Abstract
Aqueous sodium borohydride (NaBH4) is well known for its reducing property and well-established for the development of metal nanoparticles through reduction method. In contrary, this research paper discloses the importance of aqueous NaBH4 as a precipitating agent towards development of porous zirconium oxide. The boron species present in aqueous NaBH4 play an active role during gelation as well as phase separated out in the form of boron complex during precipitation, which helps to form boron free zirconium hydroxide [Zr(OH)4] in the as-synthesized condition. Evolved in-situ hydrogen (H2) gas-bubbles also play an important role to develop as-synthesized loose zirconium hydroxide and the presence of intra-particle voids in the loose zirconium hydroxide help to develop porous zirconium oxide during calcination process. Without any surface modification, this porous zirconium oxide quickly adsorbs almost hundred percentages of toxic lead ions from water solution within 15 minutes at normal pH condition. Adsorption kinetic models suggest that the adsorption process was surface reaction controlled chemisorption. Quick adsorption was governed by surface diffusion process and the adsorption kinetic was limited by pore diffusion. Five cycles of adsorption-desorption result suggests that the porous zirconium oxide can be reused efficiently for removal of Pb (II) ions from aqueous solution.
Highlights
Templates, because the highly energetic nuclei particles in solution coagulate with each other to form large agglomerate particles by decreasing their surface energy
It indicates that the as-prepared powders exhibit an average pore size of ~4 nm, which was well correlated with Transmission Electron Microscopy (TEM) result
The BJH curve indicates that the porous zirconium oxide exhibits wide pore size distribution in the range of 3.6 nm to 15.8 nm, with an average pore diameter of 4.6 nm, which was well correlated with TEM result
Summary
Templates, because the highly energetic nuclei particles in solution coagulate with each other to form large agglomerate particles by decreasing their surface energy In this context, a new progress has been made in tailoring the synthesis of agglomerated free or loose particles in the as-synthesized condition through gas-bubbles template mechanism. Gas-bubbles induced porous structure has been emerged as more advantageous than other pore forming methods because of simple room temperature synthesis, clean, template-free, environment friendly and short reaction time[18,23,24]. Gases such as N2, Ar, CO2, NH3 and H2S have been used as gas-bubbles template to induce the formation of various porous metal oxides materials[22,25,26]. We are emphasis on advantages of aqueous NaBH4 for the development of loose particles in the as-synthesized condition and development of thermally stable porous zirconium oxide nanomaterials for removal of toxic ions for environmental applications
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
