Recent Advances in Membranes Used for Nanofiltration to Remove Heavy Metals from Wastewater: A Review

Abstract

The presence of heavy metal ions in polluted wastewater represents a serious threat to human health, making proper disposal extremely important. The utilization of nanofiltration (NF) membranes has emerged as one of the most effective methods of heavy metal ion removal from wastewater due to their efficient operation, adaptable design, and affordability. NF membranes created from advanced materials are becoming increasingly popular due to their ability to depollute wastewater in a variety of circumstances. Tailoring the NF membrane’s properties to efficiently remove heavy metal ions from wastewater, interfacial polymerization, and grafting techniques, along with the addition of nano-fillers, have proven to be the most effective modification methods. This paper presents a review of the modification processes and NF membrane performances for the removal of heavy metals from wastewater, as well as the application of these membranes for heavy metal ion wastewater treatment. Very high treatment efficiencies, such as 99.90%, have been achieved using membranes composed of polyvinyl amine (PVAM) and glutaraldehyde (GA) for Cr3+ removal from wastewater. However, nanofiltration membranes have certain drawbacks, such as fouling of the NF membrane. Repeated cleaning of the membrane influences its lifetime.

Impact of Nitrate on the Removal of Pollutants from Water in Reducing Gas-Based Membrane Biofilm Reactors: A Review

“…NF membranes, positioned between UF and RO, are capable of removing organic substances, some inorganic ions, and microbes. RO membranes, with the smallest pore sizes, can nearly remove all dissolved solids, organic materials, and microbes, making them suitable for the preparation of high-purity water, such as in desalination processes [13][14][15]. Depending on the membrane material, hollow fiber membranes can be divided into organic and inorganic membranes, as shown in Table 1.…”

Positively Charged Polysulfone and Polyether Sulfone Mixed Matrix Membranes Modified with Polyethylenimine: Enhancing Heavy Metal Rejection and Antifouling Properties

“…Modifying the membrane surface to obtain a suitable charge can enhance the removal of heavy-metal ions from water. Modifying the surface charge of membranes is an effective way to enhance the heavy-metal removal efficiency. − Materials such as PEI, silica-poly­(ionic liquid) nanoparticles, layered clay materials, and adsorbed coatings can be used to modify the surface charge of membranes for heavy-metal removal. − A positively charged membrane, such as those modified with PEI, can effectively remove heavy-metal ions from water. A PEI/TMC membrane modified with an ionic liquid exhibited enhanced permeability and antibacterial properties for the removal of heavy metal ions.…”