A Review on the Nanofiltration Process for Treating Wastewaters from the Petroleum Industry

Activities and/or processes in different segments of the petroleum industry, including upstream and downstream, generate aqueous waste streams containing oil and various contaminants that require treatment/purification before release/reuse. Nanofiltration (NF) technology has been approved as an efficient technology for treating wastewater streams from the petroleum industry. The primary critical issues in an NF treatment process can be listed as mitigation of membrane fouling; selection of appropriate pre-treatment process; and selection of a suitable, cost-effective, non-hazardous cleaning strategy. In this study, NF separation mechanisms, membrane fabrication/modification, effective factors on NF performance, and fouling are briefly reviewed. Then, a summary of recent NF treatment studies on various petroleum wastewaters and performance evaluation is presented. Finally, based on the gaps identified in the field, the conclusions and future perspectives are discussed

Nanocomposite membranes for water separation and purification: Fabrication, modification, and applications

Water pollution is one of the greatest challenges around the world. Nanocomposite membranes are a promising modified version of traditional polymeric membranes for water treatment, with three main characteristics of enhanced permeation, improved rejection and reduced fouling. For novel nanocomposite membranes, there is a strong connection between the membrane fabrication method, the properties of fabricated membranes, and membrane performance. This article, first, reviews the different nanocomposite membrane fabrication and modification techniques for mixed matrix membranes and thin film membranes for both pressure driven and non-pressure driven membranes using different types of nanoparticles, carbon-based materials, and polymers. In addition, the advanced techniques for surface locating nanomaterials on different types of membranes are discussed in detail. The effects of nanoparticle physicochemical properties, type, size, and concentration on membranes intrinsic properties such as pore morphology, porosity, pore size, hydrophilicity/hydrophobicity, membrane surface charge, and roughness are discussed and the performance of nanocomposite membranes in terms of flux permeation, contaminant rejection, and anti-fouling capability are compared. Secondly, the wide range of nanocomposite membrane applications, such as desalination and removal of various contaminants in water treatment processes, are discussed. Extensive background and examples are provided to help the reader understand the fundamental connections between the fabrication methods, membrane functionality, and membrane efficiency for different water treatment processes