L-arginine-enhanced PEI-based polyamide Nanofiltration membranes for efficient heavy metal ion removal

The pollution of toxic heavy metals is becoming an increasingly important issue in environmental remediation because these metals are harmful to the ecological environment and human health. Highly efficient selective removal of heavy metal ions is a huge challenge for wastewater purification. Here, highly efficient selective capacitive removal (SCR) of heavy metal ions from complex wastewater over Lewis base sites of S-doped Fe-N-C cathodes was originally performed via an electro-adsorption process. The SCR efficiency of heavy metal ions can reach 99% in a binary mixed solution [NaCl (100 ppm) and metal nitrate (10 ppm)]. Even the SCR efficiency of heavy metal ions in a mixed solution containing NaCl (100 ppm) and multicomponent metal nitrates (10 ppm for each) can approach 99%. Meanwhile, the electrode also demonstrated excellent cycle performance. It has been demonstrated that the doping of S can not only enhance the activity of Fe-N sites and improve the removal ability of heavy metal ions but also combine with heavy metal ions by forming covalent bonds of S- clusters on Lewis bases. This work demonstrates a prospective way for the selective removal of heavy metal ions in wastewater.

Fabrication of tight polyamide nanofiltration membrane by using a pyridine-diamine precursor for heavy metal ions removal

Heavy metal ions removal from metal plating wastewater using electrocoagulation: Kinetic study and process performance

UiO series of metal-organic frameworks composites as advanced sorbents for the removal of heavy metal ions: Synthesis, applications and adsorption mechanism

Considerable efforts are being made to develop new materials and technologies for the efficient and fast removal of toxic ions in drinking water. In this work, we developed a sulfur-complexed strategy to enhance the removal capability of heavy metal ions using the polyamide nanofiltration membrane by the covalent anchoring of l-cystine and l-cysteine. The sulfur-functionalized polyamide nanofiltration membrane exhibits superior complexation of heavy metal ions and can efficiently remove them from high-concentration wastewater. As a result, the sulfur-functionalized nanofiltration membrane not only showed excellent desalination performance but also achieved a record removal rate of heavy metal ions (99.99%), which can effectively reduce Hg(ii) concentration from 10 ppm to an extremely low level of 0.18 ppb, well below the acceptable limits in drinking water (2 ppb). Moreover, the sulfur-functionalized nanofiltration membrane showed an exciting long-term stability and can be easily regenerated without significant loss of Hg(ii) removal efficiency even after six cycles. Such outstanding performances were attributed to the synthetic effect of Hg–S coordinative interaction, electrostatic repulsion, and the sieving action of nanopores. These results highlight the tremendous potential of thiol/disulfide-functionalized NF active layer as an appealing platform for removing heavy metal ions from polluted water with high performance in environmental remediation.

Environmentally Benign TiO2 Nanomaterials for Removal of Heavy Metal Ions with Interfering Ions Present in Tap Water

The presence of heavy metals in the industrial effluents has recently been a challenging issue for human health. Efficient removal of heavy metal ions from environment is one of the most important issues from biological and environmental point of view, and many studies have been devoted to investigate the environmental behavior of nanoscale zerovalent iron (NZVI) for the removal of toxic heavy metal ions, present both in the surface and underground wastewater. The aim of this review is to show the excellent removal capacity and environmental remediation of NZVI-based materials for various heavy metal ions. A new look on NZVI-based materials (e.g., modified or matrix-supported NZVI materials) and possible interaction mechanism (e.g., adsorption, reduction and oxidation) and the latest environmental application. The effects of various environmental conditions (e.g., pH, temperature, coexisting oxy-anions and cations) and potential problems for the removal of heavy metal ions on NZVI-based materials with the DFT theoretical calculations and EXAFS technology are discussed. Research shows that NZVI-based materials have satisfactory removal capacities for heavy metal ions and play an important role in the environmental pollution cleanup. Possible improvement of NZVI-based materials and potential areas for future applications in environment remediation are also proposed.

Self-templated formation and characterization of polyhedral CoS hollow nanocage (HNC) for heavy metal ions (Ag+, Cd2+, Cu2+, Pb2+ and Zn2+) removal in aqueous solutions

Review: 157 refs.

