affects tef characteristics, with genotype playing a major role in trait variation, influencing grain size, weight, and color. Sieve analysis showed that up to 45.78% of grain mass remained on larger sieves (425–600μm). Color metrics for tef varied, with white tef being lighter and redder than brown. Environmental factors like location and season influenced sieve separation outcomes and grain characteristics, except for the smallest sieve size and color parameters. The study also noted a relationship between grain size and color, with smaller, brown grains having lower lightness and yellowness. This study provides essential data: for future improvement and management of the tef; for quality assurance for consumers, processors, regulators and traders; and for designing of effective cleaning and processing techniques.

Insights into the pore size distribution of amorphous silica membranes using gas permeation activation energies

Silica-based membranes exhibit significant promise for the separation of hydrogen from other larger gas molecules based on size sieving mechanism, particularly when employed in membrane reactors. Nevertheless, the migration of silanol bonds (Si–OH) formed under hydrothermal conditions leads to alterations in pore size, ultimately compromising the performance of the membrane. Therefore, this study focuses on determining the pore size of cobalt-doped silica membranes before and after hydrothermal treatment by the apparent activation energy of gas permeation. The Oscillator model and the effective medium theory are employed to estimate the potential pore size distribution, as well as to calculate the apparent activation energy and permeability. The calculated apparent activation energy is compared with experimental data to identify the most probable pore size distribution, which showed the minimum activation energy error to the experimental value. The calculated permeability based on the identified pore size distribution is in line with experimental permeability, which validated the identified pore size distribution. Since silica-based membrane is generally applied in hydrothermal conditions, our model successfully identifies the changes in pore size of silica-based membranes after hydrothermal treatment. The results demonstrated that hydrothermal treatment significantly impacts the pore size of silica-based membranes. Specifically, 5-membered rings are prevalent in the intact membrane, but after hydrothermal treatment, there is a gradual shift of the pore size distribution towards larger pores, potentially leading to a decrease in sieving performance. This methodology presents a promising approach for determining intriguing pore size information of porous materials.

Microporous membrane with ionized sub-nanochannels enabling highly selective monovalent and divalent anion separation

Membranes tailored for selective ion transport represent a promising avenue toward enhancing sustainability across various fields including water treatment, resource recovery, and energy conversion and storage. While nanochannels formed by polymers of intrinsic microporosity (PIM) offer a compelling solution with their uniform and durable nanometer-sized pores, their effectiveness is hindered by limited interactions between ions and nanochannel. Herein, we introduce the randomly twisted V-shaped structure of Tröger’s Base unit and quaternary ammonium groups to construct ionized sub-nanochannel with a window size of 5.89–6.54 Å between anion hydration and Stokes diameter, which enhanced the dehydrated monovalent ion transport. Combining the size sieving and electrostatic interaction effects, sub-nanochannel membranes achieved exceptional ion selectivity of 106 for Cl-/CO32- and 82 for Cl-/SO42-, significantly surpassing the state-of-the-art membranes. This work provides an efficient template for creating functionalized sub-nanometer channels in PIM membranes, and paves the way for the development of precise ion separation applications.

Polyelectrolyte intercalated two-dimensional covalent organic framework membranes for efficient desalination

Two-dimensional covalent organic frameworks (2D COFs) have been proven to be ideal membrane materials for highly efficient separation. However, synergistic manipulation of the in-plane pores and interlayer channel structures of 2D COF membranes (COFMs) to acquire both high permeability and selectivity has rarely been reported. In this work, we synthesized TbTG COF nanosheets with intrinsic sub-nanometer pores, which were assembled with polyelectrolytes to form intercalated 2D COFMs. The sub-nanometer in-plane pores of the COF nanosheets endowed the COFM with size sieving capacity toward hydrated multivalent ions. The polyelectrolyte introduces numerous charged groups to the interlayer channels, enhancing the Donnan effect for desalination and also enlarging the interlayer distance to facilitate permeability. Accordingly, the in-plane pores and interlayer channels of the 2D COFM were synergistically engineered to simultaneously enhance the selectivity and permeability of COFMs. By adjusting the polyelectrolytes with different charged groups, the intercalated COFMs exhibited a high Na2SO4 rejection of 97.5 % and MgCl2 rejection of 99.4 %, respectively, as well as about a fourfold increase in permeability. Compared with the pure COFM. This work highlights the significance of interlayer channel structure of 2D COFMs for precise separations, providing new guidelines on the design and construction of advanced COFMs.

