Textile Wastewater Treatment By Magnetic Nanoadsorbents

The project: Nanotechnology for textile wastewater treatment

Textile industries, which are major consumers of fresh water, release significant amount of colors or organic dyestuffs in their effluents. The presence of dyes in wastewater poses an environmental concern since these organic dyes are toxic to aquatic and non-aquatic life. Their toxicity is well documented. Therefore, removing dyes from wastewater is essential before discharging effluents into the environment. However, these dyes are difficult to remove, non-biodegradable and exist for a long time in the environment, which makes it challenging to the conventional wastewater treatment techniques.

A number of chemical, physical and biological conventional treatment methods have been developed for decolourization of textile wastewater (dye effluents); including coagulation–flocculation, precipitation, oxidation, ion exchange and membrane filtration, adsorption onto activated carbon and low cost adsorbents, etc. These methods are found to be limited because of their high cost, ineffectiveness in meeting stringent effluent standards, and the huge amount of sludge they could generate. 

Currently, the application of nanotechnology (i.e., the technology related to the utilization of materials at nanoscale, 1-100 nm) has emerged as a fascinating area of interest for removal of various contaminants from wastewater effluents. Nanoparticles (NPs) are the drivers of the nanotechnology revolution. They display unexpected properties that differ from their bulk material counterparts. NPs pose high adsorption capacities and affinities because of their specific functionality and large specific surface areas, i.e., surface area per unit mass. Due to these unique properties, nanoparticles have potential applications for the treatment of textile wastewater. Another important advantage of using magnetic NPs for the removal of environmental pollutants lies on the fact that they cost-effectively meet the environmental regulation for wastewater treatment, as they can be prepared in situ where treatment is needed and recovered by simple magnet; translating into reduced operating and processing costs.

In this project we aim at investigating the effectiveness of the magnetic iron oxide NPs in the removal of large organic contaminants (dyes) from real textile wastewater. This study provides valuable insight on the effect of NPs toward the treatment and recyclability of textile wastewater, which is crucial for the textile industry. In this study, a batch-contact-time method is used for the treatment of a real textile wastewater sample obtained from a local factory in the city of Nablus. The effects of different experimental parameters such as contact time, initial concentration, NPs dose, solution pH, and coexisting anions on dye removal are investigated. Results showed that dye adsorption was fast, and equilibrium was achieved within 10 min.  The adsorption equilibrium data fit very well to Langmuir and Freundlich adsorption isotherm models. The thermodynamics studies indicated that the adsorption was spontaneous, endothermic and physical in nature. The desorption and regeneration studies have proven that NPs can be employed repeatedly without impacting its adsorption capacity. Therefore, magnetic NPs are recommended as fast, effective and inexpensive adsorbents for rapid removal and recovery of contaminants from wastewater effluents, like textile industry.