Water Cleaning Adsorptive Membranes for Efficient Removal of Heavy Metals and Metalloids

Abstract

Heavy metal pollution represents an urgent worldwide problem due to the increasing number of its sources; it derives both from industrial, e.g., mining, metallurgical, incineration, etc., and agricultural sources, e.g., pesticide and fertilizer use. Features of membrane technology are the absence of phase change or chemical additives, modularity and easy scale-up, simplicity in concept and operation, energy efficiency, and small process footprint. Therefore, if membrane technology is coupled to adsorption technology, one of the most effective treatment strategies to remove heavy metals, namely, Adsorptive Membrane Technology, many typical disadvantages of traditional processes to remove heavy metals, such as low-quality treated water, excessive toxic sludge production, which requires further treatment, can be overcome. In this review, after a broad introduction on the relevance of heavy metal removal and the methods used, a thorough analysis of adsorptive membrane technology is given in terms of strategies to immobilize the adsorbents onto/into membranes and materials used. Regarding this latter aspect, the impressive number of papers present in the literature on the topic has been categorized into five types of adsorptive membranes, i.e., bio-based, bio-inspired, inorganic, functionalized, and MMMs.

An immobilized biosorbent from Paenibacillus dendritiformis dead cells and polyethersulfone for the sustainable bioremediation of lead from wastewater

“…Many of the common drawbacks of conventional processes to remove heavy metals, such as excessive toxic sludge production and low-quality treated water, can be overcome if membrane technology is combined with adsorption technology (Adsorptive Membrane Technology). This membrane offers a number of characteristics such as lack of phase change or chemical additives, flexibility and ease of scaling up, simplicity of idea and operation, energy efficiency, and small process footprint 8 . Adsorption is the most popular heavy metal removal technique due to its simplicity, versatility, low cost, and eco-friendliness.…”

Tailored Zeolitic Imidazolate Framework (TSC‐ZIF) for water purification: Evaluating TSC‐ZIF affinity towards heavy metal ions in multi‐metal solutions

“…All of these factors deem implementing efficient technologies to sequester heavy metals from water crucial. Different approaches were developed for reducing heavy metal contamination in water such as electro‐floatation, ion exchange, precipitation, oxidation–reduction, membrane separation, and adsorption 13–16 . Adsorption is among the most efficient methods in water treatment.…”

“…Different approaches were developed for reducing heavy metal contamination in water such as electro-floatation, ion exchange, precipitation, oxidation-reduction, membrane separation, and adsorption. [13][14][15][16] Adsorption is among the most efficient methods in water treatment. It is inexpensive, easy to operate, and regenerative in most cases.…”