Waste Reutilization in Polymeric Membrane Fabrication: A New Direction in Membranes for Separation

Abstract

In parallel to the rapid growth in economic and social activities, there has been an undesirable increase in environmental degradation due to the massively produced and disposed waste. The need to manage waste in a more innovative manner has become an urgent matter. In response to the call for circular economy, some solid wastes can offer plenty of opportunities to be reutilized as raw materials for the fabrication of functional, high-value products. In the context of solid waste-derived polymeric membrane development, this strategy can pave a way to reduce the consumption of conventional feedstock for the production of synthetic polymers and simultaneously to dampen the negative environmental impacts resulting from the improper management of these solid wastes. The review aims to offer a platform for overviewing the potentials of reutilizing solid waste in liquid separation membrane fabrication by covering the important aspects, including waste pretreatment and raw material extraction, membrane fabrication and characterizations, as well as the separation performance evaluation of the resultant membranes. Three major types of waste-derived polymeric raw materials, namely keratin, cellulose, and plastics, are discussed based on the waste origins, limitations in the waste processing, and their conversion into polymeric membranes. With the promising material properties and viability of processing facilities, recycling and reutilization of waste resources for membrane fabrication are deemed to be a promising strategy that can bring about huge benefits in multiple ways, especially to make a step closer to sustainable and green membrane production.

Green and Non‐Conventional Materials for Membrane Synthesis: A Review

“…Most of the bio‐polymers discussed above can be extracted from waste materials taking us a step closer to sustainability. Cellulose Acetate can be obtained from regenerated cellulose like newspapers [7] and waste cigarette filters which happen to be the most abundant forms of waste present globally [4] . It is estimated that 30 billion tons of waste, rich in keratin associated with feathers and wool are produced every year [4] .…”

“…[4] It is estimated that 30 billion tons of waste, rich in keratin associated with feathers and wool are produced every year. [4] Proper usage of these wastes will not only help us to solve environmental issues but also can be produced in large quantities. This finds applications in not only membrane separation but also in water remediation, cosmetics and food packing.…”

“…These are carcinogenic and cause skin irritation, mutations in germ cells, infertility, eye, and respiratory infections. A whopping 95 % of the total waste generated during the industrial membrane fabrication process is due to the contamination of wastewater by these solvents [3,4] …”

“…reported the process to be unstable, and the membrane yielded poor performance. Adoption of green eco‐friendly solvents is not enough, factors like membrane performance and cost play a huge role [4] …”

“…Hairy parts of animals and wool from the textile fabric are an important source of keratin extraction as they contain keratin up to 95 %. [4] One of the simplest and most recent methods of keratin preparation is based on human hair. The hair is initially cleaned using soap or alcohol followed by the process of delipidation which involves treating it with chloroform and methanol for 24 hours.…”