Project Lead(s): Michael Tam
While the textile industry is a major employer in many developing countries, due to its use of unskilled labour, textile companies produce large amounts of liquid waste that contain organic and inorganic compounds.
Each year, approximately 800,000 tons of synthetic dyes are prepared for use in a number of industries, including textiles, and it has been estimated that up to 15% of these dyes end up in wastewater streams, where they persist due to their stability in solution and resistance to natural bio degradative processes.
This has raised a number of environmental concerns and, in many cases, water polluted with these dyes becomes unsafe for human consumption.
The object of this project was to use sustainable nanomaterials (cellulose nanocrystals or cellulose nanofibrils) to absorb organic dyes from textile mill effluents.
Surface functionalization of cellulose nanocrystals (CNCs) was conducted to capture specific pollutants. Unlike conventional adsorbents (e.g., activated carbon), the CNCs incorporated hydrogels that were tailored to capture pollutants via electrostatic attraction between counter-ions.
These nanomaterials were integrated into a potable pilot water treatment system that was transported to the test site, a Batik factory in Indonesia.
The aim was to demonstrate that they could remove the organic dyes from the wastewater before discharging it to the river.
The team successfully produced high-performance absorbents from cellulose nanocrystals (CNCs) derived from natural resources, such as plants.
They were able to selectively modify the CNC to target specific dye molecules; their effectiveness was confirmed and demonstrated.
The adsorption characteristics of CNC–ALG hydrogel beads were evaluated using batch adsorption studies of methylene blue (MB) in aqueous solution.
Thermodynamic analyses confirmed that the adsorption process is spontaneous and exothermic.
The team demonstrated that, after five adsorption–desorption cycles, the removal efficiency of MB remained at about 97%, and the CNC–ALG hydrogel beads were effective adsorbents for the removal of organic dyes from wastewaters.
The team has filed a patent disclosure to protect the invention and knowledge of the project has been disseminated through publications.
Work is underway with organizations in Southeast Asia, including the Nanyang Environmental and Water Research Institute (NEWRI), to explore partnership and modes of taking the technology to other countries.
Once the field trial results are completed, the team will evaluate the feasibility of moving the project to the next stage.