An innovative platform exploiting solid microcrystalline cellulose for selective separation of bromate species in drinking water: Preparation, characterization, kinetics and thermodynamic study

Abstract

It is a major challenge to synthesis a cost-effective, efficient and reliable solid phase extractor with exceptional selectivity, capacity and reproducibility for removal of disinfection by-products (DBPs) in drinking water. Thus, the current study extends the analytical utility of microcrystalline cellulose (MCC) as a novel solid extractor against the underexplored bromate ions at trace levels as one of DBPs in drinking water. The proposed MCC platform was prepared via acid (HCl) hydrolysis of cellulose that was isolated from date pits (DPs). Fourier-transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopic (TEM) and thermal gravimetric analysis (TGA) were used for characterization of MCC sorbent prepared from DPs (D-MCC). Disappearance of the distinct FTIR peaks of hemicellulose and lignin were observed. The particle size of D-MCC ranged from 2.5 to 4 µm and rougher. SEM micrographs exhibited clear, smooth and stretched polymer structures on the surface and confirmed from the energy dispersive X-ray (EDX) spectra. SEM, TEM images and XRD data also revealed surface agglomeration in microstructures with a satisfactory crystallinity index of 80.81%. High stability of D-MCC was confirmed as compared to raw DPs A dual retention mechanism of bromate involving an ion association interaction of “weak base anion exchanger” and an added component of “surface adsorption” by the available surface area of the D-MCC is proposed. The D-MCC sorbent was successfully used for complete removal of BrO3− ions from environmental water samples. The sorbent presented extraordinary sorption capacity towards bromate ions in comparison to the frequently available extractor counterparts. D MCC can be packed in column for complete separation of trace levels of bromate ions from water from large volumes of water samples without decrease in its performance. Thus, this system can be utilized for ultra-trace determination of bromate in water using the standard addition method. The reusability of MCC towards bromate removal from drinking water is also included.