Synthesis of BaCO3 particles tailored by carboxylated cellulose fibers

The present work deals with the use of carboxylated cellulose fibers, thereafter called Cellulose Nano Fibers (CNF), as eco-friendly materials and sustainable resources for remediation and valuation, of metal ions present in contaminated water. Barium divalent cation (Ba 2+ ) is among the most common heavy metal pollutants found in water such as arsenic, cadmium, chromium, copper, nickel, lead and mercury. Thus, CNFs containing carboxylate groups were first prepared by the oxidation of the cellulose fibers using the NaOCl-NaBr-TEMPO system, and thereafter, they were used as adsorbent for Ba 2+ ions removal from BaCl 2 aqueous solutions. Such Ba 2+ removal was evidenced by the decrease of both the CNF surface charge and the CNF absorbance, upon the addition of the metal divalent cation, BaCl 2 to the CNF aqueous dispersions. It is shown that the interaction occurring between the fiber carboxylic groups and the positively charged metal ions, Ba 2+ , occurs via electrostatic interactions and leads to the CNFs –Ba 2+ complex formation. In the second part of this work, we investigated the effect of the CNFs on the crystallogenesis of barium carbonate particles, BaCO 3 . Thus, the CNFs aqueous solution was first added to barium chloride BaCl 2 solution, and the mixture was stirred for a period of time (complexation time), prior the addition of sodium carbonate (Na 2 CO 3 ) solution. The precipitation of barium carbonate particles in the presence of CNFs occurred at ambient temperature, in a water-jacketed Pyrex glass vessel. Finally, the resulting Barium carbonate-CNFs composites were examined by various methods such as Scanning Electronic Microscopy (SEM), and X-ray Diffraction. From the SEM data, two BaCO 3 morphologies were observed, dendritic and bent or rods particles, respectively, in the absence and in the presence of the CNFs.