Mussels inspire super-efficient wastewater treatment

Image: Matt Seymour

An eco-friendly material, which can remove dyes from industrial wastewater, has been developed using materials inspired by mussels.

The material, which is made from a polymer called polydopamine, modified with an 'ionic liquid' - which is a salt in liquid state - has been developed by researchers from Khalifa University, Abu Dhabi, UAE. This new adsorbent material for the removal of chemical pollutants from water is highly selective and efficient, making it a game-changer for water treatment.

Dyes are used in many industrial applications, but the effluents of some industries, including textile production, contain toxic chemicals, which are detrimental to both the environment and human health. This means wastewater containing dyes must be properly treated before being discharged to rivers and other water bodies.

“Surface and groundwater pollution caused by industrial dye-loaded wastewater effluents threatens human health and ecological systems, causing a serious environmental problem in many countries.”

Professor Hassan Arafat, Khalifa University

The team behind this discovery are Hassan Arafat, professor of chemical engineering and director of the research and innovation center in graphene and 2D Materials, Rawan Abu Alwan, Research Associate, Botagoz Zhuman, Research Assistant, Dr. Mahendra Kumar, Research Scientist, and Prof. Enas Nashef, Professor of Chemical Engineering.

Hassan Arafat, professor of chemical engineering, and director of the research & innovation center for graphene and 2D materials, explains that anionic pollutants carry a negative charge and are often found in industrial wastewaters from a variety of sources, including metal plating, mining and textile dyeing.

“Surface and groundwater pollution caused by industrial dye-loaded wastewater effluents threaten human health and ecological systems, causing a serious environmental problem in many countries,” he said.

“Several treatment techniques have been applied to remove dyes from wastewater, and among these, adsorption is considered the most economically feasible and easily applied. However, traditional adsorbents offer low selectivity and the process can produce secondary waste products.”

For better dye removal from wastewater, a highly selective adsorbent is needed. Recent research attention has turned to nanomaterials as these have high removal capacities and high selectivity. However, nanomaterials also bring major limitations: They are expensive, not always reusable and can be toxic themselves.

Instead, the research team turned to nature for inspiration.

Image: Manu Mateo

Mussels are marine animals that attach themselves to a variety of surfaces using byssus threads, which are made from a protein containing dopamine. In humans and mammals, dopamine is a neurotransmitter that plays a role in reward-motivated behavior, but in mussels, it acts as a natural adhesive.

Polydopamine is a synthetic polymer that mimics the structure of this dopamine-containing protein. It has the ability to coat a variety of surfaces and provides a versatile platform for surface modifications.

“As a material with many functional groups, extraordinary self-adhesive properties, and biocompatibility, the potential applications for polydopamine-based materials are abundant,” Professor Arafat explained.

The work has been published in Chemical Engineering Journal.