Smart in-line cleanup cartridge modules and floating sorbent systems for BrO3- removal from natural water sources – An innovative approach

Abstract

Functionalized montmorillonite–chitosan hybrid systems were developed as novel and cost-effective sorbent materials for the quantitative removal of carcinogenic bromate from natural water sources. The developed materials were custom fabricated via two facile and innovative approaches viz. reusable cartridge as a ‘point of use’ clean up modules and carbon cloth based “floating sorbents”, as a removal strategy at the ‘point of entry’. The packing density and flow rate of inline clean up cartridges as well as the sorbent coating and drying procedure of floating sorbent systems were sequentially optimized and validated. The application potential of the fabricated materials was subsequently explored and the studies revealed excellent removal efficiencies of > 99% for batch and flow based systems. The developed modules could successfully remove bromate levels in spiked natural water samples such as drinking, well and river water, down to 10 µgL−1 with more than 97% efficiency. The findings were substantiated through characterisation studies and detailed mechanistic investigation was carried out to understand the better adsorption characteristics of hybrid functionalized clay-chitosan composite. Consequently, the studies implied that a modular inline clean up cartridge packed with 600 g Mt-H-CTS sorbent connected to a water purification system is sufficient to quantitatively remove as high as 100 µgL−1 bromate for a middle class household on a monthly basis. Furthermore, the rapid and efficient regeneration of the material could improve the longevity and makes it an ideal candidate for post disinfection treatment applications at drinking water outlets such as taps (point of use) as well as for large reservoirs in the form of ‘floating sorbents.