Novel adsorptive PVC nanofibrous/thiol-functionalized TNT composite UF membranes for effective dynamic removal of heavy metal ions

A one‐pot biosynthesis of an aerogel composite based on attapulgite clay/bacterial cellulose to remove Pb²⁺ ion

The possibility of using the sorption technology to reduce the levels of metal ions present in urban storm-water runoff was investigated in this study. Seven sorbent materials including Amberlite XAD7, chitosan, crab shell, peat, Sargassum, sawdust, and sugarcane bagasse were initially examined for removal of 11 metal ions (Na, K, Ca, Mg, Mn, Co, Ni, Cu, Zn, Cd, and Pb) from simulated storm-water runoff at different concentrations. Among these sorbents, crab shell performed well with removal efficiencies exceeding 93% for all heavy metal ions examined and thus selected for further studies. Based on scanning electron microscopy/energy-dispersive x-ray analysis, microprecipitation of metal carbonates followed by adsorption onto the surface of crab shell was identified as the major mechanism responsible for removal of heavy metal ions by crab shell. Crab shell exhibited rapid removal of meal ions with attainment of biosorption equilibrium within 20 min. A crab-shell-packed column was used to study the continuous metal retention process. The column performed very well in the removal of heavy metal ions and was able to operate up to 192 h at a flow rate of 10 mL/min before outlet concentrations of Mn and Co reached 0.3 times of their respective inlet concentrations. Other metal ions such as Pb, Zn, Ni, Cd, and Cu were only in trace levels in the final effluent until 192 h. These findings would form the basis for the future development of crab-shell-based biofilters for removal of dissolved heavy metal ions from storm-water runoff.

Removal of heavy metal ions from dilute aqueous solutions by polymer–surfactant aggregates: A novel effluent treatment process

Heavy metal pollution is a severe problem worldwide. Great efforts have been devoted in developing effective and eco-friendly ways to remove heavy metal ions from contaminated water. However, challenges remain in terms of the high cost, the complex preparation processes required, low efficiency, and difficulties in scaling-up. Here, we report a sulfhydryl-functionalized wood (SH-wood) membrane featuring three-dimensional mesoporous and low-tortuosity lumens, which serve as multisite metal traps to achieve highly efficient heavy metal ion removal from wastewater. Benefiting from the unique microstructure of wood, the resulting membrane exhibits a high saturation uptake capacity of 169.5, 384.1, 593.9, and 710.0 mg·g-1 for Cu2+, Pb2+, Cd2+, and Hg2+ ions, respectively. Meanwhile, the SH-wood membrane can be easily regenerated at least eight times without apparent performance loss. Furthermore, stacking multilayers of the SH-wood filter is designed. Because of its high yet universal heavy metal ion absorbance capability, the multilayer SH-wood filter can effectively remove diverse heavy metal ions from real contaminated water, meeting the WHO standards while also displaying a high flux rate of 1.3 × 103 L·m-2·h-1. Our work presents a promising strategy for the scalable and highly efficient removal of heavy metal ions from sewage for environmental remediation.

Background: Nowadays, the challenge between clean water production and promoting an eco-friendly sorbent for the simultaneous fast and efficient removal of heavy metal ions is a hot topic and has attracted much attention. Objective: The objective of this study was to fabricate a novel material (PATP@PET) by incorporating poly-(2-amino thiophenol; PATP) into the matrix of Saudi Arabian petroleum coke (PET) for simultaneous fast and efficient removal of heavy metal ions. Method: The FTIR, EDX, SEM, and XRD techniques assessed the chemical structure and surface morphology of the thio-functionalized petcoke. The effects of medium pH, mass dosage of sorbent, metal ion concentration, and coexisting ions were investigated and optimized using batch sorption. Result: The excellent sorption capacity of PATP@PET sorbent towards the divalent lead and cadmium ions (98.44% and 312.5 mg.g-1 for Pb(II) and 90.15% and 217.4 mg.g-1 for Cd(II)) was realized by strong complex formation with the sulfur atoms of green petcoke and the thiol groups of poly-2- aminothiophenol moieties. The adsorption equilibrium data was best fitted to the pseudo-secondorder kinetic model and Langmuir adsorption isotherm. The reusability performance was tested for 10 cycles, and the simultaneous removal of Pb(II) and Cd(II) ions from industrial effluents was accomplished in 30 minutes with 100% removal efficiency at pH 6-7. Conclusion: PTAP-PET also demonstrated amazing performance for Cd(II) and Pb(II) removal in industrial wastewater samples. Subsequently, PTAP-PET contributes to developing fast, efficient, low-cost water remediation solutions for heavy metal ions that can potentially be translated into industrial- scale applications.