Faecal particle size distribution in relation to forage type and digestibility in horses: preliminary results

The study aimed to explore the connection between horses’ total tract apparent dry matter digestibility (ttaDMD) of various roughages and faecal particle size (FPS), to develop a tool to rank roughage digestibility. Six horses, varying in size and breed, were fed six distinct roughages (four cuts of fescue, perennial ryegrass/clover mix, and straw). Each feeding period lasted 16 days, with a 14-day adaptation phase. Faecal samples underwent wet sieving analysis. Roughage chemical composition was evaluated using NIRs. Faecal and roughage acid insoluble ash content were used to estimate ttaDMD and FPS was determined by wet sieving using a set of 6 sieves of different mesh sizes (S1 to S6; 6.50, 4.50, 2.36, 1.18, 0.6 and 0.15 mm respectively). The effects of roughage ttaDMD on FPS across sieves were analysed using GLM. Linear regressions and correlations were performed between faecal residues on each sieve and mesh sizes of the sieves to create a mathematical tool to rank ttaDMD based on FPS distribution. Increased ttaDMD was associated with larger FPS, with perennial ryegrass/clover mix (ttaDMD 74.44%) and straw (ttaDMD 44.57%) resulting in smaller and larger faecal particles respectively. Correlations were observed between ttaDMD, S1 and S2 (r = 0.639 and 0.668; p ≤ 0.001). The angular coefficient of the linear function between faecal residues on each sieve support the idea to estimate roughages digestibility from FPS (R2 = 0.4153). Consequently, determining faecal residues across sieves of varying mesh sizes could serve as an indirect method for ranking roughages digestibility.

Investigation on the mechanical properties of wood-plastic composites for the application of ceiling panels

Wood-plastic composites are relatively novel composite materials that consist of a blend of wood flour waste with high-density polyethylene and polypropylene plastic waste, designed for use in ceiling applications. Various samples were produced using different ratios from the total weight, including 20:80, 30:70, and 40:60, with sieve sizes of 0.425 mm, 1.18 mm, and 2 mm. The composites were created by melting plastics and sawdust at a temperature of 1800c utilizing the hot-press moldings technique employing diverse formulations. The properties of sample composites were analyzed experimentally based on ASTM standards to investigate water absorption levels as well as flexural strength, impact resistance hardness along with surface morphology via the design of experiments. This research study indicates that nine composite formulations consisting of HDPE and PP plastics combined with wood flour can produce favorable physio-mechanical properties. Among these various combination specimens tested in this study FS3/FC30N exhibited excellent physio-mechanical properties; including desirable values such as water absorption level at 5.5103%, flexural strength at 61.12 Mpa, impact resistance measuring 33.45 J cm−2, and hardness rating up to 80 RHB. Thus it is highly recommended for use in chipboard ceiling panel applications due to its potential benefits.

Sustainable Electrically Conductive Bio-Based Composites via Radical-Induced Cationic Frontal Photopolymerization.

Diglycidylether of vanillyl alcohol (DGEVA), in combination with mechanically recycled carbon fibers (RCFs), was used to make, via Radical-Induced Cationic Frontal Photopolymerization (RICFP), fully sustainable and bio-based conductive composites with good electrical conductivity and consequent Joule effect proprieties. Three different fiber lengths, using three different sieve sizes during the mechanical recycling process (0.2, 0.5, and 2.0 mm), were used in five different amounts (ranging from 1 to 25 phr). The samples were first characterized by dynamic mechanical thermal analysis (DMTA), followed byelectrical conductivity and Joule heating tests. More specifically, the mechanical properties of the composites increased when increasing fiber content. Furthermore, the composites obtained with the longest fibers showed the highest electrical conductivity, reaching a maximum of 11 S/m, due to their higher aspect ratio. In this context, the temperature reached by Joule effect was directly related to the electrical conductivity, and was able to reach an average and maximum temperatures of 80 °C and 120 °C, respectively, just by applying 6 V.

Preparation of polyethylene based composite nanofiltration membrane and its application in removal of heavy metals for water purification

The commercial polyethylene (PE) battery separator is well-suited as support for nanofiltration owing to its thickness of 7 um, high porosity, and strong mechanical properties. A new polyethylene based thin-film composite membrane was fabricated on the catechol/polyethyleneimine (CCh/PEI) modified PE support by pre-diffusion interfacial polymerization between piperazine (PIP) and trimesoyl chloride (TMC). By regulating the properties of the CCh/PEI layer and the PIP to influence the diffusion of PIP, a distinct worm-like structure in the polyamide (PA) layer was found, which provides more water penetration sites. After grafting melamine on the surface of PA layer, the TFC membrane exhibited outstanding chlorine resistance and the permeability of 12.5 L·m−2·h−1·bar−1 with the Mg2+ rejection of 94.5 %. Due to its small pore size, strong positively charged, and high adsorption capacity, the TFC membrane showed high rejection of heavy metal ions through pore size sieving, Donnan effect and adsorption. Therefore, it has great potential for water purification from heavy metal ions.